TW202436997A - Mask blank, transfer mask, method for manufacturing transfer mask, and method for manufacturing display device - Google Patents

Abstract

Provided is a mask blank which satisfies the requirement of high light fastness with respect to an exposure light including a wavelength of an ultraviolet ray region. A mask blank including a thin film for pattern formation on a transparent substrate, the thin film contains a transition metal and silicon, and in which an X-ray absorbing spectrum of the thin film acquired by an X‐ray absorption spectroscopy method has a pre-edge in an incident energy of X-ray within the range of 400eV or more and 402eV or less.

Description

Photomask base, transfer photomask, method for manufacturing transfer photomask, and method for manufacturing display device

The present invention relates to a mask base, a transfer mask, a method for manufacturing the transfer mask, and a method for manufacturing a display device.

In recent years, in display devices such as FPD (Flat Panel Display) represented by OLED (Organic Light Emitting Diode), with the development of large screen, wide viewing angle, foldable and other flexibility, high-definition and high-speed display are also developing rapidly. One of the elements required to achieve such high-definition and high-speed display is to produce electronic circuit patterns of components and wiring with fine and high dimensional accuracy. In the patterning of electronic circuits for such display devices, photolithography is mostly used. Therefore, a transfer mask (photomask) such as a phase shift mask and a binary mask for manufacturing display devices that form fine and high-precision patterns is required.

For example, Patent Document 1 describes a photomask for exposing fine patterns. Patent Document 1 describes that the photomask pattern formed on the transparent substrate of the photomask is composed of a transparent portion and a semi-transparent portion, the transparent portion allows light of an intensity that is substantially helpful for exposure to pass through, and the semi-transparent portion allows light of an intensity that is substantially unhelpful for exposure to pass through. Furthermore, Patent Document 1 describes that by utilizing a phase shift effect, light passing through the semi-transparent portion and the transparent portion near the boundary cancels each other out to increase the contrast of the boundary. Furthermore, Patent Document 1 describes that the semi-transparent portion of the photomask is composed of a thin film containing the following substance, the substance having nitrogen, metal, and silicon as main components, and the photomask contains 34 to 60 atomic % of silicon as a component of the substance constituting the thin film.

Patent document 2 describes a half-tone phase-shifted mask-substrate for lithography. Patent document 2 describes that the mask-substrate has a substrate, an etch-stop layer deposited on the substrate, and a phase-shifted layer deposited on the etch-stop layer. Furthermore, Patent document 2 describes that using the mask-substrate, a mask having a phase shift of approximately 180 degrees and a transmittance of at least 0.001% at a selected wavelength less than 500 nm can be manufactured. [Prior art document] [Patent document]

[Patent document 1] Japanese Patent Publication No. 2966369 [Patent document 2] Japanese Patent List No. 2005-522740

[The problem the invention is trying to solve]

As a transfer mask used in the production of high-definition (1000 ppi or more) panels in recent years, in order to achieve high-resolution pattern transfer, a transfer mask is required, which forms a transfer pattern, and the transfer pattern includes a thin film pattern for forming a fine pattern with a hole diameter of less than 6 μm and a line width of less than 4 μm. Specifically, a transfer mask is required, which forms a transfer pattern including a fine pattern with a diameter or width size of 1.5 μm.

On the other hand, the transfer mask obtained by patterning the pattern forming film of the mask base is repeatedly used to transfer the pattern to the transfer object, so it is expected that the light resistance to ultraviolet rays (ultraviolet light resistance) during actual pattern transfer is also high.

However, it has been difficult to manufacture a photomask blank having a pattern-forming film that satisfies the requirement for ultraviolet light resistance (hereinafter referred to as light resistance) to exposure light having a wavelength including the ultraviolet region.

The present invention is made to solve the above-mentioned problems. That is, the purpose of the present invention is to provide a photomask substrate that meets the requirement of having higher light resistance to exposure light with a wavelength including the ultraviolet region.

Furthermore, the purpose of the present invention is to provide a transfer mask having a good transfer pattern, a method for manufacturing the transfer mask, and a method for manufacturing a display device, wherein the good transfer pattern satisfies the requirement of having high light resistance to exposure light having a wavelength including the ultraviolet region. [Technical means for solving the problem]

The present invention has the following structure as a technical means to solve the above-mentioned problems.

(Composition 1) A photomask base characterized in that: it is a thin film for pattern formation on a light-transmitting substrate, and the thin film contains transition metal and silicon, and the X-ray absorption spectrum of the thin film obtained by X-ray absorption spectroscopy has a pre-edge in the range of incident X-ray energy of 400 eV to 402 eV.

(Configuration 2) A mask substrate as described in Configuration 1, wherein the X-ray absorption spectrum of the thin film has an absorption edge within the range of incident X-ray energy of 403 eV to 406 eV.

(Configuration 3) The mask substrate as described in Configuration 2, wherein when the maximum value of the X-ray absorption coefficient at the front of the edge is set to IP and the maximum value of the X-ray absorption coefficient at the absorption end is set to IA, IA/IP satisfies a relationship of less than 1.45.

(Configuration 4) A mask substrate as described in Configuration 1, wherein the thin film further contains nitrogen.

(Configuration 5) A mask substrate as described in Configuration 1, wherein the thin film contains at least titanium as the transition metal.

(Configuration 6) The mask substrate as described in Configuration 1, wherein the ratio of the content of the transition metal in the above-mentioned thin film to the total content of the transition metal and silicon is greater than 0.05.

(Configuration 7) The mask base as described in Configuration 1 has an etching mask film on the thin film having an etching selectivity different from that of the thin film.

(Configuration 8) A mask substrate as described in Configuration 7, wherein the etching mask film contains chromium.

(Construction 9) A transfer mask, characterized in that: it is a thin film with a transfer pattern formed on a light-transmitting substrate, and the thin film contains transition metal and silicon, and the X-ray absorption spectrum of the thin film obtained by X-ray absorption spectroscopy has an edge in the range of incident X-ray energy of 400 eV to 402 eV.

(Configuration 10) A transfer mask as described in Configuration 9, wherein the X-ray absorption spectrum of the thin film has an absorption edge in the range of incident X-ray energy of not less than 403 eV and not more than 406 eV.

(Configuration 11) In the transfer mask as described in Configuration 10, when the maximum value of the X-ray absorption coefficient at the front of the edge is set to IP and the maximum value of the X-ray absorption coefficient at the absorption end is set to IA, IA/IP satisfies a relationship of less than 1.45.

(Configuration 12) A transfer mask as described in Configuration 9, wherein the thin film further contains nitrogen.

(Configuration 13) A transfer mask as described in Configuration 9, wherein the thin film contains at least titanium as the transition metal.

(Configuration 14) The transfer mask as described in Configuration 9, wherein the ratio of the content of the transition metal in the above-mentioned thin film to the total content of the transition metal and silicon is greater than 0.05.

(Constitution 15) A method for manufacturing a transfer mask, characterized in that it includes the following steps: Preparing a mask base as described in constitution 7 or 8; Forming an anti-etching film having a transfer pattern on the etching mask film; Performing wet etching using the anti-etching film as a mask to form a transfer pattern on the etching mask film; and Performing wet etching using the etching mask film having the transfer pattern as a mask to form a transfer pattern on the thin film.

(Construction 16) A method for manufacturing a display device, characterized by comprising the following steps: Placing a transfer mask as described in any one of Constructions 9 to 14 on a mask stage of an exposure device; and Irradiating the transfer mask with exposure light to transfer a transfer pattern to an anti-corrosion film provided on a substrate for a display device. [Effect of the invention]

According to the present invention, a photomask blank can be provided, which satisfies the requirement of having higher light resistance to exposure light having a wavelength including the ultraviolet region.

Furthermore, according to the present invention, a transfer mask having a good transfer pattern, a method for manufacturing the transfer mask, and a method for manufacturing a display device can be provided. The above-mentioned good transfer pattern meets the requirement of having higher light resistance to exposure light with a wavelength including the ultraviolet region.

First, the reasons for completing the present invention are explained. The inventors of the present invention have made great efforts to study the composition of the following photomask substrate, which satisfies the requirement of having high light resistance to exposure light of wavelengths including the ultraviolet region (hereinafter, sometimes referred to as "exposure light"). The inventors of the present invention have conducted the following research, namely, using a transition metal silicide-based material containing a transition metal and silicon as a material for a thin film pattern of a transfer mask for manufacturing a display device such as an FPD (Flat Panel Display). It has been found that in thin films formed using transition metal silicide-based materials, although the composition is roughly the same, there may be large differences in light resistance to exposure light. Therefore, the inventors have verified the difference between thin films of transition metal silicide materials with higher light resistance to exposure light and thin films of transition metal silicide materials with lower light resistance to exposure light in many aspects. First, the inventors studied the correlation between the composition of the film and the light resistance to exposure light, but no clear correlation was obtained between the composition of the film and the light resistance. In addition, cross-sectional SEM (scanning electron microscope) images, top-view STEM (scanning transmission electron microscopy) images, or electron diffraction images were observed, but no clear relationship was obtained between them and the light resistance.

Therefore, the inventors of the present invention focused on the gas components used when forming a thin film. When a thin film of a transition metal silicide material is formed on a light-transmitting substrate, a sputtering method is generally used. When a thin film of a transition metal silicide material is formed by sputtering, a reactive gas and a rare gas are generally flowed into the film forming chamber. The inventors of the present invention have further conducted diligent research and have found that, for transition metal silicide material films having greatly different light resistance to exposure light having a wavelength including the ultraviolet region, X-ray absorption spectra were obtained by X-ray absorption spectroscopy (horizontal axis: X-ray energy incident on the film (incident X-ray energy), vertical axis: X-ray absorption coefficient of the film relative to the X-ray energy). As a result, in the X-ray absorption spectrum within the range of incident X-ray energy originating from nitrogen in the reactive gas, there is a clear difference in the tendency of the X-ray absorption coefficient between the two. More specifically, it was found that in a transition metal silicide material film having good light resistance to exposure light of a wavelength including the ultraviolet region, a pre-edge of a peak with a relatively small X-ray absorption coefficient appears in the incident X-ray absorption energy (range of 400 eV to 402 eV) before the absorption edge of a peak with a large X-ray absorption coefficient appears (range of 403 eV to 406 eV).

