JPS60238829A - Formation of pattern - Google Patents

Abstract

PURPOSE:To form a minute pattern with high dimensional precision by forming a photosensitive layer contg. a photosensitive diazonium salt on a resist film and patternwise exposing both of the resist film and said layer to rays to which both are sensitive. CONSTITUTION:The substrate, such as a wafer, is coated with an ordinary resist soln. and dried to form a resist film, and further, it is coated with a diazo photosensitive soln. prepared by dissolving the photosensitive diazonium salt and a binder resin in a proper solvent, with a spinner or the like, and dried to obtain a diazo photosensitive film. As said diazonium salt, ones represented by the formula (R1, R2 are each alkyl, and both may form a ring together with C or O; Y, Z are each H, alkyl, or aryl; and X is an anion, such as halogen ion) are suitable. Then, both of the resist film and the diazo photosensitive layer are exposed.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a pattern forming method suitable for microfabrication,
More specifically, the present invention relates to a pattern forming method for obtaining fine patterns with stable dimensional accuracy using a simple method.

[Technical background of the invention and its problems, 1 The density of integrated circuits is increasing at a rate of four times every two to three years, and along with this, the dimensions of patterns required for microfabrication of elements are also increasing. It is becoming increasingly finer, and it is required to control the dimensional viscosity to Wl and density. In response to these demands, efforts are being made to develop pattern-forming technology that can form fine patterns and maintain dimensional accuracy even in the face of process variations. It is progressing.

Incidentally, one of the factors that limits the resolution necessary for forming fine patterns is a diffraction phenomenon based on the wave nature of light beams (particle beams). Diffraction theory indicates that the resolution of an exposure system increases as the wavelength of the light beam (particle beam) used becomes shorter. For this reason, far ultraviolet light (wavelength 200-300n)
Exposure technologies using RL, X-rays, and electron beams require expensive equipment and have problems in mass production.Currently, among these, electron beam exposure technology is the only method used to form mask patterns for wafer processing. used in

On the other hand, if the conventional ultraviolet exposure technology (wavelength 300 to 450 nm) can be applied, the conventional technology can be used as is, which is extremely advantageous in terms of mass production and cost efficiency. In fact, there is still ample room for improvement in the application of ultraviolet exposure technology to submicron and micro 5-ill applications. Improvement of ultraviolet exposure technology from the viewpoint of pattern miniaturization - Two necessary elemental technologies are as follows.

■ Shortening the wavelength of the light beam used in the imaging system ■ Using an optical system with a large numerical aperture ■ Increasing the γ value (= J contrast) of the resist ■ Thinning the resist film ■ Photobleaching on the resist film Install the thin film of lens 1.
Improve the optical contrast of C with respect to ~.

(2) and (2) are mainly concerned with improvements to the -C optical system.An improvement in resolution can be expected from optical theory, but at short wavelengths, the transmittance of the lens decreases, so the amount of light is reduced by 4-minutes. I can't get it. Furthermore, if the number of frontages is increased too much, the depth of focus becomes shallow and there is a problem that the wafer becomes susceptible to irregularities and steps on the surface of the wafer. On the other hand, ■, ■, and ■ relate to improvement of the resist itself.

When the γ value is increased, the resolution is improved, a sharp pattern can be obtained, and there is also an advantage that the film does not perish during development. Methods for increasing the γ value cannot be generalized because they directly depend on the chemical structure of the resist material, but they include: ■ narrowing the molecular weight distribution of the polymer material, and ■ absorbing the light that sensitizes the resist into the resist material. (Japanese Patent Laid-Open No. 52-130286)
> have been proposed. However, the method (■) is usually applied to cross-linked resists, but there is a theoretical limit to the γ value that can be achieved, and the method (■) is also effective, but the resist function is affected, so adding a fading material is necessary. Quantities are limited. Due to these circumstances, there is a limit to the improvement of the γ value.

Furthermore, when the resist film thickness is reduced, blurring caused by light scattering phenomenon is reduced, and resolution is improved. However, if the film is made too thin, problems such as pinholes will occur.

On the other hand, it is believed that if a photosensitive thin film containing a photobleaching material is provided on the resist film, the resolution will be improved without adversely affecting the resist function. B.F.

