JP3310202B2 - Method of forming resist pattern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a resist pattern used for fine processing of a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, formation of a fine pattern has become indispensable as the degree of integration of a semiconductor integrated circuit such as an LSI advances. Usually, a fine pattern is formed on a substrate such as a semiconductor wafer by a lithography technique using a resist. With the miniaturization of the pattern, it is important to improve the adhesion between the substrate and the resist film. It has become For example, when the adhesiveness between the substrate and the resist film is not sufficient, peeling of the pattern and flow of the pattern occur during development. In order to avoid such a problem, it is widely practiced to improve the adhesion between the resist pattern and the substrate by performing a process generally called hexamethyldisilazane treatment on the substrate before applying the resist.

However, it has been found that, depending on the substrate on which the resist pattern is to be formed, a new problem occurs in a later step even if the flow of the pattern is not observed during the development of the pattern. For example, when a resist pattern is formed on a chromium mask used for a semiconductor mask or the like, a pattern flow does not occur during development, but the resist pattern is used as an etching mask to selectively pattern the chromium film by wet etching. In this case, the etchant infiltrates the interface between the resist pattern and the substrate. This is due to insufficient adhesion between the resist pattern and the chromium film.

When the etching solution infiltrates from the edge of the resist pattern and side etching occurs in the chromium film pattern, the shape of the chromium film corresponding to the edge of the pattern cannot be formed as designed. In particular,
It becomes difficult to accurately transfer a pattern such as an ultra-fine line or an ultra-fine contact hole formed in the resist pattern to the chromium film. The shape of the chromium film obtained in this way causes a large deviation from the design dimensions,
Since regions having different transmittances are formed, it is necessary to minimize the infiltration of the etching solution into the interface between the resist pattern and the substrate in the semiconductor mask manufacturing process.

[0005]

As described above, in order to improve the adhesion between the resist pattern and the substrate, surface treatment of the substrate is generally performed widely. For example, surface treatment with hexamethyldisilazane has been applied to semiconductor substrates such as silicon wafers, and has succeeded in increasing the adhesion between the resist and the substrate. However, when the substrate to be processed is a chromium substrate, the effect of hexamethyldisilazane is not obtained even if the treatment with hexamethyldisilazane is performed, and it is impossible to prevent the infiltration of the etching solution into the interface between the resist film and the substrate. In addition, the specific surface treatment agent was effective for surface treatment on the chromium substrate, and was effective for improving the adhesion between the resist and the chromium substrate and preventing the penetration of the etchant into the interface. (Japanese Patent Application No. 7-332023). This method greatly improves the penetration of the etching solution, but it causes new problems such as a decrease in throughput due to an increase in the number of steps, and a slight increase in dust (defects) in the surface treatment step. Became.

[0006] It is known that baking a developed resist pattern is effective in increasing the adhesion between the substrate and the resist film. By performing the baking, it is possible to avoid the influence of dust generated when the substrate is subjected to the surface treatment as described above, but in this case, the resist pattern is deformed (flowed).

Accordingly, an object of the present invention is to provide a method of forming a resist pattern which has excellent adhesion to a chromium substrate and can form a pattern having a good sectional shape without any inconvenience.

[0008]

In order to solve the above problems, the present invention provides an acid-catalyzed chemically amplified positive resist containing an alkali-soluble resin, a dissolution inhibitor and an acid generator on a Cr substrate. To form a resist film, a step of irradiating actinic radiation to a predetermined region of the resist film to perform pattern exposure to generate an acid in an exposed portion, and a step of forming the resist film after the pattern exposure Heat-treating to promote the acid-catalyzed reaction; and developing the resist film after the heat treatment using a developing solution to selectively dissolve and remove exposed portions of the resist film to form a resist pattern. Forming and increasing the glass transition temperature of the resist by removing all protective groups of the dissolution inhibitor in the pattern while maintaining the shape of the resist pattern after the development processing. And degree, to a method of forming a resist pattern and a step of heat treating the resist pattern at a temperature above the glass transition temperature of the elevated registration.

Hereinafter, the present invention will be described in more detail. The chemically amplified resist used in the method for forming a resist pattern of the present invention generates an acid by irradiation with actinic radiation such as visible light, ultraviolet light, or an electron beam or X-ray, and then appropriately performs a heat treatment. There is no particular limitation as long as it is a chemically amplified positive resist in which an acid-catalyzed reaction occurs.

