JPH05114559A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To pattern a light transmissive film without deteriorating the accuracy and reliability of the pattern by setting the film thickness and extinction coefficient of a carbon film and wavelength of exposing light in a specific relation. CONSTITUTION:After a carbon film 5 and photosensitive resin layer 6 are successively formed on a light transmissive film 4 to be worked, a desired pattern is formed by exposing and developing the layer 6. Then the film 5 is etched by using the formed pattern as a mask and the film 4 is etched by using the layer 6 or film 5 as another mask. At the time of etching the film 4, the film thickness (d) and extinction coefficient (k) of the carbon film 5 and the wavelength lambda of the exposing light are set so that they can satisfy a specific relation, 0.17<=kd/lambda. As a result, the exposing light is sufficiently weakened after passing through the layer 6. Therefore, the intensity of the light reflected by a light reflecting film 3 below the film 4 can be lowered to a sufficiently low level and abnormal exposure of the photosensitive resin layer 6 by the reflected light can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to improvement of pattern processing of an insulating film or the like.

[0002]

2. Description of the Related Art Conventionally, in the manufacturing process of semiconductor devices,
The patterning of the interlayer insulating film is performed as follows.
20 and 21 are process sectional views showing the method. First, as shown in FIG. 20A, the insulating film 52 is deposited on the semiconductor substrate 51, and then the lower layer wiring 5 is formed on the insulating film 52.
3 is formed.

Next, as shown in FIG. 20 (b), an insulating film 54 to be an interlayer insulating film is deposited on the entire surface, and then FIG. 20 (c).
As shown in, a photoresist (photosensitive resin layer) 55 is directly applied on the insulating film 54.

Next, as shown in FIG. 20 (d), a desired pattern is exposed on the photoresist 55, and then the photoresist 55 is exposed as shown in FIG.
As shown in (a), the photoresist 55 is developed to form a photoresist pattern 55.

Next, as shown in FIG. 21B, the insulating film 54 is selectively etched by the reactive ion etching (RIE) method using the photoresist pattern 55 as a mask. Finally, as shown in FIG. 21C, the photoresist pattern 55 is removed, and the pattern of the interlayer insulating film 54 is removed.
Is completed. However, this method has the following problems.

As shown in FIG. 20D, a part of the incident light 56 that has passed through the photoresist 55 during exposure further passes through the insulating film 54 and reaches the surface of the lower layer wiring 53. Is reflected as reflected light 57 and enters the photoresist 55 again. In addition, another incident light 56a is the insulating film 5
After passing through 4, 52, it reaches the semiconductor substrate 51, is reflected as reflected light 58 on this surface, and enters the photoresist 55 again. The photoresist 55 is exposed again by these reflected lights 57 and 58. At this time, since the optical properties of the lower layer wiring 53 and that of the semiconductor substrate 51 are different, the intensity of the reflected light 57 and that of the reflected light 58 are different.
Further, the distance of the insulating film through which the reflected light 57 passes and the reflected light 58
Therefore, a phase difference occurs when reaching the photoresist 55, and a difference in light intensity occurs when the light interferes with the incident lights 56 and 56a.

Therefore, the photosensitivity of the photoresist 55 varies greatly depending on the position, which causes a problem that the mask pattern cannot be faithfully transferred to the photoresist 55. 22 and 23 show other conventional insulating film patterns.
FIG. 6 is a sectional view of a forming process showing a method of polishing.

First, as shown in FIG. 22A, the surface of a semiconductor substrate 61 is selectively oxidized to form an oxide insulating film 62, and subsequently, the substrate 61 on which the oxide insulating film 62 is formed is formed.
An insulating film 63 and a polysilicon film 64 are formed in this order on the entire surface of.

Next, as shown in FIG. 22B, an insulating film 65 is deposited on the polysilicon film 64, and then a photoresist 66 is directly coated on the insulating film 65 as shown in FIG. 22C. ..

Next, as shown in FIG. 22 (d), after exposing the photoresist 66 to a desired pattern, FIG.
As shown in FIG. 3, a developing process of the photoresist 66 is performed to form a photoresist pattern 66.

Next, as shown in FIG. 23B, the insulating film 65 is selectively etched by the reactive ion etching (RIE) method using the photoresist pattern 66 as a mask. Finally, as shown in FIG. 23 (c), the photoresist pattern 66 is removed to complete the patterning of the insulating film 65. However, this method also has the following problems.