Qriffing et al. proposed forming a photosensitive layer containing a photobleaching dye on a positive resist film.
E, ELECTRON DEVICE L, ETTER
8, V'ol, EDL-4, (1>14 (1983)
). In addition, a method has been proposed in which a photobleachable positive resist film is placed on a negative resist film to substantially improve the optical contrast (Japanese Patent Laid-Open No. 54-64985,
5.4-70761). By the way, the point of this method is to change the illumination distribution of the pattern by passing it through a photobleaching film, thereby apparently improving the optical foundation resistance of the resist. That is, the amount of color fading is small in shadow areas where the amount of light is relatively small, and the amount of color fading is large in highlight areas. Therefore, the transmitted light rays in the highlight areas are relatively stronger than those in the shadow areas, and the optical contrast with respect to the resist film is apparently improved. In order to effectively carry out this method of improving optical contrast, the fading substance must satisfy the following conditions. When dyes are used in fading materials, they must: ■ Sufficiently absorb the light that sensitizes the resist and fade; ■ The fading speed is close to the photosensitive speed of the resist; ■ After fading, the dye transforms into a sufficiently transparent material. , it is practically difficult to apply the dye due to the slow fading rate. When a positive resist itself is used as a fading material, it has a drawback that it has a small absorption coefficient and cannot sufficiently block light.

Increasing the thickness of the resist film improves the light-shielding ability, but the image becomes blurred and the resolution deteriorates.

[Object of the Invention] An object of the present invention is to provide a pattern forming method for solving the above-mentioned problems and stably obtaining a fine pattern with high dimensional accuracy using a simple method.

[Summary of the Invention] As a result of extensive studies, the present inventors have discovered that by providing a photobleachable thin film containing a photosensitive diazonium salt on a resist film, fine patterns can be stably obtained with good dimensional accuracy. This is the heading that led to the completion of the present invention.

The present invention is a pattern forming method characterized in that, after a photosensitive film is provided on a resist film, a pattern is exposed using a light beam that sensitizes both the resist and the photosensitive diazonium salt.

When a diazonium salt is used in the present invention, ultraviolet light (wavelength 300 to 450 nm)
Advantages such as (m) that the light-shielding ability can be sufficiently increased, (2) the photobleaching rate matches the photosensitivity of the resist, and (2) a completely transparent film can be obtained after photobleaching are obtained.

The fine pattern forming method of the present invention will be described in detail below.

First, a typical resist solution is applied onto a substrate such as a wafer and dried to form a resist film. Next, a diazo photosensitive solution is prepared by dissolving a photosensitive diazonium salt and a resin binder in a suitable solvent, and this photosensitive solution is applied to the resist film using a spinner or the like and dried to form a diazo photosensitive film. Next, pattern exposure is performed using a light beam that acts on both the resist and the diazonium salt. The diazo-sensitive layer is then removed and the resist layer is subsequently developed to obtain the pattern.

As the photosensitive diazonium salt used in the present invention, any conventionally known photosensitive diazonium salt can be used. Examples of this diazonium salt include ■J, Kosarll-ia
ht 3ensitive SystemsJ (19
65, J, WilV 5ons Inco, New
YOrk)paoe 194 ■M-3, [)inaburg[photosensi
tive Qiazo Compoundsand T
hair UsesJ (1964, The Focal
Press> ■R0patai rThe Chemistry of
[)iazonium and [)iaz.

Groups, Part I, ll-1 (19781,
1WileV) can be used.

In the pattern forming method of the present invention, diazonium salt compounds represented by the following general formulas (1), (2), and (2) are particularly preferred.

In the above general formula (1), R is alkyl, alkoxy, halogen atom, morpholino, pyrrolidinyl, or N.

Substituents such as N-dialkylamino,
3r tonohalogen atom, M is Fe, 3n.

Represents at least one selected from Sb, B, P, AS, Zn, AI, etc.

In the above general formula (1), R1 and R2 are alkyl or carbon,
R1 and R2 may be ring-closed via an oxygen or nitrogen atom, and Y and Z are hydrogen atoms, or substituents such as alkyl, allyl, aralkyl, alkoxy, alkylmercapto, aralkylmercapto, acyl, and halogen, represents a halogen ion or an anion composed of a halogen compound such as pho1j7, aluminum, iron, zinc, arsenic, antimony, or phosphorus.

Specific examples of diazonium salts represented by the general formula ■ are:
3.4-dimethyl-6-pyrrolidylbenzenediazonium salt, 3,4-dimethyl-6-morpholinobenzenediazonium salt, 4-benzoyl-2-(N,N-dimethylamino)benzenediazonium salt, 2- (N, N-phenylbenzenediazonium salt, 3-10mu-6,-(
N,N-dimethylamino)-5-methylthiobenzenediazonium salt, 4-acetylamino-2-(N,N-dimethyl7mino)diazonium salt, 4-■Toxy 2-(
N,N-dimethylamino)benzenediazonium salt, 3
-methoxy-4-benzoylamino-2-piperidinobenzenediazonium salt and the like can be mentioned.