The positive chemically amplified resist is composed of, for example, an alkali-soluble resin, a dissolution inhibitor, and a compound capable of generating an acid upon irradiation with actinic radiation (hereinafter referred to as an acid generator).

As the alkali-soluble resin, for example,
Novolak resins, polyhydroxystyrene, and the like. Examples of the dissolution inhibitor include compounds in which some or all of the hydroxyl groups of polyhydroxystyrene are substituted with a tertiary butoxycarbonyl group, a tertiary butoxycarbonylmethyl group, and a tetrahydropyranyl ether group, and bisphenol A and cresolphthalein. One or two of the hydroxyl groups is a tertiary butoxycarbonyl group, a tertiary butoxycarbonylmethyl group,
And a compound substituted with a tetrahydropyranyl ether group.

Examples of the acid generator include onium salts such as triphenylsulfonium trifluoromethanesulfonate and diphenyliodonium trifluoromethanesulfonate; sulfonyl compounds such as bisphenylsulfonylmethane and phenylsulfonylacetonitrile; orthonitrobenzyl paratoluenesulfonate; And the like.

By dissolving the above-mentioned components in an organic solvent at a predetermined ratio, a solution of an acid-catalyzed chemically amplified positive resist used in the present invention can be obtained. In addition, the compounding amount of the alkali-soluble resin is usually 50 to 90 in the total solid content.
wt%, and the amount of the dissolution inhibitor is 10 to 50 w.
t%, and the compounding amount of the acid generator is 0.1 to 10.0 wt.
%.

Examples of usable organic solvents include ketone solvents such as cyclohexanone, acetone, methyl ethyl ketone, methyl amyl ketone and methyl isobutyl ketone; cellosolve solvents such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate and isobutyl cellosolve acetate; Ester solvents such as ethyl acetate, butyl acetate, isoamyl acetate, and γ-butyrolactone are exemplified.

The obtained resist solution is applied on a Cr substrate by, for example, spin coating or dipping, and then dried to form a resist film. The heating temperature and time can be appropriately selected according to the type of the resist, the organic solvent used, and the like.
It is preferable to perform heating at about 130 ° C. for about 1 to 10 minutes.

Subsequently, pattern exposure is performed on the resist film. As an exposure light source, deep UV light of KrF or ArF excimer laser, X-ray, electron beam, etc. can be used. In photomask fabrication, it is common to perform electron beam exposure on a resist film on a Cr mask substrate. It is a target.

Thereafter, the resist film is subjected to a heat treatment (baking, PEB) by using a hot plate or an oven or by irradiating ultraviolet rays. The temperature of PEB is
It can be appropriately selected according to the type of the resist, and for example, is preferably in the range of about 50 to 130 ° C.

Next, the resist film is developed by an immersion method, a spray method or the like. The developer used here can be appropriately selected according to each resist. For example, an organic alkali aqueous solution such as a tetramethylammonium hydroxide aqueous solution and a choline aqueous solution; and an inorganic alkali aqueous solution such as a potassium hydroxide aqueous solution and a sodium hydroxide aqueous solution are exemplified. In these alkaline aqueous solutions,
Alcohol or a surfactant may be added.

The developed substrate and resist film are appropriately rinsed with water or the like, and then dried to obtain a desired pattern. In the method of forming a resist pattern according to the present invention, the protective groups (such as tertiary butoxycarbonyl group, tertiary butoxycarbonylmethyl group, and tetrahydropyranyl ether group) of the dissolution inhibitor in the resist pattern after development are all decomposed. And raise the glass transition temperature (T _g ) of the resist.

In decomposing the dissolution inhibiting group, for example, a method of subjecting a Cr substrate on which a resist pattern is formed to a heat treatment using a hot plate or an oven while maintaining the pattern shape while gradually increasing the temperature is used. No.
Conditions for the heat treatment can be appropriately selected according to the type of the resist (the type of the dissolution inhibitor). However, the heating temperature must always be higher than the decomposition temperature of the resist, and specifically, is preferably in a temperature range represented by the following equation.

T ≦ T _g + 20 ° C. (1) (where T _g is the glass transition temperature of the resist,
Is the heating temperature. The term "decomposition temperature of the resist" used herein means a temperature at which the dissolution inhibiting group of the resist decomposes.

As a method of raising the temperature, for example, 100 to 1
The heating temperature can be increased in a so-called slope shape in a range of 50 ° C. for 10 to 60 minutes. It should be noted that the rapid temperature rise may cause the flow of the pattern, so that it is necessary to decompose the inhibitory group and effectively raise the temperature while maintaining the pattern shape.