The photomask base of the present invention is derived from the results of the above efforts. That is, the characteristics of the photomask base of the present invention are: a thin film for pattern formation is provided on a transparent substrate, and the thin film contains transition metal and silicon, and the X-ray absorption spectrum of the above thin film obtained by X-ray absorption spectroscopy has an edge in the range of X-ray incident energy of 400 eV to 402 eV. Below, the implementation method of the present invention is specifically described with reference to the drawings. Furthermore, the following implementation method is a form of the present invention when it is concretized, and does not limit the present invention to its scope.

Fig. 1 is a schematic diagram showing the film structure of a photomask base 10 of the present embodiment. The photomask base 10 shown in Fig. 1 comprises: a light-transmitting substrate 20, a pattern-forming thin film 30 (e.g., a phase shift film) formed on the light-transmitting substrate 20, and an etching mask film (e.g., a light-shielding film) 40 formed on the pattern-forming thin film 30.

Fig. 2 is a schematic diagram showing a film structure of a photomask blank 10 according to another embodiment. The photomask blank 10 shown in Fig. 2 includes a light-transmitting substrate 20 and a pattern-forming thin film 30 (eg, a phase shift film) formed on the light-transmitting substrate 20.

In this specification, "the film 30 for pattern formation" means a film such as a light shielding film and a phase shifting film for forming a specific fine pattern in the transfer mask 100 (hereinafter, sometimes referred to as "the film 30"). Furthermore, in the description of this embodiment, a phase shifting film is sometimes cited as a specific example of the film 30 for pattern formation, and a phase shifting film pattern is sometimes cited as a specific example of the film pattern 30a for pattern formation (hereinafter, sometimes referred to as "the film pattern 30a"). Other film 30 for pattern formation and film pattern 30a for pattern formation, such as a light shielding film and a light shielding film pattern, a transmittance adjusting film and a transmittance adjusting film pattern, are also the same as the phase shifting film and the phase shifting film pattern.

Hereinafter, the light-transmitting substrate 20, the pattern-forming thin film 30 (eg, a phase shift film), and the etching mask film 40 constituting the mask base 10 for manufacturing a display device according to the present embodiment will be described in detail.

<Transparent substrate 20> The transparent substrate 20 is transparent to the exposure light. When the surface reflection loss of the transparent substrate 20 is set to zero, the transmittance of the exposure light is 85% or more, preferably 90% or more. The transparent substrate 20 includes a material containing silicon and oxygen, and can be composed of glass materials such as synthetic quartz glass, quartz glass, aluminum silicate glass, sodium calcium glass, and low thermal expansion glass ( _SiO2 - _TiO2 glass, etc.). When the transparent substrate 20 includes low thermal expansion glass, the position change of the thin film pattern 30a caused by the thermal deformation of the transparent substrate 20 can be suppressed. In addition, the transparent substrate 20 used in the display device application is generally a rectangular substrate. Specifically, a light-transmitting substrate 20 having a main surface (a surface for forming a pattern-forming film 30) with a short side length of 300 mm or more can be used. In the photomask base 10 of the present embodiment, a larger-sized light-transmitting substrate 20 having a short side length of 300 mm or more can be used. The photomask base 10 of the present embodiment can be used to manufacture a transfer mask 100 having a transfer pattern on a light-transmitting substrate 20, for example, including a fine pattern-forming film pattern 30a having a width dimension and/or a diameter dimension of less than 2.0 μm. By using such a transfer mask 100 of the present embodiment, a transfer pattern including a specific fine pattern can be stably transferred to a transferee.

<Thin film 30 for pattern formation> The X-ray absorption spectrum of the thin film 30 obtained by the X-ray absorption spectroscopy method of the display device manufacturing photomask base 10 of the present embodiment (hereinafter, sometimes referred to as "the photomask base 10 of the present embodiment") has an edge in the range of the incident energy of the X-rays being 400 eV or more and 402 eV or less. The X-ray absorption spectrum can be obtained by irradiating a sample (thin film) with X-rays, measuring the secondary electrons released from the sample and indirectly deriving the X-ray absorption coefficient, the so-called electron yield method. In addition, the fluorescence yield method can also be used to obtain the X-ray absorption spectrum.

The inventors of the present invention speculated the relationship between the tendency of the X-ray absorption coefficient and the light resistance as follows. When a pattern-forming thin film 30 containing transition metal and silicon is formed on a light-transmitting substrate 20 by sputtering using a sputtering gas containing nitrogen in a film-forming chamber, it is believed that nitrogen is introduced into the thin film 30 in a state of bonding with the transition metal or silicon. The inventors of the present invention have found that when an X-ray absorption spectrum within a range of incident X-ray energy originating from nitrogen is obtained by X-ray absorption spectroscopy, as shown in FIGS. 5 and 6 , in a pattern-forming thin film 30 having good light resistance to exposure light, a pre-edge of a peak having a relatively small X-ray absorption coefficient appears in an incident X-ray absorption energy (range of 400 eV to 402 eV) near an absorption edge (Absorption edge) of a peak having a large X-ray absorption coefficient (range of 403 eV to 406 eV). On the other hand, it was found that in the film 30 with poor light resistance to exposure light, the pre-edge of the peak with a relatively small X-ray absorption coefficient did not appear in the incident X-ray absorption energy (range of 400 eV to 402 eV) before the absorption edge of the peak with a large X-ray absorption coefficient (range of 403 eV to 406 eV).

In the film with a distinct nitrogen pre-edge peak, it is believed that there is a large amount of nitrogen in a state of being firmly bonded to other elements (mainly transition metals or silicon). In order to change the bonding state (strip off electrons), more energy is required. Therefore, more energy is required to deteriorate the film quality (mainly the increase in transmittance caused by the release of the bond between the transition metal or silicon and nitrogen and the bond with oxygen) due to irradiation with ultraviolet energy of several eV. As a result, it is speculated that the film with a distinct pre-edge peak is a film with higher light resistance to exposure light with a wavelength including the ultraviolet region. However, this speculation is based on the current view and does not limit the scope of the invention.

The X-ray absorption spectrum of the pattern-forming thin film 30 (hereinafter, sometimes referred to as "thin film 30") preferably has an absorption edge in the range of incident X-ray energy of 403 eV to 406 eV. The reason is that the thin film having an absorption edge in the incident X-ray energy range contains nitrogen at a certain ratio or more. Regarding the X-ray absorption spectrum of the pattern-forming thin film 30, from the viewpoint of obtaining higher light resistance to exposure light of a wavelength including the ultraviolet region, it is preferred that when the maximum value of the X-ray absorption coefficient at the absorption edge of the X-ray absorption spectrum of the thin film 30 is set to IA and the maximum value of the X-ray absorption spectrum at the edge is set to IP, IA/IP satisfies a relationship of 1.45 or less, and more preferably satisfies a relationship of 1.40 or less. On the other hand, IA/IP is preferably above 1.0, and more preferably above 1.05.

Furthermore, the X-ray absorption coefficient IA at the absorption end is preferably the maximum value of the X-ray absorption coefficient within the range of incident X-ray energy of 403 eV to 406 eV, and more preferably the maximum value of the X-ray absorption coefficient within the range of incident X-ray energy of 404 eV to 405 eV. Furthermore, the X-ray absorption coefficient IP at the edge is preferably the maximum value of the X-ray absorption coefficient within the range of incident X-ray energy of 400 eV to 401 eV.

Regarding the X-ray absorption spectrum of the pattern forming film 30, from the viewpoint of obtaining higher light resistance to exposure light of a wavelength including the ultraviolet region, it is preferred that when the maximum value of the X-ray absorption coefficient at the edge front is set as IP and the minimum value of the X-ray absorption coefficient in the valley of the X-ray absorption spectrum between the edge front and the absorption end is set as IV, IP/IV satisfies a relationship of 1.0 or more. The X-ray absorption coefficient IV in the valley of the X-ray absorption spectrum between the edge front and the absorption end is preferably the minimum value of the X-ray absorption coefficient in the range of incident X-ray energy greater than 401 eV and less than 402 eV.

The pattern forming film 30 may include a material containing a transition metal and silicon (Si). As the transition metal, molybdenum (Mo), tungsten (W), titanium (Ti), zirconium (Zr), etc. are preferred, and titanium and molybdenum are more preferred. In addition, the pattern forming film 30 preferably contains at least titanium as a transition metal. The pattern forming film 30 may be a phase shift film having a phase shift function.

The ratio of the content of the transition metal in the pattern-forming thin film 30 to the total content of the transition metal and silicon is preferably 0.05 or more, more preferably 0.10 or more. By satisfying these ratios, both the optical characteristics and chemical resistance can be improved. In addition, the ratio of the content of the transition metal in the pattern-forming thin film 30 to the total content of the transition metal and silicon is preferably 0.50 or less, more preferably 0.40 or less. By satisfying these ratios, the excessive increase in the wet etching rate during pattern formation of the pattern-forming thin film 30 can be suppressed.

The pattern-forming film 30 preferably contains nitrogen. In the above-mentioned transition metal silicide, nitrogen as a light element component has the effect of not lowering the refractive index compared to oxygen which is also a light element component. Therefore, by making the pattern-forming film 30 contain nitrogen, the film thickness can be thinned to obtain the desired phase difference (also called phase shift). In addition, the nitrogen content contained in the pattern-forming film 30 is preferably greater than 10 atomic %, and more preferably greater than 20 atomic %. On the other hand, the nitrogen content is preferably less than 60 atomic %, and more preferably less than 55 atomic %. By making the nitrogen content in the film 30 higher, the transmittance to the exposure light can be suppressed from becoming excessively high.

Furthermore, in addition to the above-mentioned oxygen and nitrogen, the pattern forming thin film 30 may also contain other light element components such as carbon and helium in order to control the reduction of film stress and/or the wet etching rate.

The pattern-forming film 30 may include multiple layers or a single layer. A pattern-forming film 30 including a single layer is preferred in that an interface is not easily formed in the pattern-forming film 30 and the cross-sectional shape is easily controlled. On the other hand, a pattern-forming film 30 including multiple layers is preferred in terms of ease of film formation. In order to ensure optical performance, the film thickness of the pattern-forming film 30 is preferably less than 200 nm, more preferably less than 180 nm, and further preferably less than 150 nm. In addition, in order to ensure the required transmittance, the film thickness of the pattern-forming film 30 is preferably greater than 50 nm, more preferably greater than 60 nm.

<<Transmittance and phase difference of pattern-forming film 30>> In the mask substrate 10 for manufacturing a display device of the present embodiment, the pattern-forming film 30 is preferably a phase shift film having optical properties of a transmittance of 1% to 80% and a phase difference of 140 degrees to 210 degrees relative to the representative wavelength of the exposure light (light with a wavelength of 405 nm: h-ray). The transmittance in this specification refers to the value converted based on the transmittance of the light-transmitting substrate as a reference (100%) unless otherwise specified.