In the above general formula (■), Y and Z are hydrogen atoms or alkyl,
Substituents such as allyl, aralkyl, alkoxy, alkylmercapto, aralgylmer, acyl, halogen atom, sulfone, carboxyl, etc., and X is a halogen ion or boron, aluminum, iron, zinc, arsenic, or Indicates an anion composed of halogen compounds such as phosphorus and phosphorus.

Specific examples of diazonium salts represented by the general formula ■ are:
4-α-naphthylaminohenzendi7zonium salt, 4-
β-nanothylaminobenzenediazonium salt, 4-6'
- Sodium sulfonate β-naphthylaminohempine silzonium salt, 4-5-monoacenaphtheminohenpine diazonium salt, 5-(4-aminobuenylamino>-i).

Examples include diazo compounds of 8-nano l-sartan.

Among the various diazonium salts, the reason why the diazonium salts represented by the above general formulas (1), (2), and (3) have particularly excellent effects is that the absorption band of the diazonium salts is strong in the visible light, especially in the 400 to 400 nm range.
This is because it can very effectively block the q-ray <43601'l of the mercury lamp, which is around 500 nm and is currently used for pattern exposure of integrated circuits. In other words, the diazonium salts that are generally applied in the field of copying, especially in photosensitive materials for microfiscico and diazo photosensitive paper for copying, have an absorption band at the longest wavelength, but the wavelength of the absorption peak is The limit is around 405 nm, and the Q-ray blocking ability is not sufficient. Furthermore, if a large amount of diazonium salt is dissolved in the resin binder, the light-shielding ability will be increased, but in reality, if the solubility limit is exceeded, the diazonium salt will crystallize, making it impossible to obtain a uniform transparent film.

- The diazonium salt according to Rikiki's invention does not have these problems because its absorption peak coincides exactly with the vicinity of the q-line.

Among the diazonium salts described above, zinc tetrachloride or boron tetrafluoride salts are suitable for use in the present invention. The solubility of diazonium salts in solvents varies depending on the type of these salts. For example, zinc tetrachloride salt is water soluble and 1. On the other hand, boron tetrafluoride salt is soluble in organic solvents. By the way, when a diazo photosensitive film is provided, it is not preferable to dissolve or partially dissolve the underlying resist film during coating to form a mixed layer consisting of the resist material and diazonium salt, since this lowers the resolution. For this reason, for a water-soluble resist, the diazo photosensitive solution should be composed of an organic solvent, a diazonium salt soluble therein, and a resin binder. For organic solvent-soluble resists, it is composed of water-soluble diazonium salts and water-soluble resins.

In the present invention, the diazonium salt 1 is added to the diazo photosensitive solution.
The compatibility of the diazonium salt with the resin binder can be improved by adding the benzenesulfonic acid derivative or its salt represented by the following general formula (L) at a ratio of 5 to 2 moles per mole. .

(However, X does not represent a hydrogen atom, an atom or an atomic group such as lithium, sodium, potassium, or ammonium, and Y and Z do not represent a hydrogen atom, a halogen atom, or a substituent such as a hydroxyl group, a carboxyl group, or an alkyl group.) By the way, in the above pattern forming process, even if the sulfone M derivative represented by the above general formula or its salt is not added to the diazo photosensitive liquid, the photobleaching rate that can sufficiently increase the ultraviolet ray blocking ability as described above may be used. The effect is that it matches the photosensitivity of the film, and that an almost completely transparent film can be obtained after photobleaching. However, when the sulfonic acid derivative represented by the above general formula or its salt is added to the diazo photosensitive solution according to the present invention, the solubility of the diazonium salt in the photosensitive state and the solubility in the photosensitive film state (compatibility with the resin binder) ) was found to improve dramatically.

Dissolution of diazonium salt in photosensitive film state w1. An increase in the strength means that a large amount of diazonium salt can be dissolved in the resin binder per unit weight, and as a result, the ultraviolet light blocking ability of the diazo photoresist film is dramatically improved. According to the present invention, in addition to the above-mentioned effects, the diazo photosensitive film can be made thinner, so image defocusing is reduced and resolution is improved, and the range of applicable diazonium salts is expanded. It was found that the effect of

The present inventors further investigated the compatibility of various diazonium salts and resin binders, and found that even in combinations with good compatibility, the amount of diazonium salt that can be dissolved in resin 1Q is approximately 2 mmoles, indicating that the compatibility is low. cannot be said to be large. In addition, many diazonium salts have absorption peak wavelengths around 370 to 405 nm, so
The G-line of the mercury lamp currently awarded for reduction projection exposure equipment (
436 nm), only the shoulder portion on the long wavelength side of the absorption band is effective, so the light blocking ability becomes smaller and smaller. Of course,
Although it is not impossible to apply special diazonium salts whose absorption peak is near the Q line, it is not always possible to satisfy additional conditions such as the stability of these diazonium salts against thermal decomposition and compatibility with resin binders. . Therefore, it would be highly advantageous to increase the solubility of diazonium salts in resin binders.

