JPH1131650A - Antireflection coating, substrate to be treated, manufacture of the substrate to be treated, manufacture of fine pattern and manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a fine pattern on a substratum substrate even as a single-layer film, without the need for the strict control operation of a film thickness by a method, wherein an antireflection coating is formed to be not of a reflection-type structure, which depends on a film thickness but of an absorption-type structure which depends on a damping coefficient. SOLUTION: When an antireflection coating 3 which is composed of SiOx Ny (oxynitride silicon) is formed on a substratum substrate, the flow rate ratio of N2 O (nitrous oxide) to SiH4 (monosilane) is gradually increased from the start of a film formation operation until the end of the film formation operation. It is formed into one-time film formation process, the concentration grade for Si atoms is created in the depth direction in a formed single-layer film, and a grade in which a damping coefficient (k) becomes continuously large toward a film rear 3b as an interface to the substratum substrate from a film surface 3a. When a k-value gradient is formed in the film, incident light L is absorbed and reflected repeatedly so as to be attenuated gradually in the film, and it is absorbed before it reaches the surface of the substratum substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an antireflection film, a substrate to be processed, a method of manufacturing a substrate to be processed, a method of manufacturing a fine pattern, and a method of manufacturing a semiconductor device. In addition, the present invention relates to an absorption-type antireflection film that absorbs light in a film, and a device using the antireflection film.

[0002]

2. Description of the Related Art As the degree of integration of a semiconductor device increases, the minimum processing size of the device is rapidly reduced.
For example, 0.35-0.
Mass production of 64 MDRAM, which has a design rule of about 40 μm, has been performed. However, in order to comply with subsequent design rules, it is necessary to further shorten the wavelength of the light source. Therefore KrF (248 nm), A
Lithography using an excimer laser such as rF (193 nm) as a light source is being introduced to mass production.

However, as the wavelength of the light source becomes shorter, the reflectance of the underlying substrate increases, and by using a single wavelength, the standing wave effect due to multiple interference in the resist film cannot be ignored. For this reason, in photolithography for forming a fine pattern of 0.35 μm or less, antireflection for weakening light reflected from the underlying substrate in order to prevent a decrease in contrast and resolution due to the effects of harlation and standing waves. A membrane is required. The principle of the anti-reflection coating is to shift the phase of the reflected light according to the film thickness and to match the amplitude ratio with the extinction coefficient k, and to cancel the incident light by the reflected light. Therefore, in the antireflection film, the control of the film thickness together with the k value is very important.

As an anti-reflection film material, a-S
i (amorphous silicon), TiON (titanium oxynitride), TiN (titanium nitride) and the like have been used in many cases, but SiO _x exhibiting very good optical characteristics in the far ultraviolet region used in excimer laser lithography in recent years. N _y
Are (silicon oxynitride) is of interest, Al (aluminum), p-Si (polysilicon), WSi _x (tungsten silicide), SiO below the deep UV chemically amplified resist a highly reflective base substrate, such as _x N By depositing a _y film or the like and suppressing the reflection of light from the base substrate, the finest gate processing process is realized (for example, Japanese Patent Application Laid-Open No. 7-201825).

However when performing the process using an antireflection film using the SiO _x N _y, the SiO _x N _y satisfies always an antireflection condition which varies by the thickness of the underlying substrate material, and deep UV chemically amplified resist Must be. The antireflection condition is a condition that minimizes the amplitude ratio of a standing wave formed in the resist film by the incident light due to the exposure. As shown in FIG. 9, the horizontal axis represents the thickness of the resist film, and the vertical axis represents the amount of light absorbed in the resist film. A swing curve of the absorbed light amount in the resist film with respect to the film thickness is created, and the film thickness at which the value of the absorbed light amount becomes minimum is obtained.
The condition under which the value of the amount of absorbed light is minimal is the condition under which the standing wave effect is minimized. The optimization of the optical constant of the antireflection film greatly affects the antireflection condition because the phase of the swing curve changes depending on the optical constants (refractive index n, extinction coefficient k, film thickness d) of the antireflection film.

