JP2004296840A - Method and system for forming resist pattern, and layer forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the necessity of developing a different resist for each mask by using the photoresist of the same kind for both a photomask having a punched pattern and another photomask having a solid pattern, and by obtaining a resist pattern having a rectangular shape even when the photomask having any pattern, either a punched pattern or a solid pattern, is used when the resist pattern is formed. <P>SOLUTION: A resist pattern forming system 100 is equipped with an exposure system 120 which subjects the prescribed region of a photoresist layer to an exposure process through a photomask with an opening, a layer forming unit 110 which forms the photoresist layer exposed to light through the above exposure system 120 varying its thickness corresponding to the area ratio of the opening, and a resist pattern forming unit 130 which forms the resist pattern on the basis of the photoresist layer which has been subjected to an exposure process through the exposure system 120. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a resist pattern forming system or layer forming apparatus, and a method in the above system or apparatus. In particular, the present invention relates to a field related to a method of forming a resist pattern in semiconductor fine processing.
[0002]
[Prior art]
In forming a fine pattern using a photoresist and light for fine processing of a semiconductor, a pattern on a photomask is exposed, developed, and transferred to the resist. At that time, there are many openings (portions through which the exposure light is transmitted at the time of exposure) of the photomask (50% or more), that is, a so-called remaining pattern (when the resist is a positive type) and a small number of openings in the photomask ( It is known that the shape of the resist pattern after development differs from the so-called (when the resist is a positive type) blank pattern.
[0003]
[Problems to be solved by the invention]
Considering the case of a positive resist, in the case of the remaining pattern, since the opening of the photomask is large, light is scattered around the opening around the mask pattern, and the contrast is lower than that of the removal pattern. Therefore, when the resist pattern is formed in the remaining pattern, there is a problem that the thickness of the resist head is reduced and the pattern head is rounded. Therefore, conventionally, a separate resist suitable for each mask has been developed for the blank pattern and the remaining pattern. Therefore, development cost and time have increased, and the cost has also increased due to the increase in the type of resist. In the case of a negative resist, the reverse is the case of a positive resist. When exposure is performed using a photomask having a large ratio of openings, the pattern head is stretched due to the effect of lowering the contrast due to the effect of lowering the contrast. There was a problem that it became a -top shape.
[0004]
By the way, semiconductors have recently been miniaturized, and accordingly, the wavelength of light at the time of exposure has been decreasing year by year. Examples of the exposure wavelength, 248 nm (KrF laser), 193 nm (ArF laser), 157 nm _{(F 2} laser), and a 13 nm (EUV light). The feature size is miniaturized, the resist film thickness in accordance with the exposure wavelength becomes shorter and thinner, the resist film thickness is typically 300nm or less in the case of ArF exposure, in the case of F ₂ exposure becomes 200nm or less I have. With such miniaturization and thinning of the resist, the influence of the difference in contrast between the above-mentioned punched pattern and the remaining pattern is increasing, and the cost burden when developing a resist according to the mask is increasing year by year. , The development period is also long. If the same resist can be used for the blanking pattern and the remaining pattern, the development cost of the resist can be reduced, the development time can be shortened, and the type of resist can be reduced, which is a great advantage for reducing the device development cost and shortening the development time. There is.
[0005]
In the present invention, in the formation of a resist pattern, the same type of photoresist is used in the case where the photomask is a blank pattern and the case where the photomask is a remaining pattern, and a rectangular shape is obtained in both patterns, so that each mask can be obtained. It aims to eliminate the need to develop a different resist.
[0006]
[Means for Solving the Problems]
A method of forming a resist pattern according to the present invention includes an exposure step of exposing a predetermined region of a photoresist layer using a photomask having an opening,
A layer forming step of forming a photoresist layer to be exposed in the exposure step, by changing the thickness of the layer according to a ratio of an opening portion of the photomask used in the exposure step,
A resist pattern forming step of forming a resist pattern based on the photoresist layer exposed in the exposing step.