Under these circumstances, the present inventors conducted various inquiries regarding improving the solubility of diazonium salts in resin binders.
It has been discovered that when 0.5 to 2 moles of a benzenesulfonic acid derivative or its salt represented by the above general formula is added to a diazo photosensitive solution per mole of the diazonium salt, the solubility of the diazonium salt is surprisingly improved. When the benzenesulfonic acid derivative represented by the general formula or its salt is not used, as described above, the solubility of the diazonium salt in the resin binder 10 is at most about 2 mmol, but according to the present invention, it is 20 mmol, that is, Approximately 10 in case of addition
It was found that up to twice the solubility can be obtained.

The benzenesulfonic acid derivatives or salts thereof used in the present invention include benzenesulfonic acid, p-toluenesulfonic acid, p-ethylbenzenesulfonic acid, p-
Examples include benzenesulfonic acid derivatives such as hydroxybenzenesulfonic acid, cumenesulfonic acid, dodecylbenzenesulfonic acid, and sulfosalicylic acid, or salts thereof. The addition ratio of these compounds is preferably 0.5 to 2 mol, preferably 17 to 1.5 mol, of the above two compounds per 1 mol of the diazonium salt.

As the resin binder added to the diazo photosensitive solution of the present invention, both water-soluble resins and organic solvent-soluble resins can be used. Examples of water-soluble resin binders include polyvinylpyrrolidone, copolymers of vinyl methyl ether and maleic anhydride, polyvinyl alcohol, cellulose derivatives such as methyl cellulose, hydroxymethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose, gelatin, egg white, and casein. , natural resins such as shellac. Organic solvent-soluble resin binders include cellulose acetate butyrate resin, cellulose acetate, cellulose derivatives such as chilled cellulose, polyvinyl butyral, polyvinyl chloride, polyvinyl acetate, phenolic resin, polyester resin, methyl methacrylate and methacrylic acid. a copolymer of
Examples include acrylic resins such as copolymers of methyl acrylate and acrylic acid, but the present invention is not limited thereto.

In addition, diazo photosensitive liquids contain organic acids such as paratoluenesulfonic acid, sulfosalicylic acid, citric acid, tartaric acid, acetic acid, and nicotinic acid as thermal decomposition stabilizers for diazonium salts, and substances that improve the properties of the coating film. A surfactant, a foaming agent, etc. can also be used as appropriate.

To prepare a diazo photosensitive solution, the above-mentioned diazonium salt, resin binder, and additives are dissolved in a suitable solvent. Examples of organic solvents include alcohols, cellosolves, esters,
Ketones, THF, DMF, etc. are suitable. The blending ratio of the components constituting the diazo photosensitive liquid is preferably to increase the UV blocking ability, so the blending ratio of the diazonium salt to the resin binder is adjusted so that the diazonium salt crystallizes in the solution state and when forming the coating film. It is desirable to have a high M degree close to the critical concentration. In addition, when applying with a spinner etc., the viscosity of the photosensitive liquid is 5 to 1000 CPS, preferably 10
A range of ~200 CPS is desirable.

The film thickness of the diazo photosensitive liquid film is related to the light-shielding ability of the film and cannot be determined unconditionally, but it is 500A to 5μm, usually 10
00A to 2 μm is preferable. If it is less than 500 A, pinholes may occur, and if it is more than 5 μm, the image will be out of focus, which is not preferable.

After applying the diazo photosensitive solution, dry it. The drying conditions at this time must be determined mainly by taking into consideration the thermal stability of the underlying resist material and the diazonium salt. Diazonium salts usually begin to decompose at around 90°C, so 90°C
In the case of 1- below, it is necessary to shorten the drying time.

There is no particular restriction on the type of resist used in the lower layer of the present invention, but for example, a so-called positive resist consisting of a naphthoquinone diazide sulfonic acid ester and a cresol novolac resin, a bisazide compound blended with cyclized polyisoprene, etc. So-called rubber-based negative resist,
These include negative resists in which azide is dissolved in polyvinylphenol resin or phenol novolac resin, various resist materials in which dichromate is blended with water-soluble resin, and water-soluble resists in which azide compound is dissolved in polyvinylpyrrolidone. be able to.