When the pattern forming film 30 is a phase shift film, the pattern forming film 30 has the following functions: adjusting the reflectivity of light incident from the transparent substrate 20 side (hereinafter sometimes described as back reflectivity); and adjusting the transmittance and phase difference of exposure light.

The transmittance of the pattern-forming film 30 to the exposure light satisfies the value required as the pattern-forming film 30. For the light of a specific wavelength contained in the exposure light (hereinafter referred to as the representative wavelength), the transmittance of the pattern-forming film 30 is preferably 1% to 80%, more preferably 3% to 65%, and further preferably 5% to 60%. That is, when the exposure light is a composite light including light in a wavelength range of 313 nm to 436 nm, the pattern-forming film 30 has the above-mentioned transmittance to the light of the representative wavelength contained in the wavelength range. For example, when the exposure light is a composite light including i-rays, h-rays, and g-rays, the pattern-forming film 30 may have the above-mentioned transmittance to any one of the i-rays, h-rays, and g-rays. The representative wavelength may be, for example, h-rays having a wavelength of 405 nm. By having such characteristics for h-rays, when composite light including i-rays, h-rays and g-rays is used as exposure light, similar effects can be expected for the transmittance at the wavelengths of i-rays and g-rays.

Furthermore, when the exposure light is monochromatic light of a certain wavelength region selected by using a filter or the like in the wavelength range from 313 nm to 436 nm, and monochromatic light selected in the wavelength range from 313 nm to 436 nm, the pattern forming film 30 has the above-mentioned transmittance for the monochromatic light of a single wavelength.

The transmittance can be measured using a phase shift measurement device or the like.

The phase difference of the pattern-forming film 30 to the exposure light satisfies the value required as the pattern-forming film 30. The phase difference of the pattern-forming film 30 to the representative wavelength light contained in the exposure light is preferably 140 degrees to 210 degrees, more preferably 160 degrees to 200 degrees, and further preferably 170 degrees to 190 degrees. By this property, the phase of the representative wavelength light contained in the exposure light can be changed to 140 degrees to 210 degrees. Therefore, a phase difference of 140 degrees to 210 degrees is generated between the representative wavelength light passing through the pattern-forming film 30 and the representative wavelength light passing only through the light-transmitting substrate 20. That is, when the exposure light is a composite light including light in the wavelength range of 313 nm to 436 nm, the pattern-forming film 30 has the above-mentioned phase difference for light of a representative wavelength contained in the wavelength range. For example, when the exposure light is a composite light including i-rays, h-rays, and g-rays, the pattern-forming film 30 may have the above-mentioned phase difference for any of the i-rays, h-rays, and g-rays. The representative wavelength may be, for example, h-rays having a wavelength of 405 nm. By having such a characteristic for h-rays, when a composite light including i-rays, h-rays, and g-rays is used as the exposure light, a similar effect can be expected for the phase difference at the wavelengths of i-rays and g-rays.

The phase difference can be measured using a phase shift measurement device or the like.

The back reflectivity of the pattern-forming film 30 is 15% or less in the wavelength range of 365 nm to 436 nm, preferably 10% or less. Furthermore, when the exposure light includes j-rays (wavelength 313 nm), the back reflectivity of the pattern-forming film 30 is preferably 20% or less, more preferably 17% or less relative to the light in the wavelength range of 313 nm to 436 nm. It is more ideal to be 15% or less. Furthermore, the back reflectivity of the pattern-forming film 30 is 0.2% or more in the wavelength range of 365 nm to 436 nm, preferably 0.2% or more relative to the light in the wavelength range of 313 nm to 436 nm.

The back reflectivity can be measured using a spectrophotometer or the like.

The pattern forming thin film 30 can be formed by a known film forming method such as sputtering.

<Etching mask film 40> The mask base 10 for manufacturing a display device of the present embodiment is preferably an etching mask film 40 having an etching selectivity different from that of the pattern forming film 30 on the pattern forming film 30.

The etching mask film 40 is disposed on the upper side of the pattern forming film 30 and includes a material having etching resistance (having etching selectivity different from that of the pattern forming film 30) to the etching liquid for etching the pattern forming film 30. In addition, the etching mask film 40 may have a function of blocking the transmission of exposure light. Furthermore, the etching mask film 40 may have a function of reducing the film surface reflectivity so that the film surface reflectivity of the pattern forming film 30 relative to the light incident from the side of the pattern forming film 30 becomes less than 15% in the wavelength range of 350 nm to 436 nm.

The etching mask film 40 is preferably a chromium-based material containing chromium (Cr). The etching mask film 40 is more preferably a material containing chromium and substantially free of silicon. Substantially free of silicon means that the silicon content is less than 2% (except for the gradient composition region at the interface between the pattern forming thin film 30 and the etching mask film 40). More specifically, the chromium-based material includes a material containing chromium (Cr), or chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C). In addition, the chromium-based material includes a material containing chromium (Cr), at least one of oxygen (O), nitrogen (N), and carbon (C), and further including fluorine (F). For example, as a material constituting the etching mask film 40, Cr, CrO, CrN, CrF, CrCO, CrCN, CrON, CrCON, and CrCONF can be cited.

The etching mask film 40 can be formed by a known film forming method such as sputtering.

When the etching mask film 40 has the function of blocking the exposure light from passing through, the optical density of the exposure light in the portion where the pattern forming thin film 30 and the etching mask film 40 are laminated is preferably 3 or more, more preferably 3.5 or more, and further preferably 4 or more. The optical density can be measured using a spectrophotometer or an OD (Optical Density) meter.

The etching mask film 40 can be made into a single film with uniform composition according to its function. Alternatively, the etching mask film 40 can be made into a plurality of films with different compositions. Alternatively, the etching mask film 40 can be made into a single film with a composition that continuously changes along the thickness direction.

1 has an etching mask film 40 on the pattern forming thin film 30. The mask blank 10 of the present embodiment includes a mask blank 10 having the following structure: the etching mask film 40 is provided on the pattern forming thin film 30, and an anti-etching film is provided on the etching mask film 40.

<Manufacturing method of photomask base 10> Next, the manufacturing method of the photomask base 10 of the embodiment shown in FIG. 1 is described. The photomask base 10 shown in FIG. 1 is manufactured by performing the following pattern forming thin film forming step and etching mask film forming step. The photomask base 10 shown in FIG. 2 is manufactured by the pattern forming thin film forming step.

The following describes each step in detail.

<< Patterning Thin Film Formation Step>> First, prepare a light-transmitting substrate 20. The light-transmitting substrate 20 may be made of a glass material selected from synthetic quartz glass, quartz glass, aluminum silicate glass, sodium calcium glass, and low thermal expansion glass (such as _SiO2 - _TiO2 glass) as long as it is transparent to exposure light.

Next, the pattern forming thin film 30 is formed on the light-transmitting substrate 20 by sputtering.

The film formation of the pattern forming thin film 30 can be performed using a specific sputtering target in a specific sputtering gas atmosphere. The specific sputtering target is, for example, a transition metal silicide target containing a transition metal and silicon, or a transition metal silicon nitride target containing a transition metal, silicon, and nitrogen, wherein the transition metal and silicon are the main components of the material constituting the pattern forming thin film 30. The specific sputtering gas atmosphere is, for example, a sputtering gas atmosphere containing an inert gas including argon, or a sputtering gas atmosphere containing a mixed gas containing the above-mentioned inert gas, nitrogen, and a gas selected from the group consisting of oxygen, carbon dioxide, nitric oxide, and nitrogen dioxide. The formation of the pattern forming thin film 30 can be performed under the following conditions: the gas pressure in the film forming chamber during sputtering is 0.3 Pa to 2.0 Pa, preferably 0.43 Pa to 0.9 Pa. The side etching during pattern formation can be suppressed, and a high etching rate can be achieved. The atomic ratio of transition metal to silicon in the transition metal silicide target is preferably in the range of transition metal:silicon = 1:1 to 1:19 from the viewpoint of improving light resistance or adjusting transmittance.

The composition and thickness of the pattern-forming film 30 are adjusted in such a way that the pattern-forming film 30 has the above-mentioned phase difference and transmittance. The composition of the pattern-forming film 30 can be controlled by the content ratio of the elements constituting the sputtering target (for example, the ratio of the content of transition metal to the content of silicon), the composition and flow rate of the sputtering gas, etc. The thickness of the pattern-forming film 30 can be controlled by the sputtering power and the sputtering time, etc. In addition, the pattern-forming film 30 is preferably formed using a continuous (inline) sputtering device. When the sputtering device is a continuous sputtering device, the thickness of the pattern-forming film 30 can also be controlled by the transport speed of the substrate. In this way, the X-ray absorption spectrum of the pattern forming thin film 30 is controlled in such a way that it satisfies the required relationship (having an edge in the range of 400 eV to 402 eV, etc.). These film forming conditions are inherent to the film forming device and are appropriately adjusted in such a way that the formed thin film has the required optical characteristics.

When the pattern-forming thin film 30 includes a single film, the composition and flow rate of the sputtering gas are appropriately adjusted and the above-mentioned film forming process is performed only once. When the pattern-forming thin film 30 includes a plurality of films having different compositions, the composition and flow rate of the sputtering gas are appropriately adjusted and the above-mentioned film forming process is performed a plurality of times. The pattern-forming thin film 30 may also be formed using targets having different content ratios of elements constituting the sputtering target. When the film forming process is performed a plurality of times, the sputtering power applied to the sputtering target may be changed for each film forming process.

In this way, the mask substrate 10 of this embodiment can be obtained.

<<Etching mask film forming step>> The mask base 10 of the present embodiment may further have an etching mask film 40. The following etching mask film forming step is then performed. Furthermore, the etching mask film 40 preferably includes a material containing chromium.

After the pattern forming thin film forming step, a surface treatment is performed to adjust the surface oxidation state of the pattern forming thin film 30 as needed, and then an etching mask film 40 is formed on the pattern forming thin film 30 by sputtering. The etching mask film 40 is preferably formed using a continuous sputtering device. When the sputtering device is a continuous sputtering device, the thickness of the etching mask film 40 can also be controlled by the transport speed of the light-transmitting substrate 20.