[0007]
The photoresist layer, the light reflectance of the light exposed by the exposure step changes depending on the film thickness,
The layer forming step includes forming a photoresist layer having a light reflectance higher than a predetermined value when the ratio of the openings is 50% or more, and forming the photoresist layer with a ratio of the openings smaller than 50%. Preferably, a photoresist layer having a light reflectance smaller than the predetermined value is formed.
[0008]
The method of forming a resist pattern according to the present invention includes a layer forming step of forming a photoresist layer on a film to be processed on a substrate,
An exposure step of exposing a predetermined pattern to a predetermined region of the photoresist layer formed by the layer forming step, using a photomask having a predetermined pattern formed by the opening, having an opening;
A resist pattern forming step of forming a resist pattern based on the photoresist layer on which the predetermined pattern has been exposed by the exposure step,
The layer forming step, in the case of exposing the pattern having a large proportion of the opening portion of the photomask by the exposure step, and in the case of exposing the pattern having a small proportion of the opening portion of the photomask by the exposure step, The thickness of the photoresist layer is changed.
[0009]
The method of forming a resist pattern includes the step of forming the photoresist with a thickness of the photoresist at which the light reflectance is maximized based on the dependency of the thickness of the photoresist on the light reflectance from the photoresist at the time of exposure, which is obtained in advance by simulation. A pattern having a large proportion of openings in the mask is exposed by the above-described exposure step, and a pattern having a small proportion of openings in the photomask is exposed by the above-described exposure step at a thickness of the photoresist in which the light reflectance is minimal. It is characterized by the following.
[0010]
The thickness of the photoresist layer is 300 nm or less.
[0011]
The exposing step is to selectively irradiate a predetermined area of the photoresist layer with an energy ray for exposure,
KrF laser light is used as the energy ray.
[0012]
The exposing step is to selectively irradiate a predetermined area of the photoresist layer with an energy ray for exposure,
An ArF laser beam is used as the energy ray.
[0013]
The exposing step is to selectively irradiate a predetermined area of the photoresist layer with an energy ray for exposure,
Light having a wavelength shorter than 160 nm is used as the energy ray.
[0014]
A resist pattern forming method according to the invention is characterized by the use of F ₂ laser beam as the energy beam.
[0015]
The resist pattern forming method according to the present invention is characterized in that light having a wavelength of 12 nm or more and 15 nm or less is used as the energy ray.
[0016]
A resist pattern forming system according to the present invention, an exposure unit that exposes a predetermined region of a photoresist layer using a photomask having an opening,
According to the proportion of the opening portion of the photomask used in the exposed portion, by changing the thickness of the layer, a layer forming portion to form a photoresist layer to be exposed by the exposed portion,
A resist pattern forming section for forming a resist pattern based on the photoresist layer exposed by the exposure section.
[0017]
The layer forming apparatus according to the present invention is a layer forming apparatus that forms a photoresist layer to be exposed by an exposure apparatus that exposes a predetermined region of the photoresist layer using a photomask having an opening,
The thickness of the layer is changed according to the ratio of the opening of the photomask used in the exposure apparatus, and a photoresist layer to be exposed by the exposure apparatus is formed.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be specifically described using embodiments, but the present invention is not limited to the following embodiments.
[0019]
Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a system according to the first embodiment.
In FIG. 1, the resist pattern forming system 100 includes a layer forming section 110 (an example of a layer forming apparatus), an exposing apparatus 120 (an example of an exposing section), and a resist pattern forming section 130. The layer forming section 110 has a coating device 111 and a heat treatment device 112. The resist pattern forming section 130 has a heat treatment device 131 and a development processing device 132. Here, in FIG. 1, the heat treatment apparatus 112 and the heat treatment apparatus 131 are configured as different apparatuses, but may be shared by one apparatus.
[0020]
FIG. 2 is a diagram showing a flowchart of the method for forming a resist pattern in the first embodiment.