In the present invention, the diazo photosensitive liquid may be applied directly to the resist layer formed on the substrate. Layers can also be formed.

When forming the intermediate layer made of the transparent thin film described above, the storage stability of the photosensitive liquid can be improved because an organic solvent-based diazo photosensitive liquid can be used.The thickness of the diazo photosensitive film can be easily controlled during the coating process. Effects such as easy removal of impurities from the liquid can be obtained.

Tokorore: As is well known, there are currently two types of resists used for semiconductor microfabrication: the photosensitive material naphthoquinone cyatosulfonic acid ester, and m-cresol novolak resin dissolved in cellosolve acetate. So-called positive resists and bisazide compounds,
A so-called negative resist in which cyclized rubber is dissolved in xylene or the like is used. Therefore, since the resist film formed with these resists is soluble in organic solvents,
Diazo photosensitive liquids made of organic solvents cannot be used because they dissolve the underlying resist film. On the other hand, it is possible to prepare an aqueous diazo photosensitive solution by appropriately selecting the anion of the diazonium salt. However, it has been found that water-soluble diazo photosensitive liquids have the following problems compared to organic solvent based photosensitive liquids.

The storage stability of photosensitive solutions is poor because diazonium salts are easily decomposed.

It is difficult to control the thickness of the diazo photoresist film during the coating process.

It is difficult to remove impurities from the photosensitive liquid.

The present inventors investigated various methods of applying an organic solvent-based diazo photosensitive liquid, and found that, without dissolving the resist film on the resist film, an M-soluble transparent thin film was provided on the diazo photosensitive liquid, and on top of the M-soluble transparent thin film was applied. It was confirmed that an organic solvent-based diazo photosensitive liquid can be used by applying a diazo photosensitive liquid, and that fine patterns can be obtained with almost no adverse effect on the fading effect of the diazonium salt even when such a transparent film is provided. child .

In order to provide the above-mentioned transparent thin film, ultraviolet rays (300 to 45
A conventional method is to spin-coat a polymer solution that is substantially transparent to 0 nm) onto the resist layer to form a transparent thin film. However, the polymer solution must not substantially dissolve the underlying resist film during spin coating, and the transparent thin film obtained after drying must not dissolve during the subsequent diazo photosensitive liquid coating process. conditions must be met. Polymers and solvent systems suitable for these conditions include polymer solutions in which rubber polymers such as cyclized polyisoprene, butadiene, and neorene are dissolved in xylene, toluene, and benzene, hydroxypropyl cellulose,
Aqueous solutions of water-soluble polymers such as methylcellulose, hydroxypropylmethylcellulose, polyvinyl alcohol, casein, gelatin, and shellac can be used.

The thickness of the transparent thin film obtained by spin-coating these polymer solutions is preferably as thin as possible, but usually 0.
03-3. czm, preferably 0.05 to 1 μm. If the film thickness is less than 0.03 μm, pinholes will occur and there is no point in forming a transparent thin film. Also 3 μm
The above is not preferable because it causes blurring of the image.

In order to form a pattern on a substrate on which a transparent thin film is formed, the diazo photoresist film and the transparent thin film are peeled off in this order after pattern exposure, and finally the resist film is developed. For peeling off diazo photosensitive films and transparent thin films, the solvents used in the respective coating solutions are usually used.

[Effects of the Invention] According to the present invention, a fine pattern of 1 μm or less can be formed stably with high dimensional accuracy by a simple method while utilizing conventional ultraviolet exposure techniques, which is an extremely excellent effect. , its industrial effects are great.

[Embodiments of the invention] Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1, Comparative Example 1 Positive resist (Tokyo Ohka Kogyo) on silicon wafer
Co., Ltd., product name 0FPR-800, 1゜2-naphthoquinonediazide-(2)-5 sulfonic acid ester.
−1 dissolved in Talesol novolac resin
It was provided with a film thickness of μm.

Next, a diazo photosensitive solution having the following composition was prepared, spin-coated onto the positive resist, and dried at 80° C. for 10 minutes to form a 0.4 μm diazo photosensitive film.

2.5-Jethoxy-4-morpholinobenzenediazonium chloride 1/2 zinc chloride double salt (MW382) 2
0 mmol polyvinylpyrrolidone (manufactured by GAF, 90 in the trade name)
IO Durham pure water 200ml Next, the effects of the sample according to the present invention obtained in this manner and a sample consisting only of a positive resist film were compared using the following method.