The film formation of the etching mask film 40 can be carried out using a sputtering target containing chromium or a chromium compound (chromium oxide, chromium nitride, chromium carbide, chromium oxynitride, chromium nitride carbide, and chromium oxynitride carbide, etc.) in a sputtering gas atmosphere containing an inert gas or a sputtering gas atmosphere containing a mixed gas of an inert gas and an active gas. The inert gas can include, for example, at least one selected from the group consisting of helium, neon, argon, krypton, and xenon. The active gas can include at least one selected from the group consisting of oxygen, nitrogen, nitric oxide gas, nitrogen dioxide gas, carbon dioxide gas, hydrocarbon gas, and fluorine gas. Examples of hydrocarbon gas include methane gas, butane gas, propane gas, and styrene gas. By adjusting the gas pressure in the film forming chamber during sputtering, the etching mask film 40 can be formed into a columnar structure similar to the pattern forming film 30. This can suppress side etching during the pattern formation described below and achieve a high etching rate.

When the etching mask film 40 includes a single film with uniform composition, the composition and flow rate of the sputtering gas are not changed and the above film forming process is performed only once. When the etching mask film 40 includes a plurality of films with different compositions, the composition and flow rate of the sputtering gas are changed for each film forming process and the above film forming process is performed multiple times. When the etching mask film 40 includes a single film with a composition that changes continuously along the thickness direction, the composition and flow rate of the sputtering gas are changed as the film forming process passes, and the film forming process is performed only once.

Thus, the mask base 10 of the present embodiment having the etched mask film 40 can be obtained.

Furthermore, the photomask base 10 shown in FIG. 1 has an etching mask film 40 on the pattern forming thin film 30, so the etching mask film forming step is performed when manufacturing the photomask base 10. Also, when manufacturing the photomask base 10 having the etching mask film 40 on the pattern forming thin film 30 and having an anti-etching film on the etching mask film 40, the anti-etching film is formed on the etching mask film 40 after the etching mask film forming step. Also, when manufacturing the photomask base 10 shown in FIG. 2, that is, the photomask base 10 having an anti-etching film on the pattern forming thin film 30, the anti-etching film is formed after the pattern forming thin film forming step.

In the photomask base 10 of the embodiment shown in FIG1, an etching mask film 40 is formed on the pattern forming thin film 30. In addition, in the photomask base 10 of the embodiment shown in FIG2, a pattern forming thin film 30 is formed. In either case, the pattern forming thin film 30 has an X-ray absorption spectrum that satisfies the required relationship (having an edge in the range of 400 eV to 402 eV, etc.).

The photomask base 10 of the embodiment shown in FIG. 1 and FIG. 2 has high light resistance to exposure light with a wavelength including the ultraviolet region. Therefore, a pattern-forming thin film pattern 30a can be formed that can maintain the exposure transfer characteristics within the required range even after cumulative exposure to exposure light with a wavelength including the ultraviolet region. Therefore, by using the photomask base 10 of the present embodiment, the following transfer photomask 100 can be manufactured, which has high light resistance to exposure light with a wavelength including the ultraviolet region and can transfer the high-definition pattern-forming thin film pattern 30a with good precision.

<Manufacturing method of transfer mask 100> Next, the manufacturing method of the transfer mask 100 of this embodiment is described. The transfer mask 100 has the same technical features as the mask base 10. The matters related to the light-transmitting substrate 20, the pattern-forming film 30, and the etching mask film 40 in the transfer mask 100 are the same as those of the mask base 10.

Fig. 3 is a schematic diagram showing a method for manufacturing the transfer mask 100 according to the present embodiment. Fig. 4 is a schematic diagram showing another method for manufacturing the transfer mask 100 according to the present embodiment.

<<Manufacturing method of transfer mask 100 shown in FIG3> The manufacturing method of transfer mask 100 shown in FIG3 is a method of manufacturing transfer mask 100 using mask base 10 shown in FIG1. The manufacturing method of transfer mask 100 shown in FIG3 includes the following steps: preparing mask base shown in FIG1; forming an anti-etching film having a transfer pattern on etching mask film 40; performing wet etching using the anti-etching film as a mask to form a transfer pattern on etching mask film 40; and performing wet etching using the etching mask film (first etching mask film pattern 40a) having the transfer pattern as a mask to form a transfer pattern on pattern forming film 30. Furthermore, the transfer pattern in this specification refers to the one obtained by patterning at least one optical film formed on the light-transmitting substrate 20. The optical film can be a pattern-forming film 30 and/or an etching mask film 40, and can also include other films (light-shielding film, film for suppressing reflection, conductive film, etc.). That is, the transfer pattern can include a patterned pattern-forming film and/or an etching mask film, and can also include other patterned films.

Specifically, the manufacturing method of the transfer mask 100 shown in FIG3 is to form an anti-etching film on the etching mask film 40 of the mask base 10 shown in FIG1. Then, by drawing a desired pattern on the anti-etching film and developing it, an anti-etching film pattern 50 is formed (refer to FIG3 (a), the first step of forming the anti-etching film pattern 50). Then, the anti-etching film pattern 50 is used as a mask to wet-etch the etching mask film 40 to form an etching mask film pattern 40a on the pattern forming film 30 (refer to FIG3 (b), the first step of forming the etching mask film pattern 40a). Next, the pattern forming thin film 30 is wet-etched using the etching mask film pattern 40a as a mask to form a pattern forming thin film pattern 30a on the light-transmitting substrate 20 (refer to FIG. 3(c), the step of forming the pattern forming thin film pattern 30a). Then, the step of forming the second anti-etching film pattern 60 and the step of forming the second etching mask film pattern 40b may be further included (refer to FIG. 3(d) and (e)).

More specifically, in the step of forming the first anti-etching film pattern 50, first, an anti-etching film is formed on the etching mask film 40 of the mask base 10 of the present embodiment shown in FIG. 1. The anti-etching film material used is not particularly limited. For example, the anti-etching film can be sensitive to the following laser light, and the laser light has any wavelength selected from the wavelength range of 350 nm to 436 nm. In addition, the anti-etching film can be either positive or negative.

Then, a desired pattern is drawn on the anti-etching film using laser light having any wavelength selected from the wavelength region of 350 nm to 436 nm. The pattern drawn on the anti-etching film is the pattern formed on the pattern forming thin film 30. Examples of the pattern drawn on the anti-etching film include a line and space pattern and a hole pattern.

Then, the resist film is developed using a specific developer, and as shown in FIG. 3( a ), a first resist film pattern 50 is formed on the etching mask film 40 .

＜＜＜Step of forming the first etching mask film pattern 40a＞＞＞ In the step of forming the first etching mask film pattern 40a, first, the etching mask film 40 is etched using the first anti-etching film pattern 50 as a mask to form the first etching mask film pattern 40a. The etching mask film 40 may be formed of a chromium-based material containing chromium (Cr).

Then, as shown in Fig. 3(b), the first anti-etching film pattern 50 is peeled off using an anti-etching stripping solution or by ashing. Depending on the situation, the next step of forming the pattern-forming thin film pattern 30a may be performed without peeling off the first anti-etching film pattern 50.

＜＜＜Formation step of pattern-forming thin film pattern 30a＞＞＞ In the formation step of the first pattern-forming thin film pattern 30a, the first etching mask film pattern 40a is used as a mask to perform wet etching on the pattern-forming thin film 30, as shown in FIG. 3(c), to form a pattern-forming thin film pattern 30a. Examples of the pattern-forming thin film pattern 30a include line and space patterns and hole patterns. The etching liquid for etching the pattern-forming thin film 30 is not particularly limited as long as it can selectively etch the pattern-forming thin film 30. For example, an etching liquid containing ammonium hydrogen fluoride and hydrogen peroxide, or an etching liquid containing ammonium fluoride, phosphoric acid, and hydrogen peroxide, etc. can be cited.

In order to improve the cross-sectional shape of the pattern-forming thin film pattern 30a, wet etching is preferably performed for a longer time (overetching time) than the time until the light-transmitting substrate 20 is exposed in the pattern-forming thin film pattern 30a (appropriate etching time). As the overetching time, in consideration of the influence on the light-transmitting substrate 20, it is preferably set to a time obtained by adding 20% of the appropriate etching time to the appropriate etching time, and more preferably set to a time obtained by adding 10% of the appropriate etching time.

＜＜＜Step of forming the second anti-etching film pattern 60＞＞＞ In the step of forming the second anti-etching film pattern 60, first, an anti-etching film covering the first etching mask film pattern 40a is formed. The anti-etching film material used is not particularly limited. For example, it can be sensitive to the following laser light, which has any wavelength selected from the wavelength range of 350 nm to 436 nm. In addition, the anti-etching film can be either positive or negative.

Then, a desired pattern is drawn on the anti-corrosion film using laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm. The pattern drawn on the anti-corrosion film is a light shielding band pattern for shielding the peripheral area of the area where the pattern-forming thin film pattern 30a is formed, and a light shielding band pattern for shielding the central part of the pattern-forming thin film pattern 30a. Furthermore, according to the transmittance of the pattern-forming thin film 30 to the exposure light, the pattern drawn on the anti-corrosion film may also be a pattern without a light shielding band pattern for shielding the central part of the pattern-forming thin film pattern 30a.

Then, the anti-etching film is developed using a specific developer, and as shown in FIG. 3( d ), a second anti-etching film pattern 60 is formed on the first etching mask film pattern 40 a .

＜＜＜Step of forming the second etching mask film pattern 40b＞＞＞ In the step of forming the second etching mask film pattern 40b, the first etching mask film pattern 40a is etched using the second anti-etching film pattern 60 as a mask, as shown in FIG3(e), to form the second etching mask film pattern 40b. The first etching mask film pattern 40a can be formed of a chromium-based material containing chromium (Cr). The etching liquid for etching the first etching mask film pattern 40a is not particularly limited as long as it can selectively etch the first etching mask film pattern 40a. For example, an etching liquid containing ammonium nitrate and perchloric acid can be cited.

Then, the second anti-etching film pattern 60 is peeled off using an anti-etching stripping solution or by ashing.

Thus, the transfer mask 100 can be obtained. That is, the transfer pattern of the transfer mask 100 of the present embodiment may include the pattern forming thin film pattern 30a and the second etching mask film pattern 40b.

Furthermore, in the above description, the case where the etching mask film 40 has the function of blocking the transmission of the exposure light is described. In the case where the etching mask film 40 simply has the function of a hard mask when etching the pattern forming thin film 30, in the above description, the step of forming the second anti-etching film pattern 60 and the step of forming the second etching mask film pattern 40b are not performed. In this case, after the step of forming the pattern forming thin film pattern 30a, the first etching mask film pattern 40a is peeled off to produce the transfer mask 100. That is, the transfer pattern of the transfer mask 100 can be composed only of the pattern forming thin film pattern 30a.