That is, as shown in FIG. 22D, the incident light 67 that has passed through the photoresist 66 during exposure further passes through the insulating film 65 and reaches the surface of the polysilicon film 64. Since the light penetrates into the photoresist 66 again after being reflected as reflected light 68, the photoresist 66 is exposed to a portion other than the portion determined by the mask pattern, resulting in abnormal exposure. In particular, as shown in FIG. 22D, when the surface roughness of the polysilicon film 64 is large, the effect of abnormal exposure is large, and as a result, as shown in FIG. The pattern to be transferred to is distorted as compared with the mask pattern.

Further, when the film thickness of the insulating film 65 varies depending on the position, the phase of the reflected light 68 reaching the photoresist 66 differs depending on the arrival position, and therefore the intensity of the light when interfering with the incident light 67. And the size of the photoresist pattern 66 varies depending on the position.

The dimensional difference due to the distortion and the position of the photoresist pattern 66 is caused by the photoresist pattern 66.
After the insulating film 65 is subjected to RIE using the mask as a mask, the pattern is reflected in the insulating film 65, so that the pattern of the insulating film 65 also has a dimensional difference due to distortion and position. Such inconvenience
This not only lowers the accuracy and reliability of the patterning of the insulating film, but also reduces the product yield.

In order to avoid this kind of problem, a method of patterning an insulating film using a dye-containing resist has been proposed. However, the method using the dye-containing resist is insufficient to suppress the distortion of the photoresist pattern due to abnormal exposure, cannot solve the above-mentioned problems, and further, the focus at the time of exposure. However, there was a problem that the margin of the

[0016]

As described above, in the conventional insulating film patterning process, when the photoresist is exposed, the exposure light is reflected on the surface of the semiconductor substrate or the lower metal wiring. Therefore, the pattern transferred to the photoresist is distorted. As a result, the insulating film is patterned using the distorted photoresist pattern as a mask.
Therefore, there is a problem that the precision and reliability of the patterning are lowered and the manufacturing yield is lowered.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a light-transmitting film formed on a light-reflecting film without degrading accuracy and reliability. It is an object of the present invention to provide a method of manufacturing a semiconductor device capable of patterning a processed film.

[0018]

In order to achieve the above object, the present invention provides a method of manufacturing a semiconductor device including a step of patterning a translucent film to be processed on a light reflective film. After a carbon film and a photosensitive resin layer are sequentially formed on a translucent film to be processed, a desired pattern is formed by an exposure process and a development process.
Patterning the photosensitive resin layer into a pattern, etching the carbon film using this as a mask, etching the film to be processed using the photosensitive resin layer or the carbon film as a mask,
The relationship between the film thickness d of the carbon film, the extinction coefficient k of the carbon film, and the wavelength λ of the exposure light is set to 0.17 ≦ kd / λ.

[0019]

According to the research conducted by the present inventors, the exposure light that has passed through the photosensitive resin layer has a relationship that the relationship between the film thickness d of the carbon film, the extinction coefficient k, and the wavelength λ of the exposure light is 0. It was found that when 17 ≦ kd / λ was satisfied, the carbon film was sufficiently weakened. As a result, the intensity of the light reflected by the light-reflecting film below the translucent film to be processed becomes sufficiently small, and there is no problem that the photosensitive resin layer is abnormally exposed by the reflected light.

Therefore, if a carbon film is provided between the light-transmitting processed film and the photosensitive resin layer and the photosensitive resin layer is exposed and developed, an accurate resist pattern can be easily formed. The accuracy and reliability of patterning are improved.

[0021]

Embodiments will be described below with reference to the drawings. 1 and 2 are sectional views showing a process of forming a connection hole according to the first embodiment of the present invention.

First, as shown in FIG. 1A, a SiO ₂ film 2 having a thickness of 1 μm is formed on a Si substrate 1 on the surface of which elements (not shown) are formed. Next, an Al wiring (light reflecting film) 3 having a thickness of 800 nm is formed on the SiO ₂ film 2.

Next, as shown in FIG. 1B, a 1 μm thick SiO ₂ film 4 is formed as an interlayer insulating film on the entire surface. Here, a step was formed on the surface of the SiO ₂ film 4 corresponding to the Al wiring 3.