Using a reduction projection exposure device equipped with a 10:1 reduction projection lens with a numerical aperture of 0.35, we measured the dimensions of the resist pattern after development when a 1 μm pattern was exposed for different exposure seconds. is shown in Figure 1. In the conventional method without a diazo photoresist, the exposure time to obtain a line width of 1 μm is approximately 0.
4 seconds, but it has been shown that using the structure of the present invention increases the time to 2 seconds. However, when we investigated the exposure time dependence of the line width after development, we found that the slope of the straight line in the structure of the present invention was about 1/3 that of the conventional method, and the controllability of dimensions was greatly improved. I can see that it is being done.

Furthermore, the results of comparing the dimensional accuracy are shown in FIG.

The normally required dimensional accuracy is said to be within 10% of the 3σ dimension, and the minimum line width that satisfies this is approximately 1.2 μm in the conventional method, whereas in the method of the present invention is approximately 0.9 μm, which indicates a significant improvement.

Example 2 Instead of the diazonium salt used in Example 1, 2.5-
The same experiment as in Example 1 was carried out except for using jetoxy-4-p-methoxyphenylthiobenzenediazonium chloride 1/2 zinc chloride double salt, and the same as in Example 0.9
A μm pattern was obtained.

Example 3 An experiment similar to Example 1 was conducted except that a photosensitive solution having the composition shown below was used instead of the diazo photosensitive solution used in Example 1. As a result, a clear pattern of 0.9 μm was obtained.

2.5-Jethoxy-4-I)-methoxybenzoylaminobenzenediazonium chloride 1/2 zinc double salt
20 mmol vinyl methyl ether and maleic anhydride copolymer (G
AF company, product name GANTREZ A N-139> 1
0 'j RaL pure water 200ml Example 4 The same experiment as in Example 3 was conducted except that 3-methoxyl-4-pyridinylbenzenechloramo was used as the diazonium salt in the diazo photosensitive liquid used in Example 3. Result: 0.
A clear pattern of 8-0.9 μm was obtained.

Comparative example 2 The following mixture was prepared as a solution containing the fading dye.

Rhodamine 6G 10 mmol polyvinylpyrrolidone (manufactured by GΔF, product name -90>
10 g water 200 ml This dye solution was applied onto the positive resist film used in Example 1 to provide a dye film with a dry film thickness of 0.7 μm. As a result of evaluating the pattern by changing the exposure time in the same manner as in Example 1,
It took more than 16 minutes to obtain a 1 μm pattern.
It turned out to be impractical.

Comparative Example 3 A normal negative resist (manufactured by Tokyo Ohka Co., Ltd., trade name OMR-83, 2°6-bis(4-acidobenzal)cyclohexanone derivative dissolved in cyclized polyimbrene) was applied on a silicon wafer. The film thickness was 1.0 μm. Next, the positive resist used in Example 1 was applied onto this resist film to a thickness of 0.5 μm. Exposure was performed using a projection type exposure device equipped with a 1:1 mirror (manufactured by Canon Inc., trade name PLA-520). Exposure was performed while changing the exposure time, and after exposure, the positive resist was removed with cellosolve acetate. Next, we evaluated the pattern obtained by developing with a xylene-based developer.As a result, it was found that the pattern was 2.0μ with or without a positive resist film.
It was found that a fine pattern smaller than m could not be obtained.

Example 5, Comparative Example 4 Positive resist (Tokyo Ohka Kogyo (Tokyo Ohka Kogyo))
Co., Ltd., product name 0FPR-800> was provided to a thickness of lum.

Next, a diazo photosensitive solution having the following composition was prepared and spin-coated onto the above positive resist at 80°C.

It was dried for 10 minutes to form a 0.4 μm diazo photosensitive film. The effects of the obtained sample of the present invention and a comparative sample in which no diazo photosensitive film was formed were measured by the method described in Example 1. FIG. 3 shows the results of measuring the dimensions of the resist pattern after development. In the conventional method without a diazo photosensitive film, the exposure time to obtain a line width of 1 μm is approximately 0.4 seconds, but in the method of the present invention, the exposure time is increased to 4 seconds. However, when examining the exposure time dependence of the line width after development, it was found that in the present invention, the slope of the straight line is about 1/3 to 1/3 compared to the conventional method.
It becomes 1/4, and it can be seen that the dimensional accuracy of the present invention is greatly improved.

In addition, the results of comparing the dimensional accuracy are shown in Figure 4.The minimum line width of the present invention is approximately 0.7 μm, whereas that of the conventional method is 1 μm.
．． 2 μm, 1, which is a significant improvement.