According to the manufacturing method of the transfer mask 100 of the present embodiment, since the mask base 10 shown in FIG. 1 is used, the transfer mask 100 can be manufactured, which has high light resistance to exposure light of a wavelength including the ultraviolet region, and can transfer the high-definition pattern forming thin film pattern 30a with good precision. The transfer mask 100 manufactured in this way can correspond to the miniaturization of the line and space pattern and/or the contact hole. In addition, due to the high light resistance, a long service life as a transfer mask can be achieved.

＜＜Manufacturing method of transfer mask 100 shown in FIG. 4＞＞ The manufacturing method of transfer mask 100 shown in FIG. 4 is a method of manufacturing transfer mask 100 using mask base 10 shown in FIG. 2. The manufacturing method of transfer mask 100 shown in FIG. 4 includes the following steps: preparing mask base 10 shown in FIG. 2; and forming an anti-etching film on pattern forming film 30, and wet-etching pattern forming film 30 using the anti-etching film pattern formed by the anti-etching film as a mask to form a transfer pattern on light-transmitting substrate 20.

Specifically, in the manufacturing method of the transfer mask 100 shown in FIG. 4 , an anti-etching film is formed on the mask base 10. Then, by drawing a desired pattern on the anti-etching film and developing it, an anti-etching film pattern 50 is formed (FIG. 4(a), a step of forming the first anti-etching film pattern 50). Then, the anti-etching film pattern 50 is used as a mask to wet-etch the pattern-forming thin film 30, and a pattern-forming thin film pattern 30a is formed on the light-transmitting substrate 20 (FIG. 4(b) and (c), a step of forming the pattern-forming thin film pattern 30a).

More specifically, in the step of forming the anti-corrosion film pattern, first, an anti-corrosion film is formed on the pattern forming film 30 of the mask substrate 10 of the present embodiment shown in FIG. 2 . The anti-corrosion film material used is the same as described above. Furthermore, the pattern forming film 30 may be subjected to surface modification treatment as needed before the anti-corrosion film is formed so as to improve the adhesion between the pattern forming film 30 and the anti-corrosion film. Similarly to the above, after the anti-corrosion film is formed, a laser light having any wavelength selected from the wavelength region of 350 nm to 436 nm is used to draw the desired pattern on the anti-corrosion film. Then, the anti-corrosion film is developed using a specific developer, and as shown in FIG. 4( a), an anti-corrosion film pattern 50 is formed on the pattern forming film 30.

＜＜＜Formation step of pattern-forming thin film pattern 30a＞＞＞ In the formation step of the pattern-forming thin film pattern 30a, the anti-etching film pattern is used as a mask to etch the pattern-forming thin film 30, as shown in FIG4(b), to form the pattern-forming thin film pattern 30a. The pattern-forming thin film pattern 30a, the etching liquid for etching the pattern-forming thin film 30, and the over-etching time are the same as those described in the embodiment shown in FIG3 above.

Then, the anti-etching film pattern 50 is peeled off using an anti-etching agent stripping solution or by ashing ( FIG. 4( c )).

Thus, the transfer mask 100 can be obtained. In addition, the transfer pattern of the transfer mask 100 of the present embodiment is only composed of the pattern forming thin film pattern 30a, and can also include other film patterns. As other films, for example, a film for suppressing reflection, a conductive film, etc. can be cited.

According to the manufacturing method of the transfer mask 100 of the embodiment, by using the mask base 10 shown in FIG2 , the transfer mask 100 can be manufactured, which has high light resistance to exposure light having a wavelength including the ultraviolet region and can transfer the high-definition pattern forming thin film pattern 30a with good accuracy. The transfer mask 100 manufactured in this way can correspond to the miniaturization of the line and space pattern and/or the contact hole.

<Manufacturing method of display device> The manufacturing method of the display device of this embodiment is described. The manufacturing method of the display device of this embodiment includes the following exposure step: placing the transfer mask 100 for manufacturing the display device of the above-mentioned embodiment on the mask stage of the exposure device, and exposing and transferring the transfer pattern formed on the transfer mask 100 to the anti-etching film formed on the display device substrate.

Specifically, the manufacturing method of the display device of the present embodiment includes: a step of placing the transfer mask 100 manufactured using the above-mentioned mask base 10 on the mask stage of the exposure device (mask placement step); and a step of transferring the transfer pattern to the anti-etching film on the display device substrate (exposure step). Each step is described in detail below.

<<Loading step>> In the loading step, the transfer mask 100 of the present embodiment is loaded on the mask stage of the exposure device. Here, the transfer mask 100 is arranged to face the anti-etching film formed on the display device substrate via the projection optical system of the exposure device.

<<Pattern transfer step>> In the pattern transfer step, the transfer mask 100 is irradiated with exposure light to transfer the transfer pattern including the pattern-forming thin film pattern 30a to the anti-etching film formed on the display device substrate. The exposure light is a composite light including a plurality of wavelengths selected from the wavelength range of 313 nm to 436 nm, or a monochromatic light selected from a wavelength range of 313 nm to 436 nm by intercepting a filter or the like, or a monochromatic light emitted from a light source having a wavelength range of 313 nm to 436 nm. For example, the exposure light is a composite light including at least one of i-rays, h-rays, and g-rays, or a monochromatic light of i-rays. By using composite light as exposure light, the light intensity of the exposure light can be increased to improve productivity. Therefore, the manufacturing cost of the display device can be reduced.

According to the manufacturing method of the display device of the present embodiment, a high-definition display device with high resolution, fine line and space patterns and/or contact holes can be manufactured.

Furthermore, in the above embodiment, the case of using a mask base 10 having a pattern-forming film 30 and a transfer mask 100 having a pattern-forming film pattern 30a is described. The pattern-forming film 30 may be, for example, a phase-shift film having a phase-shift effect, or a light-shielding film. Therefore, the transfer mask 100 of the present embodiment includes a phase-shift mask having a phase-shift film pattern and a binary mask having a light-shielding film pattern. Furthermore, the mask base 10 of the present embodiment includes a phase-shift mask base and a binary mask base that are raw materials for the phase-shift mask and the binary mask. [Example]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

(Example 1) In order to manufacture the photomask base 10 of Example 1, first prepare a synthetic quartz glass substrate of 1214 size (1220 mm×1400 mm) as a light-transmitting substrate 20.

Then, the synthetic quartz glass substrate is placed on a tray (not shown) with its main surface facing downward, and is moved into a chamber of a continuous sputtering device.

In order to form the pattern forming thin film 30 on the main surface of the light-transmitting substrate 20, a mixed gas containing argon (Ar) gas and nitrogen (N ₂ ) gas is first introduced into the first chamber. In Example 1, the flow ratio of nitrogen (N ₂ ) gas to argon (Ar) gas (N ₂ /Ar) is 1.107. Then, using the first sputtering target containing titanium and silicon, titanium silicide nitride containing titanium, silicon and nitrogen is deposited on the main surface of the light-transmitting substrate 20 by reactive sputtering. The sputtering voltage at this time is 480 [V]. Thus, a pattern-forming thin film 30 with a thickness of 113 nm made of titanium silicide nitride is formed (Ti:Si:N:O=10.7:34.9:50.3:4.1 atomic % ratio). Here, the composition of the pattern-forming thin film 30 is the result obtained by measuring the thin film formed under the same film forming conditions as Example 1 by X-ray photoelectron spectroscopy (XPS). The following method for measuring the film composition is the same for other films (the following Examples 2, 3, and Comparative Examples 1 and 2 are the same). The ratio of the content of titanium in the pattern-forming thin film 30 to the total content of titanium and silicon is 0.235, which is greater than 0.05. Furthermore, the pattern-forming thin film 30 is a phase shift film having a phase shift effect.

Next, the light-transmitting substrate 20 with the pattern-forming thin film 30 is moved into the second chamber, and a mixed gas of argon (Ar) gas and nitrogen (N ₂ ) gas is introduced into the second chamber. Then, using a second sputtering target containing chromium, chromium nitride (CrN) containing chromium and nitrogen is formed on the pattern-forming thin film 30 by reactive sputtering. Next, in a state where the third chamber is set to a specific vacuum degree, a mixed gas of argon (Ar) gas and methane (CH ₄ ) gas is introduced, and using a third sputtering target containing chromium, chromium carbide (CrC) containing chromium and carbon is formed on CrN by reactive sputtering. Finally, in a state where the fourth chamber is set to a specific vacuum degree, a mixed gas of argon (Ar) gas and methane (CH ₄ ) gas and a mixed gas of nitrogen (N ₂ ) gas and oxygen (O ₂ ) gas are introduced, and a fourth sputtering target containing chromium is used to form chromium oxynitride carbide (CrCON) containing chromium, carbon, oxygen and nitrogen on CrC by reactive sputtering. As shown above, an etching mask film 40 having a laminated structure of a CrN layer, a CrC layer and a CrCON layer is formed on the pattern forming thin film 30.

Thus, a mask base 10 in which a pattern forming thin film 30 and an etching mask film 40 are formed on a light-transmitting substrate 20 is obtained.

The pattern-forming thin film of Example 1 was formed on the main surface of another synthetic quartz substrate (about 152 mm×about 152 mm), and another pattern-forming thin film was formed under the same film-forming conditions as in Example 1. Then, the pattern-forming thin film on the other synthetic quartz substrate was cut into a specific size to obtain a sample, and the sample was subjected to X-ray absorption fine structure analysis by X-ray absorption spectroscopy (electron yield method) to obtain an X-ray absorption spectrum. Specifically, it was performed by BL7U of the Aichi Synchrotron Radiation Center (the same applies to Examples 2, 3, and Comparative Examples 1 and 2 below).