Next, as shown in FIG. 1C, a carbon film 5 having a thickness of 80 nm is formed on the SiO ₂ film (processed film) 4. This carbon film 5 can be formed by a DC magnetron sputtering method using a graphite plate as a target in an Ar atmosphere. The formation conditions are room temperature and a pressure of 4 × 10.
^-3 Torr, power density 3.5W / cm ² , Ar flow rate 40
It is SCCM. When the structure of the carbon film 5 was examined by X-ray diffraction, it was found that the structure was an amorphous structure or a microcrystal structure. When the optical constants were measured using an optical Ellipson meter, the refractive index n was 1.86 and the extinction coefficient k was 0.79 when the exposure wavelength was 365 nm. Furthermore, when the specific resistance was measured by the four-point probe method, it was found that
A value of 3 Ωcm was obtained.

Next, as shown in FIG. 1D, a positive photoresist (photosensitive resin layer, PFI15AA manufactured by Sumitomo Chemical Co., Ltd.) 6 having a thickness of 1.5 μm is applied on the carbon film 5 to form a mask pattern ( This photoresist 6 is exposed using (not shown). Mask pattern is 0.5μm and 0.7μm
The contact hole pattern of □ was used. The exposure wavelength is 365 nm.

Next, as shown in FIG. 2A, the photoresist 6 is developed by using a developing solution, for example, an alkaline developing solution containing choline as a main component, to form a photoresist pattern 6. When the photoresist pattern 6 was examined, it was found to be faithful to the mask pattern with almost no influence of reflection from the Al wiring 3 or the substrate 1 during exposure, as will be described later. In addition, when the carbon film 5 was examined, elution and peeling were not observed at all.

Next, as shown in FIG. 2B, RI using O ₂ gas is used with the photoresist pattern 6 as a mask.
The carbon film 5 is patterned by the E method, and then CF
_The SiO ₂ film 4 is patterned by the RIE method using ₄ gases. Finally, as shown in FIG. 2C, an ashing process using oxygen plasma is performed to perform photoresist patterning.
The carbon film 6 and the carbon film 5 are peeled off at the same time.

In this embodiment, 0.5 μm □ and 0.7 μm
A mask pattern of m.quadrature. contact hole pattern was used, and the dimensions of the pattern transferred to the photoresist 24 were 0.48 .mu.m.quadrature. and 0.70 .mu.m.quadrature., respectively. Further, the in-plane variation in the 6-inch wafer having the contact hole size of 0.70 μm was ± 1.8%.

For comparison, when the insulating film was patterned without providing a carbon film between the photoresist and the SiO ₂ film, the pattern resolution of 0.50 μm □ could not be obtained. The in-plane variation on a 6-inch wafer with a contact hole size of 0.70 μm is ± 8.8.
It was a very large percentage. The reason why the mask pattern can be faithfully transferred to the photoresist 6 by the method of this embodiment is considered as follows.

That is, after passing through the photoresist 6, the substrate 1
This is because the light reflected by the Al wiring 3 and the Al wiring 3 is sufficiently weakened in the carbon film 5, and as a result, the intensity of the reflected light becomes sufficiently small, and the abnormal exposure due to the reflected light hardly occurs. Further, since the reflectance of the carbon film 5 is small, the problem that the photoresist 6 is abnormally exposed to the light reflected by the surface of the carbon film 5 hardly occurs. Moreover,
Since the intensity of the reflected light is weak as described above, even if the thickness of the insulating film changes depending on the location and the phase of the reflected light shifts, the problem of changing the dimension of the resist pattern does not occur.

Thus, according to the present embodiment, the distortion of the pattern transferred to the photoresist 6 is reduced, the resolution is improved, and stable and uniform accurate photo is obtained regardless of the thickness of the SiO ₂ film 2. A resist pattern can be formed, so that the patterning of the SiO ₂ film 4 can be made highly accurate and highly reliable. 3 and 4 are sectional views showing the steps of forming an insulating film pattern according to the second embodiment of the present invention.