Also, a so-called stepwise temperature rise in which the heating temperature is gradually raised while maintaining the temperature at a predetermined temperature for about 1 to 10 minutes may be employed. Also in this case, it is preferable to increase the temperature in as small a temperature increase width as possible, for example, in steps of about 1 to 5 ° C.

The step of removing all the protective groups of the dissolution inhibitor comprises:
The heat treatment is not limited to the above-described heat treatment, and may be performed by a method described below. Specifically, after irradiating the entire resist pattern with ionizing radiation such as deep UV light, X-rays, and electron beams, PEB is performed to remove all the protective groups of the dissolution inhibitor. For example, when deep UV light is used, 1
After irradiating with an exposure amount of 0 to 200 mJ / cm ² ,
By performing PEB at a temperature of 120 ° C. for 5 to 30 minutes, all the protecting groups of the dissolution inhibitor can be removed.

The amount of exposure to ionizing radiation and the conditions for PEB can be appropriately determined according to the type of the dissolution inhibiting group of the resist used and the type of acid generator. The resist pattern from which all the protective groups of the dissolution inhibitor have been removed is subjected to a heat treatment using a hot plate or an oven. Since all the dissolution inhibiting groups have been removed in the above-described process, the heat treatment here does not cause decomposition of the inhibiting groups (the generation of voids due to gasification) which causes the infiltration of the etching solution. Also, the glass transition temperature does not fluctuate. The heat treatment is preferably performed at a temperature higher than the glass transition temperature of the resist raised in the above-described step, for example, at 140 to 180 ° C. for 10 to 60 minutes. The heating temperature and time vary depending on the type of the dissolution inhibiting group in the resist, etc., but in order to avoid deformation of the resist pattern, the heating temperature range is a temperature not exceeding 10 ° C. from the final glass transition temperature, Is desired to be a temperature higher than the final glass transition temperature by 5 ° C. or less.

In the method of forming a resist pattern according to the present invention, after the T _g is increased by removing all the protective groups of the dissolution inhibitor in the developed resist pattern, the resist pattern is further formed at a temperature higher than the T _g. Since the heat treatment is performed, the adhesion between the resist pattern and the chromium substrate can be significantly improved. Moreover, in the step of heating the resist pattern, care is taken to maintain the shape of the pattern, so that deformation (flow) of the pattern can be avoided.

The present inventors have conducted intensive studies on baking of a resist pattern after development. As a result, it has been found that baking at a temperature excessively higher than the glass transition temperature (T _g ) of the resist causes deformation of the resist pattern. Furthermore, the optimum baking temperature to increase the adhesion between the resist pattern and the substrate was found to be a temperature higher than the T _g. By baking the resist pattern after development at a temperature higher than T _g , Brownian motion of the polymer main chain occurs, and voids and stresses in the polymer which cause a decrease in adhesion are considered to be released. .

Since the chemically amplified positive resist contains a dissolution inhibitor for controlling the dissolution rate, its glass transition temperature is relatively lower than that of the compound before the protective group is introduced. . This is because the protecting group of the dissolution inhibitor is
This is because it is generally bulkier than the unprotected group.

It has been found that what further complicates the problem is the following phenomenon. That is, the temperature of thermal decomposition (deprotection reaction) of a typical protective group (tertiary butoxycarbonyl group, pyranyl ether group) or the like in the dissolution inhibitor of the chemically amplified positive resist is near the glass transition temperature. By carrying out baking above the glass transition temperature, these protecting groups begin to come off. According to the protection group of dissolution inhibitor deviates Thus, under high polarity groups (e.g., hydroxyl, etc.) so begin to appear, T _g of the resist continues to rise, T _g when all of the protecting groups off Is a constant value. Without causing deformation of the resist pattern, and a sufficiently enhance the adhesion between the substrate and the resist pattern must be baked at very high temperatures the T _g which continues to rise, moreover, the baking temperature of a given Limited to range.