FIG5 is a diagram showing an X-ray absorption spectrum obtained by X-ray absorption spectroscopy for the pattern forming film of the photomask base of Examples 1 to 3 and Comparative Examples 1 and 2 of the present invention (horizontal axis: X-ray energy incident on the film, vertical axis: X-ray absorption coefficient relative to the X-ray energy). FIG6 is an enlarged diagram of the main part of an X-ray absorption spectrum obtained by X-ray absorption spectroscopy for the pattern forming film of the photomask base of Examples 1 to 3 and Comparative Examples 1 and 2 of the present invention (horizontal axis: X-ray energy incident on the film, vertical axis: X-ray absorption coefficient relative to the X-ray energy). As shown in FIG. 5 and FIG. 6 , the X-ray absorption spectrum of Example 1 has an edge in the range of incident X-ray energy of 400 eV to 402 eV, and has an absorption end in the range of incident X-ray energy of 403 eV to 406 eV. Furthermore, as obtained from the values shown in FIG. 5, when the maximum value of the X-ray absorption coefficient at the absorption end of the X-ray absorption spectrum of the thin film 30 (the maximum value of the X-ray absorption coefficient within the range of incident X-ray energy of 403 eV to 406 eV, in Example 1, the X-ray absorption coefficient at the incident X-ray energy of 404.8 eV) is set as IA, and the maximum value of the X-ray absorption spectrum at the edge (the maximum value of the X-ray absorption coefficient within the range of incident X-ray energy of 400 eV to 401 eV, in Example 1, the X-ray absorption coefficient at the incident X-ray energy of 400.8 eV) is set as IP, IA/IP in Example 1 is 1.153, which satisfies the relationship of less than 1.45.

<Measurement of transmittance and phase difference> The transmittance (wavelength: 405 nm) and phase difference (wavelength: 405 nm) of the surface of the pattern-forming film 30 of the mask base 10 of Example 1 were measured. When measuring the transmittance and phase difference of the pattern-forming film 30, a substrate with an attached film of another pattern-forming film formed on the main surface of the above-mentioned other synthetic quartz glass substrate was used (the same is true in the following Examples 2, 3, and Comparative Examples 1 and 2). As a result, the transmittance of the other pattern-forming film (pattern-forming film 30) in Example 1 was 35.2%, and the phase difference was 140 degrees.

<Transfer mask 100 and its manufacturing method> The transfer mask 100 is manufactured using the mask base 10 of Example 1 manufactured by the above method. First, a photoresist film is coated on the etching mask film 40 of the mask base 10 using an anti-etching agent coating device.

Then, after heating and cooling steps, a photoresist film is formed.

Then, a laser patterning device is used to pattern the photoresist film, and after development and rinsing steps, an anti-etching film pattern with a hole pattern of 1.5 μm in diameter is formed on the etching mask film 40.

Then, the etching mask film 40 is wet-etched using a chromium etching solution containing ammonium nitrate and perchloric acid, using the anti-etching film pattern as a mask, to form a first etching mask film pattern 40a.

Then, the first etching mask film pattern 40a is used as a mask, and a titanium silicate etching solution obtained by diluting a mixture of ammonium hydrogen fluoride and hydrogen peroxide with pure water is used to wet-etch the pattern-forming thin film 30, thereby forming a pattern-forming thin film pattern 30a.

Then, the resist pattern is peeled off.

Then, a photoresist film is coated using an anti-etching agent coating device in a manner covering the first etching mask film pattern 40a.

Then, after heating and cooling steps, a photoresist film is formed.

Then, the photoresist film is patterned using a laser patterning device, and after development and rinsing steps, a second anti-etching film pattern 60 for forming a light-shielding band is formed on the first etching mask film pattern 40a.

Then, the first etching mask film pattern 40a formed in the transfer pattern forming region is wet-etched using the second anti-etching film pattern 60 as a mask using a chromium etching solution containing ammonium nitrate and perchloric acid.

Then, the second resist pattern 60 is peeled off.

Thus, the transfer mask 100 of Example 1 is obtained, which is formed on the transparent substrate 20 with a pattern forming thin film pattern 30a with an aperture of 1.5 μm in the transfer pattern forming area and a light shielding belt with a multilayer structure including the pattern forming thin film pattern 30a and the etching mask film pattern 40b.

<Cross-sectional shape of transfer mask 100> The cross-sectional shape of the obtained transfer mask 100 was observed using a scanning electron microscope. The pattern-forming thin film pattern 30a of the transfer mask 100 of Example 1 has a cross-sectional shape that is close to vertical. Therefore, the pattern-forming thin film pattern 30a formed in the transfer mask 100 of Example 1 has a cross-sectional shape that can fully exert the phase shift effect.

Based on the above, when the transfer mask 100 of Example 1 is set on the mask stage of the exposure device and the anti-etching film on the display device substrate is exposed and transferred, it can be said that the transfer pattern including a fine pattern less than 2.0 μm can be transferred with high precision.

<Light resistance> A sample was prepared in which the pattern forming film 30 used in the mask base 10 of Example 1 was formed on a light-transmitting substrate 20. The pattern forming film 30 of the sample of Example 1 was irradiated with light from a metal halide light source including ultraviolet light of a wavelength of 405 nm in such a manner that the total irradiation amount became 10 kJ/ ^cm2 . The transmittance was measured before and after the irradiation with specific ultraviolet light, and the change in transmittance [(transmittance after ultraviolet irradiation) - (transmittance before ultraviolet irradiation)] was calculated to evaluate the light resistance of the pattern forming film 30. The transmittance was measured using a spectrophotometer.

FIG7 is a graph showing the relationship between IA/IP and the change in transmittance of the pattern-forming film of the photomask base of Examples 1 to 3 and Comparative Examples 1 and 2 of the present invention. As shown in FIG7 , in Example 1, the change in transmittance before and after ultraviolet irradiation is good at 0.34%. From the above, it can be seen that the pattern-forming film of Example 1 is a film with high enough light resistance for practical use.

Based on the above, it is clear that the pattern-forming film of Example 1 is an unprecedented excellent product that meets the required optical properties (transmittance, phase difference) and meets the requirement of having high light resistance to exposure light with a wavelength including the ultraviolet region.

(Example 2) The mask base 10 of Example 2 is manufactured by the same steps as the mask base 10 of Example 1, except that the pattern-forming thin film 30 is manufactured in the following manner. The method for forming the pattern-forming thin film 30 of Example 2 is described as follows. In order to form the pattern-forming thin film 30 on the main surface of the light-transmitting substrate 20, a mixed gas containing argon (Ar) gas and nitrogen ( _N2 ) gas is first introduced into the first chamber. In Example 2, the flow ratio ( _N2 /Ar) of nitrogen ( _N2 ) gas to argon (Ar) gas is 1.107. Then, using a first sputtering target containing titanium and silicon, a nitride of titanium silicide containing titanium, silicon and nitrogen is deposited on the main surface of the light-transmitting substrate 20 by reactive sputtering. Thus, a pattern-forming thin film 30 with a thickness of 124 nm made of titanium silicide nitride (Ti:Si:N:O=11.0:33.8:50.1:5.1 atomic % ratio) is formed. The sputtering voltage at this time is 515 [V]. The composition of the thin film 30 in Example 2 is almost the same as that of the thin film 30 in Example 1. The ratio of the content of titanium in the pattern-forming thin film 30 to the total content of titanium and silicon is 0.05 or more. Then, an etching mask film 40 is formed in the same manner as in Example 1.

Furthermore, another pattern-forming thin film is formed on the main surface of another synthetic quartz substrate under the same film-forming conditions as in the above-mentioned Example 2. Then, the pattern-forming thin film on the other synthetic quartz substrate is cut into a specific size to obtain a sample, and the sample is subjected to X-ray absorption fine structure analysis by X-ray absorption spectroscopy (electron yield method) in the same manner as in Example 1 to obtain an X-ray absorption spectrum. As shown in Figures 5 and 6, the X-ray absorption spectrum of Example 2 has an edge in the range of incident X-ray energy of 400 eV to 402 eV, and has an absorption end in the range of incident X-ray energy of 403 eV to 406 eV. The shape of the X-ray absorption spectrum in Example 2 is the same as that in Example 1. Furthermore, as can be found from the values shown in Figures 5 and 6, IA/IP in Example 2 is 1.128 (in Example 2, IA is the X-ray absorption coefficient at an incident X-ray energy of 405.1 eV, and IP is the X-ray absorption coefficient at an incident X-ray energy of 401.0 eV), which satisfies the relationship of less than 1.45.

<Measurement of transmittance and phase difference> The transmittance (wavelength: 405 nm) and phase difference (wavelength: 405 nm) of the surface of the pattern forming film 30 of the mask base 10 of Example 2 were measured. The results showed that the transmittance of the pattern forming film 30 in Example 2 was 31.1% and the phase difference was 147 degrees.

<Transfer mask 100 and its manufacturing method> Using the mask base 10 of Example 2 manufactured by the above method, the transfer mask 100 is manufactured in the same steps as Example 1, and the transfer mask 100 of Example 2 is manufactured by forming a pattern forming thin film pattern 30a with an aperture of 1.5 μm in the transfer pattern forming area on the transparent substrate 20, and a light shielding belt having a multilayer structure including the pattern forming thin film pattern 30a and the etching mask film pattern 40b.

<Cross-sectional shape of transfer mask 100> The cross-sectional shape of the obtained transfer mask 100 was observed using a scanning electron microscope. The pattern-forming thin film pattern 30a of the transfer mask 100 of Example 2 has a cross-sectional shape that is close to vertical. Therefore, the pattern-forming thin film pattern 30a formed in the transfer mask 100 of Example 2 has a cross-sectional shape that can fully exert the phase shift effect.

Based on the above, it can be said that when the transfer mask 100 of Example 2 is set on the mask stage of the exposure device to perform exposure transfer on the anti-etching film on the display device substrate, the transfer pattern including a fine pattern less than 2.0 μm can be transferred with high precision.

<Light resistance> A sample was prepared in which the pattern forming film 30 used in the mask base 10 of Example 2 was formed on a light-transmitting substrate 20. The pattern forming film 30 of the sample of Example 2 was irradiated with light from a metal halide light source including ultraviolet light of a wavelength of 405 nm in such a manner that the total irradiation amount became 10 kJ/ ^cm2 . The transmittance was measured before and after the irradiation of specific ultraviolet light, and the change in transmittance [(transmittance after ultraviolet irradiation) - (transmittance before ultraviolet irradiation)] was calculated to evaluate the light resistance of the pattern forming film 30. The transmittance was measured using a spectrophotometer.

As shown in Fig. 7, in Example 2, the change in transmittance before and after ultraviolet irradiation is good, which is 0.42%. From the above, it can be seen that the pattern-forming film of Example 2 is a film with high enough light resistance for practical use.

Based on the above, it is clear that the pattern-forming film of Example 2 is an unprecedented excellent product that meets the required optical properties (transmittance, phase difference) and meets the requirement of having high light resistance to exposure light with a wavelength including the ultraviolet region.