First, as shown in FIG. 3A, the Si substrate 1
No. 1 surface is selectively oxidized to form a 1 μm thick SiO ₂ film 1
Form 2. Then, on the substrate 11 on which the SiO ₂ film 12 is formed, a SiO ₂ film 13 having a thickness of 800 nm and a thickness of 1 are formed.
A μm polysilicon film (light-reflecting film) 14 is sequentially formed. Here, a step corresponding to the SiO ₂ film 12 was formed on the surface of the polysilicon film 14. Next, as shown in FIG. 3B, a Si film having a thickness of about 300 nm is formed on the polysilicon film 14.
An O ₂ film 15 (working film) is deposited. Next, as shown in FIG. 3C, a carbon film 1 having a thickness of 80 nm is formed on the SiO ₂ film 15.
6 is deposited.

Next, as shown in FIG. 4A, a positive photoresist (photosensitive resin layer, PFI15AA manufactured by Sumitomo Chemical Co., Ltd.) 17 having a thickness of 1.5 μm is applied on the carbon film 16 to form a wiring mask pattern. This photoresist 17 is exposed using a photoresist (not shown). At this time, the exposure wavelength is 365 nm.

Next, as shown in FIG. 4B, the photoresist 17 is developed with a developing solution to have a pattern width of 0.8 .mu.m.
m photoresist pattern 17 is formed. As will be described later, when the photoresist pattern 17 was examined, it was found that the light reflected by the polysilicon film 14 at the time of exposure had almost no effect and was faithful to the mask pattern.

Finally, the carbon film 16 and the SiO ₂ film 15 are sequentially etched using the photoresist pattern 17 as a mask, and then the carbon film 16 and the photoresist pattern 17 are formed.
Is removed by ashing.

5 (a) and 5 (b) respectively show a top view of the photoresist pattern formed by the method of this embodiment and that when the conventional method is used. In the figure, the shaded area represents the photoresist pattern.

As shown in FIG. 5 (a), in the method of this embodiment, no broken portion is observed in the photoresist pattern 17, and it is understood that the mask pattern can be faithfully transferred to the photoresist 17.

On the other hand, when the photoresist 17a is patterned by the conventional method as shown in FIG. 5 (b), the photoresist pattern 17a has a large number of steps, especially at a step. The disconnection portion 18 was observed.
This is because the exposure light is reflected on the surface of the polysilicon film 14 in the conventional method, so that the distorted pattern is transferred to the photoresist 17a. In the figure, 15a is an interlayer insulating film. The reason why the mask pattern can be faithfully transferred to the photoresist 17 in this manner is considered as follows.

That is, since the light passing through the photoresist 17 and reflected by the polysilicon 14 is sufficiently weakened in the carbon film 16, the intensity of the reflected light by the polysilicon 14 becomes sufficiently small, and the photo by the reflected light is reduced. Resist 17
Abnormal exposure hardly occurs. Further, even if the thickness of the insulating film changes depending on the location and the phase of the reflected light is shifted, the problem of changing the dimension of the resist pattern does not occur.

Thus, according to this embodiment, the SiO ₂ film 1
By providing the carbon film 16 between the photoresist 5 and the photoresist 17, the distortion of the mask pattern transferred to the photoresist 17 is reduced, the resolution is improved, and the film thickness of the underlying SiO ₂ film 15 and Even if the film thickness of the carbon film 16 is not uniform, a stable photoresist pattern with good uniformity can be formed. Therefore, the patterning of the photoresist 17 can be made highly accurate and highly reliable, and the S
It enables highly accurate processing of the iO ₂ film and the polysilicon film, and improves the manufacturing yield.

By the way, in the above-mentioned two embodiments, the case where the thickness of the carbon film is 80 nm has been described. However, the present inventors have found that the intensity of the reflected light is sufficient if the thickness of the carbon film is 80 nm or more. I confirmed that it can be made smaller.