[0006]

In order to realize a fine pattern, it is necessary to satisfy the reflection conditions (n, k, d) of the antireflection film with respect to the underlying substrate material and the photoresist film.
In the case of an antireflection film using a SiO _x N _y (silicon oxynitride) film, the film is formed using an apparatus such as plasma CVD. At this time, the refractive index n and the extinction coefficient k are set to Si under constant plasma CVD conditions (pressure, power, etc.).
It is determined only by the flow ratio between H ₄ (monosilane) and N ₂ O (nitrous oxide). Therefore, the film thickness d, which is the remaining reflection condition, is important for optimizing the anti-reflection conditions, and the phase may be adjusted by the film thickness, and very strict control is required. However, it is difficult to strictly control the film thickness d, and it is particularly difficult to control the film thickness of the antireflection film on the step underlying substrate. Further, when the material of the base substrate changes, the reflection conditions of the antireflection film change, so that the film cannot be formed by a single process, and the film formation process needs to be changed according to the material of the base substrate.

[0007] Therefore, a recent report has stated that several layers, ie, three layers of antireflection films having different extinction coefficients k, for example, three layers (k =
0.24, 0.45, 1.00) and a method of realizing an antireflection film by continuously absorbing incident light in the three layers (A Multilayer).
inorganic antireflective system for use in 248nmde
ep ultraviolet lithography (J.Vac.Tecnol.B14 (6) Nov /
Dec 1996 p4229-4233)).

This method absorbs light in the film and does not cancel out the phase by shifting the phase with the film thickness. Therefore, strict film thickness control is not required, and light is absorbed before reaching the underlying substrate. Therefore, it can be said that the film can be formed by a single process irrespective of the material of the base substrate, which is an effective method. However, unlike a single layer, a three-layer or multi-layer CVD process cannot be realized by a single process, and thus has a disadvantage that the throughput of a semiconductor manufacturing process is extremely deteriorated.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide an antireflection film having a high antireflection function without requiring strict film thickness control while being a single-layer film. The present invention provides a substrate to be processed, a method of manufacturing a substrate to be processed, a method of manufacturing a fine pattern, and a method of manufacturing a semiconductor device.

[0010]

According to a first aspect of the present invention, there is provided an antireflection film formed of a single-layer film and having an extinction coefficient increasing in a depth direction of the single-layer film. The extinction coefficient is increased in the depth direction of the anti-reflection film, and the absorption type structure that absorbs and reflects light repeatedly in the film to attenuate light gradually is used. Unlike a reflection type anti-reflection film that cancels incident light, it is possible to effectively prevent light reflection that requires strict film thickness control while having a simple structure of a single layer film. The mode of increase of the extinction coefficient is preferably a monotonic increase from the viewpoint of continuously absorbing light.

According to a second aspect of the present invention, in the anti-reflection film, the anti-reflection film is made of SiO _x N _y (silicon oxynitride), SiN _x
(Silicon nitride) or SiO _x (silicon oxide), and the concentration of Si in the constituent elements correlated with the extinction coefficient increases in the depth direction. When the antireflection film is made of the above-described material, it exhibits very good optical characteristics in a short-wavelength deep ultraviolet region such as an excimer laser, so that reflection of light from the surface layer of the underlying substrate can be more effectively prevented.

The substrate to be processed according to a third aspect of the present invention is one in which the antireflection film is formed on a base substrate. Since the incident light is absorbed before reaching the base substrate, the substrate to be processed having a large antireflection effect can be obtained without being affected by the material of the base substrate formed below the antireflection film.

According to a fourth aspect of the present invention, the substrate to be processed further comprises a photoresist film formed on the antireflection film.
Since the extinction coefficient of the anti-reflection film has changed, when light transmitted through the photoresist film is incident on the anti-reflection film, the light is absorbed in the anti-reflection film, so that there is no light reflected on the underlying substrate. A good anti-reflection effect with little standing wave effect can be obtained. Since a good antireflection effect is obtained, a fine pattern having stable dimensions and shapes can be formed.

According to a fifth aspect of the present invention, in the method of manufacturing a substrate to be processed, a raw material gas containing nitrogen or oxygen and a raw material gas containing silicon are caused to flow to form a silicon-based inorganic film containing nitrogen or oxygen on the base substrate. Forming a formed anti-reflection film, and in forming the anti-reflection film, increasing the flow ratio of the source gas containing nitrogen or oxygen to the source gas containing silicon in a single film forming step. By doing so, the Si concentration of the antireflection film formed on the base substrate is continuously reduced in the film forming direction.