(Example 3) The mask base 10 of Example 3 is manufactured by the same steps as the mask base 10 of Example 1, except that the pattern-forming thin film 30 is manufactured in the following manner. The method for forming the pattern-forming thin film 30 of Example 3 is described as follows. In order to form the pattern-forming thin film 30 on the main surface of the light-transmitting substrate 20, first, a mixed gas containing argon (Ar) gas and nitrogen ( _N2 ) gas is introduced into the first chamber. In Example 3, the flow ratio ( _N2 /Ar) of nitrogen ( _N2 ) gas to argon (Ar) gas is 1.111. Then, using a first sputtering target containing titanium and silicon, a nitride of titanium silicide containing titanium, silicon and nitrogen is deposited on the main surface of the light-transmitting substrate 20 by reactive sputtering. Thus, a pattern forming thin film 30 with a thickness of 142 nm made of titanium silicide nitride is formed. The composition of the thin film 30 in Example 3 is almost the same as that of the thin film 30 in Example 1. The ratio of the content of titanium in the pattern forming thin film 30 to the total content of titanium and silicon is 0.05 or more. Then, an etching mask film 40 is formed in the same manner as in Example 1.

Furthermore, another pattern-forming thin film is formed on the main surface of another synthetic quartz substrate under the same film-forming conditions as in the above-mentioned Example 3. Then, the pattern-forming thin film on the other synthetic quartz substrate is cut into a specific size to obtain a sample, and the sample is subjected to X-ray absorption fine structure analysis by X-ray absorption spectroscopy (electron yield method) in the same manner as in Example 1 to obtain an X-ray absorption spectrum. As shown in FIG5 , the X-ray absorption spectrum of Example 3 has an edge in the range of incident X-ray energy of 400 eV to 402 eV, and has an absorption end in the range of incident X-ray energy of 403 eV to 406 eV. The shape of the X-ray absorption spectrum in Example 3 has characteristics similar to that of the X-ray absorption spectrum in Example 1. In addition, as obtained from the values shown in Figures 5 and 6, IA/IP in Example 3 is 1.363 (in Example 3, IA is the X-ray absorption coefficient at an incident X-ray energy of 405.1 eV, and IP is the X-ray absorption coefficient at an incident X-ray energy of 401.0 eV), which satisfies the relationship of less than 1.45.

<Measurement of transmittance and phase difference> The transmittance (wavelength: 405 nm) and phase difference (wavelength: 405 nm) of the surface of the pattern forming film 30 of the mask base 10 of Example 3 were measured. The results showed that the transmittance of the pattern forming film 30 in Example 3 was 29.1% and the phase difference was 180 degrees.

<Transfer mask 100 and its manufacturing method> The transfer mask 100 is manufactured by the same steps as in Example 1 using the mask base 10 of Example 3 manufactured by the above method, and the transfer mask 100 of Example 3 is obtained, which is formed on the light-transmitting substrate 20 with a pattern-forming thin film pattern 30a with an aperture of 1.5 μm in the transfer pattern forming area, and a light-shielding belt having a multilayer structure including the pattern-forming thin film pattern 30a and the etching mask film pattern 40b.

<Cross-sectional shape of transfer mask 100> The cross-sectional shape of the obtained transfer mask 100 was observed using a scanning electron microscope. The pattern-forming thin film pattern 30a of the transfer mask 100 of Example 3 has a cross-sectional shape that is close to vertical. Therefore, the pattern-forming thin film pattern 30a formed in the transfer mask 100 of Example 3 has a cross-sectional shape that can fully exert the phase shift effect.

Based on the above, it can be said that when the transfer mask 100 of Example 3 is set on the mask stage of the exposure device and the anti-etching film on the display device substrate is exposed and transferred, the transfer pattern including a fine pattern less than 2.0 μm can be transferred with high precision.

<Light resistance> A sample of the pattern forming film 30 used in the mask base 10 of Example 3 was prepared by forming it on a light-transmitting substrate 20. The pattern forming film 30 of the sample of Example 3 was irradiated with light from a metal halide light source including ultraviolet light of a wavelength of 405 nm in such a manner that the total irradiation amount became 10 kJ/ ^cm2 . The transmittance was measured before and after the irradiation of specific ultraviolet light, and the change in transmittance [(transmittance after ultraviolet irradiation) - (transmittance before ultraviolet irradiation)] was calculated to evaluate the light resistance of the pattern forming film 30. The transmittance was measured using a spectrophotometer.

As shown in Fig. 7, the change in transmittance before and after ultraviolet irradiation in Example 3 is good, at 0.36%. As can be seen from the above, the pattern-forming film of Example 3 is a film with high enough light resistance for practical use.

Based on the above, it is clear that the pattern-forming film of Example 3 is an unprecedented excellent product that meets the required optical properties (transmittance, phase difference) and meets the requirement of having high light resistance to exposure light with a wavelength including the ultraviolet region.

(Comparative Example 1) The photomask base 10 of Comparative Example 1 is manufactured by the same steps as the photomask base 10 of Example 1, except that the pattern forming thin film 30 is manufactured in the following manner. The method for forming the pattern forming thin film 30 of Comparative Example 1 is as follows. In order to form the pattern forming thin film 30 on the main surface of the light-transmitting substrate 20, first, a mixed gas containing argon (Ar) gas and nitrogen ( _N2 ) gas is introduced into the first chamber. In Comparative Example 1, the flow ratio ( _N2 /Ar) of nitrogen ( _N2 ) gas to argon (Ar) gas is 0.393. Then, using the first sputtering target containing titanium and silicon, titanium silicide nitride containing titanium, silicon and nitrogen is deposited on the main surface of the light-transmitting substrate 20 by reactive sputtering. Thus, a pattern-forming thin film 30 with a film thickness of 118 nm made of titanium silicide nitride is formed (Ti:Si:N:O=11.1:34.0:50.7:4.2 atomic % ratio). Thus, the composition of the thin film 30 in Comparative Example 1 is almost the same as the composition of the thin film 30 in Example 1. Then, an etching mask film 40 is formed in the same manner as in Example 1.

Furthermore, another pattern-forming thin film is formed on the main surface of another synthetic quartz substrate under the same film-forming conditions as those of the above-mentioned comparative example 1. Then, the pattern-forming thin film on the other synthetic quartz substrate is cut into a specific size to obtain a sample, and the sample is subjected to X-ray absorption fine structure analysis by X-ray absorption spectroscopy (electron yield method) in the same manner as in Example 1 to obtain an X-ray absorption spectrum. As shown in FIG5 , the X-ray absorption spectrum of comparative example 1 has an absorption edge in the range of incident X-ray energy of 403 eV to 406 eV, but has no edge in the range of incident X-ray energy of 400 eV to 402 eV (substantially monotonically increasing). As shown in FIG6 , the shape of the X-ray absorption spectrum near the edge in Comparative Example 1 is very different from that in Example 1. In addition, as obtained from the values shown in FIG5 and FIG6 , IA/IP in Comparative Example 1 is 1.543 (in Comparative Example 1, IA is the X-ray absorption coefficient at an incident X-ray energy of 405.0 eV, and IP is the X-ray absorption coefficient at an incident X-ray energy of 401.0 eV), which does not satisfy the relationship of less than 1.45.

<Measurement of transmittance and phase difference> The transmittance (wavelength: 405 nm) and phase difference (wavelength: 405 nm) of the surface of the pattern forming film 30 of the mask base 10 of Example 1 were measured. The results showed that the transmittance of the pattern forming film 30 in Example 1 was 31.7% and the phase difference was 154 degrees.

<Transfer mask 100 and its manufacturing method> The transfer mask 100 is manufactured by the same steps as in Example 1 using the mask base 10 of Comparative Example 1 manufactured by the above method, and the transfer mask 100 of Comparative Example 1 is obtained, which is formed on the light-transmitting substrate 20 with a pattern-forming thin film pattern 30a having an aperture of 1.5 μm in the transfer pattern forming area, and a light-shielding belt having a multilayer structure including the pattern-forming thin film pattern 30a and the etching mask film pattern 40b.

<Cross-sectional shape of transfer mask 100> The cross-sectional shape of the obtained transfer mask 100 was observed using a scanning electron microscope. The pattern-forming thin film pattern 30a of the transfer mask 100 of Comparative Example 1 has a cross-sectional shape that is close to vertical. Therefore, the pattern-forming thin film pattern 30a formed in the transfer mask 100 of Comparative Example 1 has a cross-sectional shape that can fully exert the phase shift effect.

Based on the above, it can be said that when the transfer mask 100 of Comparative Example 1 is set on the mask stage of the exposure device and the anti-etching film on the display device substrate is exposed and transferred, the transfer pattern including a fine pattern less than 2.0 μm can be transferred with high precision.

<Light resistance> A sample was prepared in which the pattern forming film 30 used in the mask base 10 of Comparative Example 1 was formed on a light-transmitting substrate 20. The pattern forming film 30 of the sample of Comparative Example 1 was irradiated with light from a metal halide light source including ultraviolet light of a wavelength of 405 nm in such a manner that the total irradiation amount became 10 kJ/cm ^2. The transmittance was measured before and after the irradiation of specific ultraviolet light, and the change in transmittance [(transmittance after ultraviolet irradiation) - (transmittance before ultraviolet irradiation)] was calculated to evaluate the light resistance of the pattern forming film 30. The transmittance was measured using a spectrophotometer.

As shown in FIG. 7 , in Comparative Example 1, the change in transmittance before and after ultraviolet irradiation is 2.32%, which is beyond the allowable range (within 2%). As can be seen from the above, the pattern forming film of Comparative Example 1 does not have sufficient light resistance for practical use.

(Comparative Example 2) The photomask base 10 of Comparative Example 2 is manufactured by the same steps as the photomask base 10 of Example 1, except that the pattern forming thin film 30 is manufactured in the following manner. The method for forming the pattern forming thin film 30 of Comparative Example 2 is as follows. In order to form the pattern forming thin film 30 on the main surface of the light-transmitting substrate 20, first, a mixed gas containing argon (Ar) gas and nitrogen ( _N2 ) gas is introduced into the first chamber. In Comparative Example 2, the flow ratio ( _N2 /Ar) of nitrogen ( _N2 ) gas to argon (Ar) gas is 0.383. Then, using the first sputtering target containing titanium and silicon, titanium silicide nitride containing titanium, silicon and nitrogen is deposited on the main surface of the light-transmitting substrate 20 by reactive sputtering. Thus, a pattern-forming thin film 30 with a film thickness of 180 nm made of titanium silicide nitride (Ti:Si:N:O=12.1:35.5:50.3:2.1 atomic % ratio) is formed. The composition of the thin film 30 in Comparative Example 2 is almost the same as that of the thin film 30 in Example 1. Then, an etching mask film 40 is formed in the same manner as in Example 1.