Example 6 Instead of the diazonium salt used in Example 5, 3.4-
Dimethyl-6-morpholinobenzenediazonium chloride 1/2 zinc chloride double salt (absorption peak wavelength: 445 nm
Example 5 The same experiment as Example 5 was conducted except that > was used.
Similarly, a 0.7 μm pattern was obtained.

Example 7 An experiment similar to Example 5 was conducted except that a photosensitive solution having the composition shown below was used instead of the diazo photosensitive solution used in Example 5. As a result, a clear pattern of 0.8 μm was obtained.

2-(N,N-dimethylamino)-5-methyldiobenzenediazonium chloride 1/2 zinc chloride double salt (absorption peak wavelength = 450 mn) 20 mm-E/Lz Copolymer of vinyl mer ether and maleic anhydride <GA
Company F's product name GANTREZAN-13] 10 grams Pure water 200ml Example 8, Comparative Example 5 Example 1 except that the following composition was used as the diazo photosensitive liquid
A pattern was formed in the same manner. As a result, the exposure time to obtain a line width of 1 μm was 3 seconds. In addition, as a result of measuring the exposure time dependence of line width and dimensional accuracy, Example 5
The same results were obtained.

4-α-Naphthylaminobenzenediazonium chloride 1/2 zinc chloride double salt (absorption peak wavelength: 435 nm) 20 mmol polyvinylpyrrolidone (manufactured by GAF, trade name: -90) 10 grams Pure water 200 ml Example 9 Examples 4-β instead of the diazonium salt used in 8.
-Naphthylaminobenzenediazonium chloride 1/
The same experiment as in Example 8 was conducted except that zinc dichloride double salt (absorption peak wavelength: 470 nm) was used, and a pattern of 0.8 μm was obtained as in Example 8.

Example 1゜An experiment similar to Example 8 was conducted using a photosensitive solution having the following composition instead of the diazo photosensitive solution used in Example 8. The result was 0.
．． A clear pattern of 8 μm was obtained.

4.6=--Sodium sulfonate β-naphthylaminobenzenediazonium chloride 1/2 zinc chloride double salt (absorption peak wavelength: 465 nm > 20 mmol Copolymer of vinyl methyl ether and maleic anhydride (G
AF company product name GANT'RE7Al'l-139> 1
0g pure water 200ml Example 11 A positive resist (manufactured by Tokyo Ohka Co., Ltd., trade name 0FPR-800) was formed to a thickness of 1 μm (7) on a silicon wafer.

Next, using a 5% xylene solution of cyclized polyisoprene,
A transparent film with a film thickness (11 μm) was formed on the above resist film by a spin coating method.Next, a diazo photosensitive solution having the following composition was prepared, and the resulting photosensitive solution was coated on the transparent thin film by a spin coating method to form a C film. A diazo photoresist film with a thickness of 0.4 μm was prepared.The method described in Example 1 was followed for the sample thus obtained.
As a result of forming a pattern, the initial exposure time to obtain a pattern with a line width of 1 μrp was 2 seconds. Also, dimensional accuracy 3
σ.

The minimum line width that satisfies the condition of within 10% is approximately 0.9 μm, compared to 1.2 μm in the conventional method using only positive resist.
It was much better compared to.

Example 12 Instead of the diazonium salt used in Example 11, 2.5
A pattern was formed in the same manner as in Example 11 using -jethoxybenzene siazonium tetrafluoroborate (absorption peak wavelength: 40/lnm).
A 9 μm pattern was obtained.

Example 13 A pattern was formed in the same manner as in Example 11 using a photosensitive liquid having the following composition as a diazo photosensitive liquid. As a result, CL
A clear pattern of 8 μm could be obtained.

3-Methoxy-4-pyrrolidinylbenzenediazonium tetrafluoroborate (absorption peak wavelength: 411 nm)
20 mmol polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd., trade name: Sletsk BMS) 10 grams Solvent (cellosolve acetate/Atriton mixture volume ratio 8:2>
200m1 Example 14 As a result of an experiment similar to Example 11 using a 10% aqueous solution of hydroxypropyl cellulose as a polymer solution for forming a transparent thin film, a clear pattern with a minimum line width of 0°9 μm was obtained. .

Example 15 Positive resist (manufactured by Tokyo Ohka Co., Ltd., trade name OF'P)
A transparent thin film with a thickness of 0.1 μm was provided on a resist film of a silicon wafer formed with R-800> with a thickness of 1 μm using a 5% xylene solution of cyclized polyisoprene.

Next, a diazo photosensitive solution having the following composition was prepared, and this was applied onto the transparent thin film by spin coating to a film thickness of 0. /Iμm diazo photoresist film was used. When a pattern was formed according to Example 1, the exposure time to obtain a pattern with a line width of 1 μm was about 4 seconds. Also, the minimum line width that satisfies the dimensional accuracy of 3σ and within 10% was approximately 0.7 μm.