It is only necessary to perform a simple flow rate control of changing the flow rate ratio of the source gas containing nitrogen or oxygen to the source gas containing silicon, and it is not necessary to strictly control the film thickness. The substrate to be processed can be easily manufactured.

According to a sixth aspect of the present invention, there is provided a method of manufacturing a fine pattern, comprising the steps of: forming a photoresist film on the anti-reflection film; Exposure using short-wavelength light such as, a step of transferring a mask pattern to a resist film by performing development, and etching the base substrate using the resist film to which the mask pattern has been transferred as a mask,
Transferring a mask pattern to a base substrate.

Since the extinction coefficient of the anti-reflection film changes continuously, when light transmitted through the photoresist enters the anti-reflection film during exposure of the photoresist film, the light continuously flows through the anti-reflection film. Is absorbed, so that no light is reflected from the underlying substrate and reaches the resist. Therefore, as in the reflection type anti-reflection film process, in order to cancel the phase of the reflected wave from the underlying substrate with the incident wave, a very strict thickness control of the anti-reflection film for adjusting the phase of the reflected wave is performed. Eliminates the need. Since reflection of light can be effectively prevented, a fine mask pattern having a stable size and shape can be formed. Using the photoresist film to which the mask pattern has been transferred as a mask, the underlying substrate is etched and the mask pattern is transferred to the underlying substrate, whereby a fine pattern having stable dimensions and shapes can be formed. In addition, since the antireflection film can be formed by a single growth, the throughput is good.

According to a seventh aspect of the present invention, in the method of manufacturing a semiconductor device, the method of manufacturing a fine pattern is used in a semiconductor manufacturing process. Since a fine pattern can be easily manufactured, a highly integrated semiconductor device can be easily obtained.

As described above, the antireflection film of the present invention is a single-layer film formed by one-time CVD, but has a concentration gradient of Si atoms in the depth direction of the film, whereby the single-layer film has The extinction coefficient k is increased in the depth direction. Despite being a single-layer anti-reflection film, it continuously absorbs incident light in the film, so there is no need to strictly control the film thickness for phase adjustment of the reflected light, and the surface layer of the underlying substrate is not required. The function as a good antireflection film can be realized by a single process without being affected by the material. Therefore, when the anti-reflection film of the present invention is used, next-generation fine pattern processing with a stable shape and dimensions of 0.25 μm or less can be easily realized. Next, the principle of the antireflection film will be described more specifically.

In the case of an anti-reflection film using a SiO _x N _y (silicon oxynitride) film, the film is formed by using an apparatus such as a parallel plate type plasma CVD. In this case, the refractive index n and the extinction coefficient are used. k is a constant plasma CVD condition (pressure,
Power, etc.), SiH ₄ (monosilane) and N ₂
It is determined only by the flow ratio with O (nitrous oxide).

Therefore, in the case of a conventional single-layer anti-reflection film for adjusting the phase of the reflected light, a constant optical constant is used as a target and constant CVD conditions (pressure, power, film formation time, SiH CVD is performed at ₄ flow rates and N ₂ O flow rate).

Here, the above-mentioned optical constants mean n, k, and d (film thickness), for example, W covered with an oxide film of 170 nm.
In the case of the antireflection film condition on Si, n = 2.1 and k =
The value is 0.54 and the film thickness d = 29 nm. The value differs from the above-mentioned CVD conditions depending on the type of plasma CVD, but means various conditions such as pressure, power, film formation time, SiH ₄ flow rate and N ₂ O flow rate. . When a conventional single-layer antireflection film is formed, these optical constants and CVD conditions are always constant during the film formation and are not changed.

In the case of an antireflection film condition on Al covered with a 170 nm oxide film, the above optical constant is n = 2.1,
k = 0.87 and d = 24 nm. K at N ₂ O flow rate
Can be freely changed by the film formation time. Of the above conditions for the antireflection film on the WSi, if only the N ₂ O flow rate and the film formation time are changed and the other conditions are not changed, A constant is obtained.