Furthermore, another pattern-forming thin film is formed on the main surface of another synthetic quartz substrate under the same film-forming conditions as those in the above-mentioned comparative example 2. Subsequently, the pattern-forming thin film on the other synthetic quartz substrate is cut into a specific size to obtain a sample, and the sample is subjected to X-ray absorption fine structure analysis by X-ray absorption spectroscopy (electron yield method) in the same manner as in Example 1 to obtain an X-ray absorption spectrum. As shown in FIG5 , the X-ray absorption spectrum of comparative example 2 has an absorption edge in the range of incident X-ray energy of 403 eV to 406 eV, but has no edge in the range of incident X-ray energy of 400 eV to 402 eV (substantially monotonically increasing). As shown in FIG6, the shape of the X-ray absorption spectrum near the edge in Comparative Example 2 is very different from that in Example 1. In addition, as obtained from the values shown in FIG5 and FIG6, IA/IP in Comparative Example 2 is 1.478 (in Comparative Example 2, IA is the X-ray absorption coefficient at an incident X-ray energy of 404.7 eV, and IP is the X-ray absorption coefficient at an incident X-ray energy of 401.0 eV), which does not satisfy the relationship of less than 1.45.

<Measurement of transmittance and phase difference> The transmittance (wavelength: 405 nm) and phase difference (wavelength: 405 nm) of the surface of the pattern forming film 30 of the mask base 10 of Example 2 were measured. The results showed that the transmittance of the pattern forming film 30 in Example 2 was 21.2% and the phase difference was 235 degrees.

<Transfer mask 100 and its manufacturing method> The transfer mask 100 of Comparative Example 2 is manufactured by the same steps as Example 1 using the mask base 10 of Comparative Example 2 manufactured by the above method, and the transfer mask 100 of Comparative Example 2 is obtained, which is formed on the transparent substrate 20 with a pattern forming thin film pattern 30a with an aperture of 1.5 μm in the transfer pattern forming area, and a light shielding belt having a multilayer structure including the pattern forming thin film pattern 30a and the etching mask film pattern 40b.

<Cross-sectional shape of transfer mask 100> The cross-sectional shape of the obtained transfer mask 100 was observed using a scanning electron microscope. The pattern-forming thin film pattern 30a of the transfer mask 100 of Comparative Example 2 has a cross-sectional shape that is close to vertical. Therefore, the pattern-forming thin film pattern 30a formed in the transfer mask 100 of Comparative Example 2 has a cross-sectional shape that can fully exert the phase shift effect.

Based on the above, it can be said that when the transfer mask 100 of Comparative Example 2 is set on the mask stage of the exposure device and the anti-etching film on the display device substrate is exposed and transferred, the transfer pattern including a fine pattern less than 2.0 μm can be transferred with high precision.

<Light resistance> A sample was prepared in which the pattern forming film 30 used in the mask base 10 of Comparative Example 2 was formed on a light-transmitting substrate 20. The pattern forming film 30 of the sample of Comparative Example 2 was irradiated with light from a metal halide light source including ultraviolet light of a wavelength of 405 nm in such a manner that the total irradiation amount became 10 kJ/cm ^2. The transmittance was measured before and after the irradiation with specific ultraviolet light, and the change in transmittance [(transmittance after ultraviolet irradiation) - (transmittance before ultraviolet irradiation)] was calculated to evaluate the light resistance of the pattern forming film 30. The transmittance was measured using a spectrophotometer.

As shown in FIG. 7 , in Comparative Example 2, the change in transmittance before and after ultraviolet irradiation is 3.30%, which is beyond the allowable range (within 2%). As can be seen from the above, the pattern forming film of Comparative Example 2 does not have sufficient light resistance for practical use.

In the above-mentioned embodiment, the transfer mask 100 for display device manufacturing and the mask base 10 for manufacturing the transfer mask 100 for display device manufacturing are described, but are not limited thereto. The mask base 10 and/or the transfer mask 100 of the present invention can also be applied to semiconductor device manufacturing, MEMS (microelectromechanical system) manufacturing, and printed circuit board manufacturing. In addition, the present invention can also be applied to a binary mask base having a light-shielding film as a pattern-forming thin film 30 and a binary mask having a light-shielding film pattern.

Furthermore, in the above-mentioned embodiment, an example in which the size of the light-transmitting substrate 20 is 1214 mm (1220 mm×1400 mm×13 mm) is described, but it is not limited thereto. In the case of a mask base 10 for manufacturing a display device, a large-size light-transmitting substrate 20 can be used, and the size of the light-transmitting substrate 20 is that the length of one side of the main surface is 300 mm or more. The size of the light-transmitting substrate 20 used in the mask base 10 for manufacturing a display device is, for example, 330 mm×450 mm or more and 2280 mm×3130 mm or less.

Furthermore, in the case of a mask base 10 for semiconductor device manufacturing, MEMS manufacturing, or printed circuit board manufacturing, a small size light-transmitting substrate 20 can be used, wherein the length of one side of the light-transmitting substrate 20 is 9 inches or less. The size of the light-transmitting substrate 20 used in the mask base 10 for the above-mentioned purposes is, for example, not less than 63.1 mm×63.1 mm and not more than 228.6 mm×228.6 mm. Generally speaking, as a light-transmitting substrate 20 for a transfer mask 100 for semiconductor device manufacturing and MEMS manufacturing, a 6025 size (152 mm×152 mm) or a 5009 size (126.6 mm×126.6 mm) can be used. In general, as the light-transmitting substrate 20 of the transfer mask 100 used for manufacturing a printed circuit board, a 7012 size (177.4 mm×177.4 mm) or 9012 size (228.6 mm×228.6 mm) substrate can be used.

10: Photomask base 20: Translucent substrate 30: Thin film for pattern formation 30a: Thin film pattern 40: Etching mask film 40a: First etching mask film pattern 40b: Second etching mask film pattern 50: First anti-etching film pattern 60: Second anti-etching film pattern 100: Transfer mask

FIG. 1 is a cross-sectional schematic diagram showing the film structure of the mask base of the embodiment of the present invention. FIG. 2 is a cross-sectional schematic diagram showing another film structure of the mask base of the embodiment of the present invention. FIG. 3(a) to (e) are cross-sectional schematic diagrams showing the manufacturing steps of the transfer mask of the embodiment of the present invention. FIG. 4(a) to (c) are cross-sectional schematic diagrams showing another manufacturing step of the transfer mask of the embodiment of the present invention. FIG. 5 is a diagram showing the X-ray absorption spectrum (horizontal axis: X-ray energy incident on the film, vertical axis: X-ray absorption coefficient of the film relative to the X-ray energy) obtained by X-ray absorption spectroscopy for the pattern forming film of the mask base of Examples 1 to 3 and Comparative Examples 1 and 2 of the present invention. FIG6 is an enlarged view of the main part of the X-ray absorption spectrum (horizontal axis: X-ray energy incident on the film, vertical axis: X-ray absorption coefficient of the film relative to the X-ray of the energy) obtained by X-ray absorption spectroscopy for the pattern forming film of the photomask base of Examples 1 to 3 and Comparative Examples 1 and 2 of the present invention. FIG7 is a graph showing the relationship between IA/IP and the change of transmittance of the pattern forming film of the photomask base of Examples 1 to 3 and Comparative Examples 1 and 2 of the present invention.

Claims (16)

A photomask base, characterized in that: it is a thin film for pattern formation on a light-transmitting substrate, and the thin film contains transition metal and silicon, and the X-ray absorption spectrum of the thin film obtained by X-ray absorption spectroscopy has an edge in the range of incident X-ray energy of 400 eV to 402 eV. The mask substrate of claim 1, wherein the X-ray absorption spectrum of the above-mentioned film has an absorption edge in the range of incident X-ray energy of not less than 403 eV and not more than 406 eV. In the mask substrate of claim 2, when the maximum value of the X-ray absorption coefficient in front of the edge is set as IP and the maximum value of the X-ray absorption coefficient at the absorption end is set as IA, IA/IP satisfies a relationship below 1.45. A mask substrate as claimed in claim 1, wherein the above-mentioned film further contains nitrogen. A mask substrate as claimed in claim 1, wherein the thin film contains at least titanium as the transition metal. The photomask substrate of claim 1, wherein the ratio of the content of transition metal in the above-mentioned film to the total content of transition metal and silicon is greater than 0.05. The mask base of claim 1 has an etching mask film on the thin film, the etching selectivity of which is different from that of the thin film. A mask substrate as claimed in claim 7, wherein the etching mask film contains chromium. A transfer mask, characterized in that: it is a thin film with a transfer pattern formed on a light-transmitting substrate, and the thin film contains transition metal and silicon, and the X-ray absorption spectrum of the thin film obtained by X-ray absorption spectroscopy has an edge in the range of incident X-ray energy of 400 eV to 402 eV. A transfer mask as claimed in claim 9, wherein the X-ray absorption spectrum of the above-mentioned film has an absorption edge in the range of incident X-ray energy of not less than 403 eV and not more than 406 eV. In the transfer mask of claim 10, when the maximum value of the X-ray absorption coefficient at the front of the edge is set to IP and the maximum value of the X-ray absorption coefficient at the absorption end is set to IA, IA/IP satisfies a relationship of less than 1.45. As in claim 9, the transfer mask, wherein the above-mentioned film further contains nitrogen. As in the transfer mask of claim 9, the above-mentioned film contains at least titanium as the above-mentioned transition metal. As in claim 9, the transfer mask, wherein the ratio of the content of transition metal in the above-mentioned film to the total content of transition metal and silicon is greater than 0.05. A method for manufacturing a transfer mask, characterized in that it includes the following steps: Preparing a mask substrate as claimed in claim 7 or 8; Forming an anti-etching film having a transfer pattern on the etching mask film; Performing wet etching using the anti-etching film as a mask to form a transfer pattern on the etching mask film; and Performing wet etching using the etching mask film having the transfer pattern as a mask to form a transfer pattern on the thin film. A method for manufacturing a display device, characterized by comprising the following steps: Placing a transfer mask as described in any one of claims 9 to 14 on a mask stage of an exposure device; and Irradiating the transfer mask with exposure light to transfer a transfer pattern to an anti-etching film provided on a substrate for the display device.