In step S (step) 201, the layer forming unit 110 forms a photoresist layer to be exposed by the exposure device 120 in step S202. Here, when forming the photoresist layer, the layer forming section 110 changes the film thickness of the layer in accordance with the ratio of the opening of the photomask used in the exposure apparatus 120, and To form a photoresist layer to be exposed. As will be described later, the light reflectance of the light exposed in the exposure step varies depending on the thickness of the photoresist layer. Therefore, when the proportion of the opening is 50% or more, the layer forming section 110 forms a photoresist layer having a film thickness with the light reflectance larger than a predetermined value, and the proportion of the opening is greater than 50%. If it is smaller, a photoresist layer having a thickness with the light reflectance smaller than the predetermined value is formed.
[0021]
In step S202, the exposure device 120 exposes a predetermined region of the photoresist layer using a photomask having an opening.
[0022]
In step S203, the resist pattern forming unit 130 forms a resist pattern based on the photoresist layer exposed by the exposure unit.
[0023]
【Example】
First, to transfer a photomask pattern to a resist by exposing and developing the resist pattern, first, an anti-reflection film is formed on a film to be processed, and a photoresist is formed thereon.
FIG. 3 is a diagram showing the relationship between the reflectance of the exposure light from the resist and the resist film thickness.
In order to determine the appropriate thickness of the photoresist, first, the dependence of the reflectance of light from the resist surface on the thickness of the resist was calculated by simulation. FIG. 3 shows the calculation results when the exposure wavelength is 157 nm and the exposure NA is 0.85. It can be seen that the reflectivity changes periodically depending on the resist film thickness. The difference in the resist film thickness between the part where the reflectivity becomes maximum and the part where the reflectivity becomes minimum is a value obtained by dividing a quarter of the exposure wavelength by the refractive index of the resist at the exposure wavelength. That is, in this case, a value obtained by dividing 157 nm by 4 and dividing by a resist refractive index of 1.68, that is, 23 nm is obtained.
[0024]
FIG. 4 is a diagram showing an example of a resist cross-sectional shape when the resist film thickness is 122 nm, which is calculated from the optical image.
FIG. 5 is a diagram illustrating an example of a resist cross-sectional shape when the resist film thickness is 99 nm, calculated from an optical image.
FIG. 4 shows the cross-sectional shape of the resist calculated from the light intensity distribution in the vicinity where the reflectivity is maximized (resist film thickness 122 nm). FIG. 5 shows the cross-sectional shape of the resist calculated from the light intensity distribution in the vicinity where the reflectivity becomes minimum (resist film thickness 99 nm). The calculation was performed at the above exposure wavelength and NA, using an alternating type phase shift mask, and 90 nm 1: 1.
This is a case where a line and space pattern is formed. 4 and 5, the inside of the figure is the portion where the resist remains. In the case of a film thickness of 122 nm in FIG. 4, the resist pattern head is stretched and slightly T-top. On the contrary, in the case of a film thickness of 99 nm in FIG. It turns out that is round.
[0025]
Next, an actual resist pattern to be compared is prepared.
FIG. 6 is a diagram showing an example of a layer structure in which a silicon dioxide film, an antireflection film, and a resist layer are formed on a substrate.
First, the case where the resist film thickness is 122 nm will be described. As shown in FIG. 6, a silicon dioxide film 52 having a thickness of 200 nm is formed as a film to be processed on a silicon substrate 51, and a DUV30J film made by Brewer Science is formed thereon as an antireflection film 53. Specifically, a DUV30J film having a thickness of 85 nm is formed by spin-coating a solution of DUV30J with a spin coater and performing heat treatment at 205 ° C. for 90 seconds.
[0026]
Next, on the antireflection film 53 in FIG. 6, as a photoresist film 54, to form the Clariant _{F 2} positive resist FX-1000P membrane. Specifically, the FX-1000P film 54 having a thickness of 122 nm is formed by spin-coating the solution of FX-1000P with a spin coater as a coating device 111 and performing a heat treatment at 150 ° C. for 60 seconds in a heat treatment device 112. I do.
[0027]
Next, a predetermined region of the resist is selectively irradiated with an F ₂ laser beam by using an F ₂ microstepper manufactured by Excitech as the exposure device 120. The photomasks such as 25% of the opening is a whole, by using a mask so-called "bleeding", NA of the optical system is 0.85, F ₂ light on the condition that the illuminator sigma 0.70 ( (Wavelength: 157 nm). Note that the exposure amount is 20 mJ / cm ² .