6 to 17 are diagrams showing this.
6 and 7 show that the carbon film thickness d _C is 0 nm (no carbon film)
(In the resist, the percentage of the intensity of the reflected light to the intensity of incident light) the film thickness and the reflectance of the SiO ₂ film in the case of a characteristic diagram showing the relationship between the respective polysilicon film, a SiO ₂ film on the Al film It is when formed. Similarly, FIGS. 8 and 9 are characteristic diagrams showing the relationship between the thickness of the SiO ₂ film and the reflectance when the thickness of the carbon film is 20 nm, and FIGS.
Is a characteristic diagram showing the relationship between the SiO ₂ film thickness and the reflectance when the carbon film thickness is 40 nm, and FIGS. 12 and 13 are SiO ₂ film thickness when the carbon film thickness is 60 nm. And FIG. 15 are characteristic diagrams showing the relation between the reflectance and the reflectance. FIGS. 14 and 15 are characteristic diagrams showing the relation between the thickness of the SiO ₂ film and the reflectance when the thickness of the carbon film is 80 nm. Carbon film thickness is 100n
FIG. 7 is a characteristic diagram showing the relationship between the film thickness of the SiO ₂ film and the reflectance in the case of m.

The reflectance γ is the wavelength λ of the exposure light λ = 36.
The thickness is 5 nm and the optical constants shown in Table 1 below are used. The optical constants shown in Table 1 are those obtained by measurement with a spectroscopic Ellipson meter.

[0044]

[Table 1]

[0045]

[Equation 1]

Here, d _B is the film thickness of the SiO ₂ film, d _c is the film thickness of the carbon film, λ is the wavelength of the exposure light, and N _A is the optical constant of the light-reflecting film (polysilicon film, Al film). , N _c is the optical constant of the carbon film, N _B is the optical constant of the SiO ₂ film, N _R is the optical constant of the photoresist, and r _R = (N _R −N _c ) / (N _R +
N _c ), r _c = (N _c −N _B ) / (N _c + N _B ), r _B =
(N _B -N _A) a _{/ (N B + N A)} . However, the optical constant N is N = n-ik (n: refractive index, k: extinction coefficient)
It is represented by.

From these figures, the underlying polysilicon film,
It can be seen that the reflectance is 10% or less when the thickness d _{c of the} carbon film is 80 nm or more regardless of the thickness d _B of the Al film or the SiO ₂ film.

From these figures, the reflectance is SiO ₂
It can be seen that the film thickness d _B changes periodically. This is because the reflected light on the surface of the polysilicon film or the Al film interferes with the incident light, the interference between the reflected light on the surface of the SiO ₂ film and the incident light, or the reflected light on the surface of the carbon film. The cause is interference with reflected light on the surface of the polysilicon film or the surface of the Al film. In addition, the period is the wavelength of the incident light is SiO
It is one half of the value divided by the refractive index of the _two films, which is about 120 nm. It can be seen that such a periodic change in reflectance is also extremely small when the thickness d _{c of the} carbon film is 80 nm or more.

The present inventors also examined the film thickness dependence of the light absorption of the carbon film. FIG. 18 shows the result, and is a characteristic diagram showing the relationship between the light absorptance I / I ₀ and the thickness of the carbon film. Here, I is the transmitted light intensity and I ₀ is the incident light intensity. The light absorptance I / I ₀ is I / I ₀ = exp (−4πkd / λ) where d is the thickness of the carbon film, k is the extinction coefficient of the carbon film, and λ is the wavelength of light. FIG. 18 corresponds to the case where k = 0.79 and λ = 365 nm.

FIG. 18 shows the dependence of the light absorption rate I / I _{0 on} the thickness of the carbon film. From the above equation, the light absorption rate I / I ₀ is
It can be seen that it also depends on the extinction coefficient k and the wavelength λ. Therefore, regarding FIGS. 6 to 17, the thickness of the carbon film is 80 nm.
Although it has been described that the reflectance is 10% or less in the above cases, the reflectance can be 10% or less even when the thickness of the carbon film is less than 80 nm.

That is, d = 80, k = 0.79, λ = 36
Substituting 5 for kd / λ in the above equation yields a value of 0.173.
Therefore, if the relationship of kd / λ ≧ 0.173 is satisfied,
An underlying light-reflective film such as a polysilicon film or an Al film, or Si
Even if the optical constants of the translucent film such as the O ₂ film or the carbon film and the wavelength of the exposure light are changed, the intensity of the reflected light from the light reflective film can be suppressed to the same level. Therefore, good patterning can be performed as in the above embodiment. Conversely, λ is 200 nm
In the above, when k is substantially 0, that is, the diamond film cannot be used even if it is a carbon film because it does not satisfy the above relationship.