Therefore, the following problems have occurred in the general single temperature baking process. For example, if you set the baking temperature to be lower in order to suppress the flow of the resist pattern, the protective group of dissolution inhibitor is T _g is increased as decomposed by the heat reaction, T _g is the baking temperature at a certain point Beyond. As described above, in order to increase the adhesion between the resist pattern and the substrate, it is necessary to perform baking at a temperature higher than T _g. Thus, if T _g exceeds the baking temperature, the effect of baking will be lost. No longer available. On the other hand, when dissolution inhibiting group makes a baked at final T _g higher temperatures to be determined after completely off completely is also another problem arises. That is, the temperature for a much higher temperature than the resist a T _g in the baking initial stage, the flow of the resin pattern size going fluctuates greatly during heating. As a result, the deformed resist pattern comes into close contact with the substrate.

In the present invention, attention is paid to the T _g of the resist, and the resist pattern after development is treated so as to remove all the protective groups of the dissolution inhibitor which causes the T _g to increase. It has become possible to avoid all conventional problems.

The resist pattern formed by the method of the present invention has excellent adhesion to a Cr substrate, and its shape is not damaged at all. For this reason, using the obtained resist pattern as an etching mask, the Cr substrate is immersed in, for example, an acidic etching solution and wet-etched, whereby the resist pattern is accurately transferred to a member to be etched (Cr film). be able to.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention. Example 1 First, 58 wt% of a resin in which hydroxyl groups of polyvinyl phenol having a molecular weight (Mw = 30000) were protected by 30% tert-butyl acetate group, and a molecular weight (Mw = 100)
35) by weight of polyvinyl phenol (00) and triphenylsulfonium triflate 7 as an acid generator
wt% was dissolved in methyl 3-methoxypropionate as a solvent to obtain a resist solution. The resist is irradiated with deep UV light, X-rays or high-energy electron beams to generate an acid, which decomposes a tertiary butyl acetate group, which is a protective group of the dissolution inhibitor, to form an exposed portion. Since it exhibits alkali solubility, it is a positive chemically amplified resist in which a pattern is formed by selectively dissolving and removing exposed portions by developing with an aqueous alkali solution.

This resist solution was applied on a Cr substrate used as a photomask with a thickness of 0.5 μm by a spinner and dried by baking at 100 ° C. for 5 minutes to form a resist film. Thereafter, a high-energy electron beam having a beam diameter of 0.25 μm (acceleration voltage 15 KeV) was
By scanning under the condition of μC / cm ² , a line and space pattern and a contact hole were drawn on the resist film.

Subsequently, heating at 60 ° C. for 5 minutes after exposure (PE
After performing B), development was performed with an aqueous solution of tetramethylammonium hydroxide (TMAH) (2.38 wt%) to form a resist pattern.

The obtained resist pattern was treated at 130 ° C. for 5 minutes, at 135 ° C. for 5 minutes, at 140 ° C. for 5 minutes, and at 145 ° C.
5 minutes at 150 ° C., 5 minutes at 150 ° C., and 5 minutes at 155 ° C.
Baking was performed at 160 ° C. for 15 minutes. (Example 2) A resist pattern was formed in the same procedure as in Example 1 described above, and the temperature was increased from 130 ° C to 160 ° C at a rate of 1 ° C / min, followed by baking at 160 ° C for 15 minutes. The temperature rise in this embodiment can be called a slope-like temperature rise. (Comparative Example 1) A resist pattern was formed in the same procedure as in Example 1 described above, and baked at 160 ° C for 45 minutes. (Comparative Example 2) A resist pattern was formed in the same procedure as in Example 1 described above, and baked at 140 ° C for 45 minutes. (Etching of Chromium Film) The chromium substrate on which the resist pattern was formed in Examples 1 and 2 and Comparative Examples 1 and 2 was
The resist pattern was transferred to a chromium film by selectively etching with a cerium ammonium nitrate etchant to obtain a sample.

For each sample, the interface between the resist pattern and the chromium film was observed with a scanning electron microscope, and the penetration distance of the etchant from the pattern edge was measured.
Table 1 below shows the obtained results together with the cross-sectional shape of each pattern.
Summarized in

[0038]

[Table 1]

As shown in Table 1 above, the case where the baking treatment was performed through the stepwise heating process (Example 1) and the case where the baking treatment was performed after the slope heating process (Example 2) In any of the cases (1) and (2), no change in the shape of the resist pattern was observed at all, and the infiltration of the etching solution into the interface between the resist pattern and the substrate was suppressed to 0.1 μm.

On the other hand, in Comparative Example 1 which was baked at 160 ° C., although the infiltration of the etching solution into the interface was suppressed, the resist pattern was greatly deformed, so that the chromium film was formed with the dimensions as designed. The pattern could not be transferred. This can be explained by the mechanism that the glass transition temperature of the used resist increases during baking.