[0028]
Next, the exposed wafer is taken out and subjected to a heat treatment at 130 ° C. for 90 seconds in a proximity-type closed oven as a heat treatment device 131.
[0029]
Next, the wafer that has been subjected to the heat treatment using the developing apparatus 132 is dipped in an aqueous solution containing 2.38% of tetramethylammonium hydroxide (TMAH) for 60 seconds, and then rinsed with pure water for 60 seconds.
[0030]
FIG. 7 is a diagram showing a resist pattern shape formed by exposure and development using a photomask having a low aperture ratio when the resist film thickness is 122 nm.
As a result, a resist pattern 64 as shown in FIG. 7 is formed. The resist line width is 90 nm. As can be seen from FIG. 4, the resist film thickness of 122 nm this time is a film thickness that easily stretches the head, and the aperture ratio of the photomask is low, so that the contrast is high and the head is easily stretched optically. For this reason, the resist pattern 64 is T-top with its head extended. Here, 61 is a silicon substrate, 62 is a silicon dioxide film, and 63 is an antireflection film.
[0031]
Next, a resist pattern is formed by the method for forming a resist pattern according to the first embodiment.
A resist pattern in which a mask having a resist film thickness of 122 nm and a large proportion of openings is used as a photomask is formed. First, a photoresist FX-1000P film having a thickness of 122 nm is formed by the layer forming part 110 as the photoresist film 54 in FIG.
[0032]
Next, with reference to Ekishitekku Co., Ltd. F ₂ micro stepper as an exposure apparatus 120 is selectively irradiated with F ₂ laser beam in a predetermined area of the resist. The photomasks such as 75% of the opening is a whole, by using a mask so-called "leaving", NA of the optical system is 0.85, F ₂ light on the condition that the illuminator sigma 0.70 ( (Wavelength: 157 nm). Note that the exposure amount is 16 mJ / cm ² .
[0033]
Next, the exposed wafer is taken out and subjected to a heat treatment at 130 ° C. for 90 seconds in a proximity type closed oven as the heat treatment device 131.
[0034]
Next, the wafer that has been subjected to the heat treatment is dipped in an aqueous solution containing 2.38% of TMAH for 60 seconds using the developing apparatus 132, and then rinsed with pure water for 60 seconds.
[0035]
FIG. 8 is a diagram showing a resist pattern shape formed by exposure and development using a photomask having a high aperture ratio when the resist film thickness is 122 nm.
As a result, a resist pattern 74 as shown in FIG. 8 is formed. The resist line width is 90 nm. The resist film thickness of 122 nm in this case should be such that the head is easily stretched as can be seen from FIG. 4, but the contrast is low and the head is likely to be optically round because the aperture ratio of the photomask is high. Therefore, the effects of the two cancel each other out, and the resist pattern 74 has a rectangular shape. Here, 71 is a silicon substrate, 72 is a silicon dioxide film, and 73 is an antireflection film.
[0036]
Next, a case where the resist film thickness is 99 nm will be described. First, as shown in FIG. 6, a silicon dioxide film 52 having a thickness of 200 nm is formed as a film to be processed on a silicon substrate 51, and a DUV30J film made by Brewer Science is formed thereon as an antireflection film 53. . Specifically, a DUV30J film having a thickness of 85 nm is formed by spin-coating a solution of DUV30J with a spin coater and performing heat treatment at 205 ° C. for 90 seconds.
[0037]
Next, on the antireflection film 53, a photoresist film 54, to form the Clariant _{F 2} positive resist FX-1000P membrane. Specifically, the FX-1000P solution is spin-coated with a spin coater as a coating device 111, and is subjected to a heat treatment at 150 ° C. for 60 seconds in a heat treatment device 112, so that the FX-1000P film having a film thickness of 99 nm as a resist pattern 84 is formed. A 1000P film is formed.