From this, it can be seen that the extinction coefficient k is a variable of the N ₂ O flow rate, and the film thickness d is a variable of the film formation time. Therefore, in order to realize the antireflection film of the present invention, only the N ₂ O flow rate is changed among the CVD conditions, and the extinction coefficient k (FIG. 3) and the film formation rate (FIG. 4) at each N ₂ O flow rate are changed. After an experiment, a function of the N ₂ O flow rate during CVD and the film forming time is calculated by calculation so that the gradient of the extinction coefficient in the depth direction of the antireflection film is constant (FIG. 5). That is, the experimental data of N ₂ O flow rate vs. k and the experimental data of N ₂ O vs. deposition rate are approximated. The total film thickness and the gradient of the k value are set from the two approximate expressions, and the horizontal axis represents the film forming time (m
in), and the vertical axis is obtained by integrating a time schedule with the N ₂ O flow rate (sccm) by a computer.

CV according to this time schedule
By increasing the flow rate of N ₂ O during D, it is possible to realize an antireflection film in which the extinction coefficient k increases with a constant gradient in the depth direction from the surface of the antireflection film.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for producing a fine pattern according to the present invention will be described below. Here, the case where the antireflection film is made of SiO _x N _y will be described.

To transfer a pattern onto an underlying substrate such as silicon (Si), the following photography technique is used. As shown in FIG. 8, SiO _x N
_An anti-reflection film 3 composed of a _y film is formed, and a far ultraviolet chemically amplified resist film 4 is formed on the anti-reflection film 3 (FIG. 8A). The resist film 4 is exposed and developed using excimer laser light L, and the mask pattern 5 is transferred to the resist film 4 (FIG. 8B). Using the resist film 4 to which the mask pattern 5 has been transferred as a mask, the base substrate 1 is etched together with the antireflection film 3 to form the base substrate 1
Then, the mask pattern 6 is transferred (FIG. 8C). The surface layer of the base substrate 1 to be etched is, in particular, Al, p-S
i, when made of a conductive interconnect material such as WSi _x,
High reflectivity. A substrate to be processed is constituted by the base substrate 1 on which the antireflection film 3 is formed and the base substrate 1 on which the resist film 4 and the antireflection film 3 are formed.

The SiO _x N _y film, which is an antireflection film, is a single-layer film formed by one-time CVD, using a parallel plate type plasma CVD apparatus and using SiH ₄ as a source gas.
(Monosilane) and N ₂ O (nitrous oxide). In the present embodiment, when forming a SiO _x N _y film, SiH ₄
By increasing the flow ratio of N ₂ O to the substrate, the Si concentration of the antireflection film 3 formed on the base substrate 1 is continuously reduced in the film forming direction. Therefore,
Film formation conditions for forming such an antireflection film are determined.

First, using a parallel plate type plasma CVD apparatus PV-XP (manufactured by Kokusai Electric), SiO _x N _y was used.
At the time of film formation, an experimental result with respect to the N ₂ O flow rate of the extinction coefficient k at 248 nm measured using a spectroscopic ellipsometer was obtained (FIG. 3), and the film formation rate at this time was obtained (FIG. 3). 4). The flow rate of N ₂ O is controlled by a mass flow controller (MFC).

As can be seen from FIGS. 3 and 4, 248 nm
Far ultraviolet light in the extinction coefficient k and the deposition rate of a variable of the respective N ₂ O flow rate can be approximated by the least squares method as a function of N ₂ O flow rate, respectively. The approximate expression is shown in the figure.

A simulation was performed using a SiO _x N _y film whose extinction coefficient k continuously changes as shown in FIG. 2 as a model. The simulation is performed by gradually increasing the N ₂ O flow rate from the initial stage of film formation during plasma CVD using the approximate expressions shown in FIGS. The concentration of atoms was reduced so that the extinction coefficient k became 0 on the film surface.

The model of the anti-reflection film 3 of FIG. 2, SiO _x
The extinction coefficient k continuously decreases at a constant gradient from the back surface 3b to the front surface 3a of the N _y film. The density of black and white is the magnitude of the k value (the light value is lower, and the k value is higher as light to darker). Is higher), that is, the magnitude of the concentration of Si atoms.

FIG. 1 shows the principle of the continuous light absorption of the above-mentioned SiO _x N _y film, and shows how incident light is continuously absorbed in the SiO _x N _y film. Solid arrows indicate incident light, and dotted arrows indicate light absorbed and canceled in the anti-reflection film 3. Light incident on the anti-reflection film 3 is continuously absorbed before reaching the underlying substrate, thereby preventing reflection on the upper photoresist film.