The initial glass transition temperature (T _g ) of the resist used in Examples 1 and 2 and Comparative Examples 1 and 2 was about 120 ° C., and all the protective groups of the dissolution inhibitor were removed. The latter T _g was about 155 ° C. That is, 16
The one-step baking at 0 ° C. results in baking at a final T _g or more, which has an annealing effect, improves the adhesion between the resist pattern and the substrate, and prevents the infiltration of the etchant into the interface. Was. However, the temperature of 160 ° C. is about 40 ° C. higher than the initial T _{g of the} resist, so that the resist pattern flows during heating at this temperature. Therefore, the resist pattern comes into close contact with the substrate after a large change in the pattern size of the resist, and the chromium film cannot be etched accurately with a resist pattern having such a changed dimension.

On the other hand, in Comparative Example 2 where the resist pattern was baked at 140 ° C., no deformation of the resist pattern was observed, but the adhesion between the substrate and the resist pattern was poor, so that the etching solution penetrated, and the pattern transfer to the substrate was difficult. It was impossible. Since the protective group of the dissolution inhibitor breaks down during the baking treatment at 140 ° C., the glass transition temperature of the resist, which was initially 120 ° C., eventually rises to near 155 ° C. Therefore, 140 ° C. below the final T _g
In this case, the annealing effect of baking above T _g was not exhibited. Example 3 First, a resin in which polyvinylphenol hydroxyl groups having a molecular weight (Mw = 20,000) were protected with 25% tertiarybutoxycarbonyl group at 60 wt% and a molecular weight (Mw = 20,000)
8000) and 3 wt% of triphenylsulfonium triflate as an acid generator were dissolved in methyl 3-methoxypropionate as a solvent to obtain a resist solution. The resist is irradiated with deep UV light, X-rays, or high-energy electron beams to generate an acid, which decomposes a tertiary butoxycarbonyl group, which is a protective group of a dissolution inhibitor, to form an exposed portion. Is a positive chemically amplified resist in which a pattern is formed by selectively dissolving and removing exposed portions by developing with an aqueous alkali solution because of exhibiting alkali solubility.

This resist solution was applied on a Cr substrate used as a photomask with a thickness of 0.5 μm by a spinner and dried by baking at 100 ° C. for 5 minutes to form a resist film. Thereafter, a high-energy electron beam having a beam diameter of 0.25 μm (acceleration voltage 15 KeV) was
By scanning under the condition of μC / cm ² , a line-and-space pattern and contact holes were drawn on the resist film.

Subsequently, heating at 80 ° C. for 5 minutes after exposure (PE
After performing B), development was performed with an aqueous solution of tetramethylammonium hydroxide (TMAH) (2.38 wt%) to form a resist pattern.

The obtained resist pattern was heated at a rate of 1 ° C.
/ Min at 120 ° C / min.
Bake at 0 ° C. for 15 minutes. (Example 4) A resist pattern was formed in the same procedure as in Example 3 described above, and the entire surface of the pattern was irradiated with about 100 mJ / cm ² using a mercury lamp, and then subjected to PEB at 80 ° C for 30 minutes. The resist pattern after PEB was further baked at 170 ° C. for 15 minutes. (Comparative Example 3) A resist pattern was formed in the same procedure as in Example 3 described above, and baked at 170 ° C for 60 minutes. (Etching of Chromium Film) Examples 3, 4 and Comparative Example 3
The resist pattern was formed on the chromium film by selectively etching the chromium substrate on which the resist pattern was formed by using a cerium ammonium nitrate etchant to obtain a sample.

With respect to each sample, the interface between the resist pattern and the chromium film was observed with a scanning electron microscope, and the penetration distance of the etching solution from the pattern edge was measured.
The obtained results are summarized in Table 2 below together with the pattern shapes.

[0047]

[Table 2]

As shown in Table 2 above, when the baking treatment was performed through a slope-like temperature raising process (Example 3), the sample was subjected to deep UV light irradiation, and then subjected to the PEB step (Example 4). In each of the cases (1) and (2), no change in the shape of the resist pattern was observed, and the penetration of the etching solution into the interface between the resist pattern and the substrate was 0.1 μm.
It is suppressed to.