[0038]
Next, with reference to Ekishitekku Co., Ltd. F ₂ micro stepper as an exposure apparatus 120 is selectively irradiated with F ₂ laser beam in a predetermined area of the resist. The photomasks such as 25% of the opening is a whole, by using a mask so-called "bleeding", NA of the optical system is 0.85, F ₂ light on the condition that the illuminator sigma 0.70 ( (Wavelength: 157 nm). Note that the exposure amount is 18 mJ / cm ² .
[0039]
Next, the exposed wafer is taken out and subjected to a heat treatment at 130 ° C. for 90 seconds in a proximity-type closed oven as the heat treatment device 131.
[0040]
Next, the wafer after the heat treatment is dipped in an aqueous solution containing 2.38% of tetramethylammonium hydroxide (TMAH) for 60 seconds using the developing apparatus 132, and then rinsed with pure water for 60 seconds.
[0041]
FIG. 9 is a diagram showing a resist pattern shape formed by exposure and development using a photomask having a low aperture ratio when the resist film thickness is 99 nm.
As a result, a resist pattern 84 as shown in FIG. 9 is formed. The resist line width is 90 nm. As shown in FIG. 5, the resist film thickness of 99 nm this time should be such that the head is likely to be rounded, but since the aperture ratio of the photomask is low, the contrast is high and the head is easily optically stretched. Therefore, the effects of the two cancel each other out, and the resist pattern 84 has a rectangular shape. Incidentally, 81 is a silicon substrate, 82 is a silicon dioxide film, and 83 is an antireflection film.
[0042]
Next, a case where a mask with a resist film thickness of 99 nm and a large proportion of openings are used as a photomask will be described. First, similarly to the above case, a 99 nm-thick photoresist FX-1000P film is formed as the photoresist film 54 in FIG.
[0043]
Next, with reference to Ekishitekku Co., Ltd. F ₂ micro stepper as an exposure apparatus 120 is selectively irradiated with F ₂ laser beam in a predetermined area of the resist. The photomasks such as 75% of the opening is a whole, by using a mask so-called "leaving", NA of the optical system is 0.85, F ₂ light on the condition that the illuminator sigma 0.70 ( (Wavelength: 157 nm). Note that the exposure amount is 14 mJ / cm ² .
[0044]
Next, the exposed wafer is taken out and subjected to a heat treatment at 130 ° C. for 90 seconds in a proximity type closed oven as the heat treatment device 131.
[0045]
Next, the wafer after the heat treatment is dipped in an aqueous solution containing 2.38% of TMAH for 60 seconds using the developing apparatus 132, and then rinsed with pure water for 60 seconds.
[0046]
FIG. 10 is a diagram showing a resist pattern shape formed by exposing and developing using a photomask having a high aperture ratio when the resist film thickness is 99 nm.
As a result, a resist pattern 94 as shown in FIG. 10 is formed. The resist line width is 90 nm. As can be seen from FIG. 5, the resist film thickness of this time is such that the head is easily rounded, and since the aperture ratio of the photomask is high, the contrast is low and the head is easily optically rounded. Therefore, it can be seen that the head of the resist pattern 94 is rounded and the head is thinned. Incidentally, reference numeral 91 denotes a silicon substrate, 92 denotes a silicon dioxide film, and 93 denotes an antireflection film.
[0047]
From the above, in this embodiment mode, when exposure is performed using a photomask having a small ratio of an opening portion (a low opening ratio), a minimum portion of light reflectance from a resist, for example, a resist film thickness of 99 nm is used. In the case of performing exposure using a photomask having a high aperture ratio, by using the maximum portion of the light reflectance from the resist, for example, a resist film thickness of 122 nm, the same type of resist can be used to form a resist pattern shape in both masks. You can see that it can be made rectangular.
[0048]
FIG. 11 is a diagram showing resist pattern shapes after exposure and development when the aperture ratio of the photomask is high (left diagram) and when it is low (right diagram).
In FIG. 11, the left side 14 shows the resist pattern shape exposed and developed using a photomask having a high aperture ratio when the resist film thickness is 122 nm, and the right side 18 shows the aperture ratio when the resist film thickness is 99 nm. This is a resist pattern shape exposed and developed using a low photomask. Here, 11 and 15 are silicon substrates, 12 and 16 are silicon dioxide films, and 13 and 17 are antireflection films.