In the above embodiments, the case where the light reflecting film is a polysilicon film or an Al film has been described, but other metal films, alloy films, silicide films, semiconductor films or the like may be used. In addition, as a translucent film to be processed, SiO _{2 is used.}
Although the insulating film has been described, it may be a translucent insulating film made of other oxide or nitride. FIG. 19 is a sectional view showing the steps of forming an insulating film pattern according to the third embodiment of the present invention.

First, as shown in FIG. 19A, a SiO ₂ film (workpiece) is formed on a Si substrate 21 (light-reflecting film) on which a desired element (not shown) is formed by using a plasma CVD method. The film 22 is formed with a film thickness of 1 μm. Where this SiO
_{The two} films 22 had a film thickness variation of ± 8%. Next, as shown in FIG. 19B, a carbon film 23 having a thickness of 100 nm is formed on the SiO ₂ film 22 by a sputtering method using a graphite plate as a target.

Next, as shown in FIG. 19C, the carbon film 23
Positive photoresist on top (PFI15A manufactured by Sumitomo Chemical
A) 24 is applied and the photoresist (photosensitive resin layer) 24 is exposed using a mask pattern (not shown). At this time, the exposure wavelength λ is 365 nm. Next, in FIG.
As shown in (d), the photoresist 24 is developed to form a photoresist pattern 25.

Finally, as shown in FIG. 19E, the carbon film 23 and the insulating film 22 are patterned using the photoresist pattern 25 as a mask, and then the photoresist pattern 25 and the carbon film 23 are removed by ashing. ..

In the above method, the mask pattern is 0.5
Although contact hole patterns of μm □ and 0.7 μm □ were used, the dimensions of the pattern transferred to the photoresist 24 were 0.48 μm □ and 0.70 μm □, respectively. Further, the in-plane variation in the 6-inch wafer having the contact hole size of 0.70 μm was ± 1.8%.

For comparison, when the insulating film was patterned without providing a carbon film between the photoresist and the SiO ₂ film, a pattern resolution of 0.50 μm □ could not be obtained. The in-plane variation on a 6-inch wafer with a contact hole size of 0.70 μm is ± 8.8.
It was a very large percentage. The reason why such a result is obtained is as follows.

That is, since the light passing through the photoresist 24 is weakened in the carbon film 23, the substrate 21 or the substrate 2
The intensity of the light reflected by the metal wiring above 1 is sufficiently small.
Therefore, even if the film thickness of the insulating film 22 changes depending on the location and the phase of the reflected light deviates, the problem that the dimension of the resist pattern changes due to this does not occur.

Thus, according to the present embodiment, the distortion of the pattern transferred to the photoresist 24 is reduced, the resolution is improved, and the stable and uniform photo resist is obtained regardless of the film thickness of the SiO ₂ film 22. A resist pattern can be formed, so that the patterning of the SiO ₂ film 22 can be highly accurate and highly reliable.

In the present embodiment, the case of the SiO ₂ film as the translucent film to be processed has been described, but the same effect can be obtained in the case of other films such as a silicon nitride film and a resin film. Further, the base of the film to be processed is not limited to the Si substrate, but may be a metal film of Al, Ni, W, Cu or the like, metal wiring, or Al-Si-Cu, Al-Si, MoSi.
Other light reflecting films such as metal compound films such as x and WSix and metal compound wiring may be used.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the carbon film was formed by the sputtering method, but other film forming methods,
For example, it may be performed by a vacuum heating vapor deposition method or the like.

In the above embodiment, the case where the positive type photoresist is used has been described, but other resist materials may be used, and the negative type photoresist may be used. In this case, it is particularly effective when the exposure area is large, such as the opening pattern of the connection holes. Further, light having a wavelength of 365 nm was used as the exposure light, but the wavelength was 180 nm to 5 nm.
If the exposure light is in the range of 30 nm, the same effect as in the above embodiment can be obtained. In addition, various modifications can be made without departing from the scope of the present invention.

[0063]

As described above in detail, according to the present invention, since the carbon film is provided between the translucent film to be processed and the resist, the light passing through the resist is weakened in the carbon film. ..
As a result, the intensity of the reflected light of the exposure light becomes sufficiently small, and the abnormal exposure of the photosensitive resin layer due to the reflected light hardly occurs.