The principle of anti-reflection is as follows. As the value of the extinction coefficient k, which is the light absorption coefficient, increases, the light absorption increases, but the light reflection also increases. That is, light absorption is high at the same time as light absorption is high. Therefore, a gradient of the k value is provided in the film, the reflection is eliminated on the surface of the film with the k value being zero, and the k value increases toward the back surface of the film. Light is gradually absorbed and reflected in the film, and the light is attenuated by increasing the amount of absorption and reflection, so that the light is absorbed before reaching the underlying substrate.

Next, in order to determine the film thickness of the antireflection film in which the extinction coefficient k changes continuously, the time schedule during the film formation with the N ₂ O flow rate (FIG. 5) and the film formation amount at that time (FIG. 5) FIG. 6) was obtained by simulation. FIG.
_x N _y film thickness of 1000 Å (hereinafter, simply [A] and represents Angstroms) of showing the N ₂ O time schedule at the time of film formation by plasma CVD was obtained by simulation when normalized to. Where S
The iH ₄ flow rate was kept constant at 60 sccm. At the start of film formation on the underlying substrate, the N ₂ O flow rate is 1 sccm, that is, k =
As 2.1, increase the concentration of Si atoms. The flow rate of N ₂ O gradually increases to decrease the concentration of Si atoms. At the end of film formation, the concentration of Si atoms is 33 atm%, that is, k =
0 SiO ₂ . In the embodiment, the simulation is performed by setting the extinction coefficient k to 0 on the film surface and to 2.1 at the interface with the underlying substrate, that is, Δk = 2.1 / 1000 [A].

As shown in FIG. 6, by multiplying the time schedule obtained in FIG. 5 by n times, the thickness d of the SiO _x N _y film can be freely set. Therefore, the film thickness required in terms of the energy of light transmitted through the resist film and incident on the antireflection film out of the exposure energy of the stepper at the time of resist exposure can be set as required. Further, the gradient of the extinction coefficient k can be easily changed by calculation. FIG. 6 shows 400 [A] to 4000 [A].
The results of film thickness measurement by length-measuring SEM when the film was formed with the film thickness set by simulation between
It can be seen that the two values completely match between [A] and 3000 [A].

FIG. 7 shows SiO _x N _{y formed} to a thickness of 800 [A] in order to examine the concentration distribution of Si atoms in the film.
3 shows the results of XPS (X-ray photoelectron spectroscopy) of the film. It can be seen that the composition ratio of Si atoms increases in the depth direction from the film surface a. As a result, a result according to the simulation was obtained, and it was confirmed that a desired antireflection film could be formed based on the simulation.

As described above, according to the antireflection film of the embodiment, the light transmitted through the resist film continuously absorbs the light until it reaches the underlying substrate. It is not affected by the standing wave effect due to the standing wave effect due to the difference in the thickness of the photoresist on the stepped substrate due to the standing wave, and it is possible to realize a fine pattern processing which is faithful to dimensional accuracy and has a good shape. Since fine pattern processing with a good shape and faithful to dimensional accuracy can be realized, light having a wavelength of 248 nm or shorter, for example, A
An rF excimer laser (193 nm) can be used.

Further, according to the embodiment, in order to give a gradient to the k value, the flow rate ratio between SiH ₄ and N ₂ O may be simply controlled, and a conventional type of anti-reflection type in which the phases of reflected waves are matched. It does not require very strict film thickness control unlike a film. Furthermore, since it is a light absorption type anti-reflection film and is composed of a single layer film, it can be formed by a single CVD, and has a higher throughput than a conventional process using a three-layer anti-reflection film. Moreover, the throughput does not deteriorate as compared with the conventional process using a single-layer antireflection film.

[0040]

EXAMPLES In fact, the surface layer material Al, W, WSi _x,
On a highly reflective base substrate composed of p-Si, respectively,
Using a parallel plate plasma CVD apparatus PV-XP (manufactured by Kokusai Electric Inc.), an SiO _x N _y film having a thickness of 800 [A] is formed, and a deep UV chemically amplified resist XP- is further formed thereon.
8843 (manufactured by Shipley Co., Ltd.) and a 0.25 μm L / S (line and space) using a KrF excimer laser stepper NSR-1505EX1 (manufactured by Nikon)
When the pattern was processed, a fine pattern with stable dimensions and shapes could be realized on any of the base substrates. Also, on the stepped patterns of the above four types of base substrates, L / S of 0.25 μm could be similarly processed with stable dimensions and shapes.