[0049]
As described above, in the first embodiment, the film thickness of the photoresist is changed depending on whether the photomask is a blank pattern or a left pattern. More specifically, in the case of a positive resist, the punched pattern has a small ratio of the opening of the photomask and thus has a high contrast and the head of the pattern is easily stretched. On the other hand, in the case of the remaining pattern, the contrast is low and the head of the pattern is easily lost. By changing the thickness of the photoresist, a rectangular resist pattern can be obtained for both the punched pattern and the remaining pattern even if the same type of photoresist is used.
[0050]
As described above, the method for forming a resist pattern according to the first embodiment includes the steps of forming a photoresist layer on a film to be processed on a substrate, and selectively applying energy rays such as light to a predetermined region of the photoresist. Irradiating and exposing, the step of heat-treating the exposed photoresist layer, and developing the heat-treated resist layer to selectively remove exposed or unexposed parts of the resist layer. Forming a fine pattern by exposing the opening of the photomask, that is, a pattern in which the proportion of the portion through which the exposure light passes during exposure, that is, a so-called remaining pattern, The method is characterized in that the thickness of the photoresist layer is changed between the case of exposing a pattern having a small number of portions, that is, the so-called blank pattern.
[0051]
In addition, the dependence of the light reflectance from the resist upon exposure on the resist film thickness is determined in advance by simulation, and the pattern is exposed with the resist film thickness at which the reflectance becomes maximum, and the resist film thickness at which the reflectance becomes minimum is obtained. And exposing the blank pattern.
[0052]
Further, the method of forming a resist pattern according to the present embodiment is characterized in that the thickness of the photoresist layer, which is particularly effective, is used at a thickness of 300 nm or less.
[0053]
As the energy beam, the effect is in accordance with the respective specifications as conspicuous, KrF laser light, ArF laser, or a wavelength shorter light than 160 nm (e.g., _{F 2} laser light, light having a wavelength of 12-15Nm) a It is characterized by using.
[0054]
【The invention's effect】
According to the present invention, in forming a resist pattern, the same type of photoresist is used irrespective of the opening of the photomask, and a rectangular shape is obtained in both patterns. This eliminates the need to develop
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a system according to a first embodiment.
FIG. 2 is a view showing a flowchart of a method for forming a resist pattern in the first embodiment;
FIG. 3 is a diagram showing the relationship between the reflectance of exposure light from a resist and the resist film thickness.
FIG. 4 is a diagram showing an example of a resist cross-sectional shape when the resist film thickness is 122 nm, calculated from an optical image.
FIG. 5 is a diagram illustrating an example of a resist cross-sectional shape when the resist film thickness is 99 nm, calculated from an optical image.
FIG. 6 is a diagram showing an example of a layer structure in which a silicon dioxide film, an antireflection film, and a resist layer are formed on a substrate.
FIG. 7 is a diagram showing a resist pattern shape formed by exposure and development using a photomask having a low aperture ratio when the resist film thickness is 122 nm.
FIG. 8 is a diagram showing a resist pattern shape formed by exposure and development using a photomask having a high aperture ratio when the resist film thickness is 122 nm.
FIG. 9 is a diagram showing a resist pattern shape formed by exposure and development using a photomask having a low aperture ratio when the resist film thickness is 99 nm.
FIG. 10 is a view showing a resist pattern shape formed by exposure and development using a photomask having a high aperture ratio when the resist film thickness is 99 nm.
FIG. 11 is a diagram showing resist pattern shapes after exposure and development when the aperture ratio of the photomask is high (left diagram) and when it is low (right diagram).