On the other hand, in Comparative Example 3 baked at 170 ° C., although the infiltration of the etching solution into the interface was suppressed, the resist pattern was greatly deformed, so that the chromium film was formed with the dimensions as designed. The pattern could not be transferred. This can be explained by the mechanism that the glass transition temperature of the resist rises during baking, as in the case of Examples 1 and 2 and Comparative Examples 1 and 2.

The initial glass transition temperature (T _g ) of the resist used in Examples 3 and 4 and Comparative Example 3 was about 120.
° C, and the T _g was about 160 ° C after all the protective groups of the dissolution inhibitor had been removed. That is, there is annealing effect since the final T _g or baking in one step baking 170 ° C., can be prevented only write immersion in the etching solution into the interface is improved adhesion between the resist pattern and the substrate did it. However, since the temperature of 170 ° C. is about 50 ° C. higher than the initial T _g of the resist, the flow of the resist pattern occurs during heating at this temperature. Therefore, the resist pattern comes into close contact with the substrate after the pattern size of the resist has largely changed, and the chromium film cannot be etched accurately with the resist pattern having such changed dimensions.

On the other hand, in Example 3, a slope-like heat treatment was performed, and in Example 4, deep UV light irradiation was performed.
The dissolution inhibiting groups in the resist pattern are all removed by the PEB process. In any of the examples, the heating was not performed at a temperature significantly higher than T _g until all the dissolution inhibiting groups were removed, so that the decomposition reaction of the dissolution inhibiting groups did not occur at all without causing the resist pattern to flow. The glass transition temperature rises sufficiently to increase. After all the dissolution inhibiting groups were removed, T _g reached a constant value of 160 ° C.
The annealing effect was obtained by baking at 70 ° C.

[0052] That is, through the sloped baking or irradiation -PEB deep UV light step, after increasing a T _g by removing all dissolution inhibiting group in the resist, further baked at a temperature above its T _g By doing so, it was possible to form a resist pattern having excellent adhesion to the substrate without causing deformation of the resist pattern.

[0053]

As described in detail above, according to the present invention,
It is possible to form a resist pattern having a good shape, in which the adhesion to a substrate, particularly a chrome mask substrate for producing a reticle, is significantly improved. When the chromium substrate is selectively patterned by wet etching using the resist pattern formed by the method of the present invention as an etching mask, the infiltration of the etching solution into the interface between the resist pattern and the chromium film is suppressed. You. Moreover, since the resist pattern formed by the method of the present invention does not undergo deformation, the resist pattern can be accurately transferred to the chromium film as designed.

Therefore, such a method for forming a resist pattern is extremely effective in producing a reticle in a manufacturing process of a semiconductor device or the like, and its industrial value is enormous.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Makoto Nakase, Inventor Makoto Nakamukai, Kawasaki City, Kanagawa Prefecture 1, Komukai Toshiba Town, Toshiba R & D Center Co., Ltd. (56) References JP-A-6-214402 (JP, A) JP-A-6-69118 (JP, A) JP-A-58-207044 (JP, A) JP-A-62-113141 (JP, A) JP-A-5-267154 (JP, A) JP-A-6-186755 (JP, A) JP, A) JP-A-10-20510 (JP, A) JP-A-5-152716 (JP, A) JP-A-63-220523 (JP, A) JP-A-60-117627 (JP, A) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) H01L 21/027 G03F 7/40 501

Claims (2)

(57) [Claims] 1. A step of applying a chemically amplified positive resist of an acid catalyst type containing an alkali-soluble resin, a dissolution inhibitor and an acid generator on a Cr substrate to form a resist film; A step of generating an acid in an exposed portion by irradiating a predetermined area with actinic radiation and performing pattern exposure, and a step of subjecting the resist film after the pattern exposure to a heat treatment to advance a catalytic reaction by the acid, Developing the resist film after the heat treatment using a developing solution and selectively dissolving and removing exposed portions of the resist film to form a resist pattern; and maintaining the shape of the resist pattern after the development treatment. Increasing the glass transition temperature of the resist by removing all protective groups of the dissolution inhibitor in the pattern while removing the glass transition temperature of the resist. A resist pattern forming method characterized by at temperatures and a step of heating the resist pattern. 2. The step of removing all protective groups of the dissolution inhibitor in the resist pattern is carried out by heating the resist pattern at a temperature higher than its decomposition temperature. 2. The method for forming a resist pattern according to claim 1, wherein the range is represented by 1). T ≦ T _g + 20 ° C. (1) (where T _g is the glass transition temperature of the resist,
Is the heating temperature. )