Example 16 2,5-simi-1-toxybenzenediazonium borate tetrafluoride as a diazonium salt (absorption peak wavelength: 4
Pattern formation was performed in the same manner as in Example 15 using 0.04 nm), and as a result, a 0.7 μm pattern was obtained.

Example 17 A pattern was formed in the same manner as in Example 15 using a diazo photosensitive liquid having the following composition. As a result, a clear pattern of 0.7 μm was obtained.

3-Methoxy-4-pyrrolidylbenzenediazonium tetrafluoroborate (absorption peak wavelength: 411 mnm)
200 mmol p-hydroxybenzenesulfonic acid 230 mmol polyvinyl butyral resin (Sekisui Chemical Co., Ltd., trade name Sletsku BMS) 10 grams Solvent (cellosolve acetate/acetone mixture volume ratio 8:2 > 200 m1 Example 18 High As a result of conducting the same experiment as in Example 15 using a 10% aqueous solution of hydroxypropyl cellulose as the molecular solution, a clear pattern with a minimum line width of 0.7 μm was obtained.

Example 19 A diazo photosensitive solution having the following composition was applied onto the positive resist of Example 15 to provide a diazo photosensitive film having a thickness of 0.4 μm.

2.5-Jethoxy-4-morpholinobenzenediazonium chloride 1/2 Zinc chloride 200 mmol p-toluenesulfonic acid 230 mmol Polyvinylpyrrolidone (manufactured by GAF, trade name ~90>
, 10 g pure water 200 ml Thereafter, pattern formation was carried out in the same manner as in Example 15. As a result, it was found that a clear pattern of (17 μm) was obtained.

[Brief explanation of the drawing]

1 to 4 are graphs for explaining the present invention in detail, and FIGS. 1 and 3 are graphs showing the dependence of line width on exposure time after pattern development, FIGS. 2 and 4 are diagrams showing the line width dependence of variations in dimensional accuracy. Representative Patent Attorney Kensuke Norichika (and 1 other person) Figure 1 Paste Meat V) Figure 2 θ 7 2 3 tI Line Convergence (mm) 3rd Figure f 02 θ4 lL6 Q? fl 2. b ta
, p 1. tr R1fbfi Genchu & wo Mukaikuy) Figure 4 ρ f 2 3 4 Ito Kofuku (7rL)

Claims (1)

[Scope of Claims] (1) A photosensitive film containing a photosensitive diazonium salt is provided on a resist film, and then a pattern is exposed using a light beam that sensitizes both the resist and the photosensitive diazonium salt. Pattern forming method (2) Claim 1, characterized in that the photosensitive diazonium salt is a compound represented by the following general formula:
The pattern forming method described in Section 2 (where R1 and R2 are an alkyl group, or R1 and R2 are formed via a carbon, oxygen, or nitrogen atom)
may be ring-closed, Y and 7 are hydrogen atoms, or substituents such as alkyl, allyl, aralkyl, alkoxy, 7-furkylmercapto, aralkylmercapto, acyl, and halogen, and X is a halogen ion or (3) The photosensitive diazololam salt is a compound represented by the following general formula. Claim 1
The pattern forming method described in section (However, Y and Z are hydrogen atoms,
or a substituent such as alkyl, allyl, aralkyl, alkoxy, alkylmercapto, aralkylmercapto, acyl, halogen atom, sulfone, carboxyl, etc., where X is a halogen ion, or boron, aluminum,
Indicates an anion composed of halogen compounds such as iron, zinc, arsenic, antimony, and phosphorus) (4) Diazonium photosensitive liquid or benzenesulfonic acid derivative or its salt represented by the following general formula per 1 mole of diazonium salt. 0
．． The pattern forming method according to claim 1, characterized in that the compound is added in a proportion of 5 to 2.0 moles (wherein, The atomic group, Y, and Z represent substituents such as hydrogen atoms, halogen atoms, hydroxyl groups, small xyl groups, and alkyl groups) (5) <I> Apply a resist solution onto the substrate and dry it to form a resist film. (II) forming a transparent thin film on the resist film that is sparingly soluble in a photosensitive solution containing the following diazonium salt without dissolving the resist film; (III) forming a diazonium salt on the transparent thin film; (IV) forming a diazo photoresist film by applying a photosensitive solution containing the diazonium salt; A pattern forming method (6) according to claim 1.A pattern forming method according to claim 1, wherein the light beam is a visible light beam having a wavelength of 4oor-1n or less.