[0041]

According to the present invention, the antireflection film continuously absorbs light before the light transmitted through the resist film passes through the antireflection film and reaches the underlying substrate. Therefore, a fine pattern processing with good shape and faithful to the dimensional accuracy can be realized without being affected by the standing wave effect accompanying the above and the standing wave effect due to the difference in the photoresist film thickness on the step-underlying substrate.

Further, it is only necessary to control the flow rate ratio of the raw material gas for the anti-reflection film, and it is not necessary to control the film thickness strictly as in the conventional anti-reflection film of the type that matches the phase of the reflected wave. Easy. In addition, although it is a light absorption type antireflection film, it is not a multilayer film but a single layer film,
The film can be formed by a single growth, and the throughput is not deteriorated as compared with the conventional process using a single-layer antireflection film. Further, since it is not affected by the base substrate material, the film can be formed by a single process regardless of the base substrate material.

[Brief description of the drawings]

FIG. 1 is a diagram modeling and representing the principle of continuous light absorption of an antireflection film in an embodiment.

FIG. 2 is a model diagram of an antireflection film according to an embodiment, in which the shade of color indicates the magnitude of the k value changing in the depth direction, that is, the magnitude of the concentration of Si atoms.

FIG. 3 shows the relationship between the flow rate of the SiO _x N _y film and the flow rate of N ₂ O when the SiO _x N _y film was formed using the plasma CVD apparatus.
It is a figure showing the change of the extinction coefficient k at 8 nm.

FIG. 4 is a diagram illustrating a change in the film forming speed of the SiO _x N _y film with respect to the N ₂ O flow rate when the SiO _x N _y film is formed using the plasma CVD apparatus.

FIG. 5 is a time schedule diagram of the N ₂ O flow rate at the time of film formation by plasma CVD determined by simulation by normalizing the thickness of the SiO _x N _y film to 1000 [A].

FIG. 6 shows a film thickness based on a simulation result and a length measurement SEM of a film actually formed based on the simulation result.
FIG. 7 is a comparison diagram of the results of measuring the film thickness according to FIG.

FIG. 7 is a diagram showing a composition ratio result of XPS (X-ray photoelectron spectroscopy) of a SiO _x N _y film formed to a thickness of 800 [A].

FIG. 8 is a process chart of a pattern manufacturing method for transferring a pattern onto a base substrate such as a semiconductor.

FIG. 9 is a characteristic diagram of the absorbed light amount in the resist film with respect to the resist film thickness showing the standing wave effect.

[Explanation of symbols]

 Reference Signs List 1 base substrate 3 anti-reflection film 4 photoresist film 6 pattern

Claims (7)

[Claims] An anti-reflection film formed of a single-layer film and having an extinction coefficient increasing in a depth direction of the single-layer film. 2. The antireflection film is made of SiO _x N _y (silicon oxynitride), SiN _x (silicon nitride), or Si
The antireflection film according to claim 1, wherein the antireflection film is made of O _x (silicon oxide), and a Si concentration in a constituent element correlated with the extinction coefficient increases in a depth direction. 3. A substrate to be processed, wherein the antireflection film according to claim 1 is formed on a base substrate. 4. The substrate according to claim 3, further comprising a photoresist film formed on said anti-reflection film. 5. A step of forming an antireflection film made of a silicon-based inorganic film containing nitrogen or oxygen on a base substrate by flowing a source gas containing nitrogen or oxygen and a source gas containing silicon. When the antireflection film is formed, the film is formed on the base substrate by relatively increasing the flow ratio of the source gas containing nitrogen or oxygen to the source gas containing silicon in one film forming step. A method for manufacturing a substrate to be processed, wherein the Si concentration of the anti-reflection film continuously decreases in the film forming direction. 6. The method for manufacturing a substrate to be processed according to claim 5, further comprising: forming a photoresist film on the antireflection film; and applying a short-wavelength light such as excimer laser light to the resist film. Exposing and developing the resist pattern to transfer a mask pattern to the resist film, and using the photoresist film to which the mask pattern has been transferred as a mask, etching the base substrate and transferring the mask pattern to the base substrate. A method for producing a fine pattern comprising: 7. A method for manufacturing a semiconductor device, wherein the method for manufacturing a fine pattern according to claim 6 is used in a semiconductor manufacturing process.