[Explanation of symbols]
Reference Signs List 11 silicon substrate, 12 silicon dioxide film, 13 antireflection film, 14 resist pattern, 15 silicon substrate, 16 silicon dioxide film, 17 antireflection film, 18 resist pattern, 51 silicon substrate, 52 silicon dioxide film, 53 antireflection film, 54 photoresist film, 61 silicon substrate, 62 silicon dioxide film, 63 antireflection film, 64 resist pattern, 71 silicon substrate, 72 silicon dioxide film, 73 antireflection film, 74 resist pattern, 81 silicon substrate, 82 silicon dioxide film, 83 antireflection film, 84 resist pattern, 91 silicon substrate, 92 silicon dioxide film, 93 antireflection film, 94 resist pattern, 100 resist pattern forming system, 110 layer forming section, 111 coating device, 112 heat treatment device, 120 exposure device , 130 resist pattern forming unit, 131 a heat treatment apparatus, 132 developing apparatus.

Claims (12)

An exposure step of exposing a predetermined region of the photoresist layer using a photomask having an opening,
A layer forming step of forming a photoresist layer to be exposed in the exposure step, by changing the thickness of the layer according to a ratio of the opening portion of the photomask used in the exposure step,
Forming a resist pattern based on the photoresist layer exposed in the exposure step. The photoresist layer, the light reflectance of the light exposed by the exposure step changes depending on the film thickness,
The layer forming step includes forming a photoresist layer having a film thickness with the light reflectance larger than a predetermined value when the ratio of the openings is 50% or more, and forming the photoresist layer with a ratio of the openings smaller than 50%. 2. The method according to claim 1, further comprising forming a photoresist layer having a light reflectance smaller than the predetermined value. A layer forming step of forming a photoresist layer on a film to be processed on the substrate,
An exposure step of exposing a predetermined pattern to a predetermined region of the photoresist layer formed by the layer forming step, using a photomask having a predetermined pattern formed by the opening, having an opening;
A resist pattern forming step of forming a resist pattern based on the photoresist layer on which the predetermined pattern has been exposed by the exposure step,
The layer forming step, in the case of exposing the pattern having a large proportion of the opening portion of the photomask by the exposure step, and in the case of exposing the pattern having a small proportion of the opening portion of the photomask by the exposure step, A method of forming a resist pattern, comprising changing the thickness of the photoresist layer. The method of forming a resist pattern includes the step of forming the photoresist with a thickness of the photoresist at which the light reflectance is maximized based on the dependency of the thickness of the photoresist on the light reflectance from the photoresist at the time of exposure, which is obtained in advance by simulation. A pattern having a large proportion of openings in the mask is exposed by the above-described exposure step, and a pattern having a small proportion of openings in the photomask is exposed by the above-described exposure step at a thickness of the photoresist in which the light reflectance is minimal. 4. The method of forming a resist pattern according to claim 3, wherein: 5. The method according to claim 1, wherein the photoresist layer has a thickness of 300 nm or less. The exposing step is to selectively irradiate a predetermined area of the photoresist layer with an energy ray for exposure,
The method according to claim 1, wherein a KrF laser beam is used as the energy beam. The exposing step is to selectively irradiate a predetermined area of the photoresist layer with an energy ray for exposure,
6. The method according to claim 1, wherein an ArF laser beam is used as the energy beam. The exposing step is to selectively irradiate a predetermined area of the photoresist layer with an energy ray for exposure,
The resist pattern forming method according to claim 1, wherein light having a wavelength shorter than 160 nm is used as the energy ray. A resist pattern forming method according to claim 8, wherein the use of F ₂ laser beam as the energy beam. 9. The method according to claim 8, wherein light having a wavelength of 12 nm or more and 15 nm or less is used as the energy ray. An exposure unit that exposes a predetermined area of the photoresist layer using a photomask having an opening,
According to the proportion of the opening portion of the photomask used in the exposed portion, by changing the thickness of the layer, a layer forming portion to form a photoresist layer to be exposed by the exposed portion,
A resist pattern forming section for forming a resist pattern based on the photoresist layer exposed by the exposure section. In a layer forming apparatus for forming a photoresist layer to be exposed by an exposure apparatus that exposes a predetermined region of the photoresist layer using a photomask having an opening
Forming a photoresist layer to be exposed by the exposure apparatus by changing the thickness of the layer in accordance with the proportion of the opening in the photomask used in the exposure apparatus; apparatus.

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