Therefore, since the distortion of the pattern transferred to the photosensitive resin layer can be suppressed, if the pattern of this photosensitive resin layer is used as a mask, the film to be processed is patterned with high accuracy.
Therefore, the reliability of the device and the manufacturing yield can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a step of forming a connection hole according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a step of forming a connection hole according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a step of forming an insulating film pattern according to the second embodiment of the present invention.

FIG. 4 is a sectional view of a step of forming an insulating film pattern according to a second embodiment of the present invention.

FIG. 5 is a wiring pattern formed by the method of the second embodiment.
The figure which shows the top view of an engine compared with that in the case of the conventional method.

FIG. 6 is a characteristic diagram showing the relationship between the film thickness and the reflectance of a SiO ₂ film formed on a polysilicon film when the carbon film has a film thickness of 0 nm.

FIG. 7 is a characteristic diagram showing the relationship between the film thickness of an SiO ₂ film formed on an Al film and the reflectance when the film thickness of the carbon film is 0 nm.

FIG. 8 is a characteristic diagram showing the relationship between the film thickness of the SiO ₂ film formed on the polysilicon film and the reflectance when the film thickness of the carbon film is 20 nm.

FIG. 9 is a characteristic diagram showing the relationship between the film thickness of an SiO ₂ film formed on an Al film and the reflectance when the film thickness of the carbon film is 20 nm.

FIG. 10 is a characteristic diagram showing the relationship between the reflectance and the thickness of the SiO ₂ film formed on the polysilicon film when the thickness of the carbon film is 40 nm.

FIG. 11 is a characteristic diagram showing the relationship between the film thickness of the SiO ₂ film formed on the Al film and the reflectance when the film thickness of the carbon film is 40 nm.

FIG. 12 is a characteristic diagram showing the relationship between the film thickness of an SiO ₂ film formed on a polysilicon film and the reflectance when the carbon film has a film thickness of 60 nm.

FIG. 13 is a characteristic diagram showing the relationship between the film thickness of an SiO ₂ film formed on an Al film and the reflectance when the carbon film has a film thickness of 60 nm.

FIG. 14 is a characteristic diagram showing the relationship between the film thickness of an SiO ₂ film formed on a polysilicon film and the reflectance when the carbon film has a film thickness of 80 nm.

FIG. 15 is a characteristic diagram showing the relationship between the film thickness of an SiO ₂ film formed on an Al film and the reflectance when the carbon film has a film thickness of 80 nm.

FIG. 16 is a characteristic diagram showing the relationship between the film thickness of an SiO ₂ film formed on a polysilicon film and the reflectance when the carbon film has a film thickness of 100 nm.

FIG. 17 is a characteristic diagram showing the relationship between the film thickness of an SiO ₂ film formed on an Al film and the reflectance when the carbon film has a film thickness of 100 nm.

FIG. 18 is a characteristic diagram showing the relationship between the light absorption rate of the carbon film and the film thickness of the carbon film.

FIG. 19 is a sectional view of a step of forming an insulating film pattern according to the third embodiment of the present invention.

FIG. 20 is a sectional view of a conventional process of forming a connection hole.

FIG. 21 is a sectional view of a conventional connection hole forming process.

FIG. 22 is a process cross-sectional view showing a conventional insulating film patterning method.

FIG. 23 is a process sectional view showing a conventional method of patterning an insulating film.

[Explanation of symbols]

1, 11, 21, substrate ... 2, 4, 12, 13, 15, 2
2 ... SiO ₂ film, 3 ... Al wiring, 5, 16, 23 ... Carbon film, 6, 17, 24 ... Photoresist, 14 ... Polysilicon film, 18 ... Disconnection part, 25 ... Photoresist pattern
N.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiji Horioka 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Stock company Toshiba Research Institute

Claims (1)

[Claims] 1. A step of forming a translucent film to be processed on a light reflecting film, a step of forming a carbon film on this film to be processed, and a photosensitive resin layer formed on this carbon film. A step of patterning the photosensitive resin layer by exposing and developing a desired pattern to the photosensitive resin layer, and etching the carbon film using the photosensitive resin layer as a mask. And a step of etching the film to be processed using the photosensitive resin layer or the carbon film as a mask, the film thickness d of the carbon film, the extinction coefficient k of the carbon film, and the exposure light A method of manufacturing a semiconductor device, characterized in that the relationship with a wavelength λ is set to 0.17 ≦ kd / λ.