KR0171665B1 - Positive resist composition - Google Patents

Abstract

Improved chemically amplified positive resist compositions for radiation, in particular ultraviolet light, deep ultraviolet light, excimer laser beams, X-rays, electron beams are disclosed.

The composition comprises a compound (B) and an organic carboxylic acid compound (C) which generate an acid upon irradiation with a resin component (A) which has increased solubility in an aqueous alkali solution due to the action of an acid, wherein the resin component (A) (a) polyhydroxystyrene in which about 10-60 mole% of the hydroxyl groups are substituted with the residue of general formula (I); And

Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a methyl group or an ethyl group, and R ³ means a lower alkyl group having 1 to 4 carbon atoms.

(b) polyhydroxy styrene in which about 10-60 mole percent of the hydroxyl groups are motivated by tert-butoxycarbonyloxy groups; It is a mixture consisting of.

The composition has a high sensitivity, high resolution, high flame resistance, good width characteristics at depth of focus, good post-exposure storage stability, good storage stability as a resist solution, and a resist pattern having a good profile without dependence on the substrate to which it is applied. Grant.

This composition can be advantageously used for micropattern formation in ultra-LSI production.

Description

Method of forming patterned resist layer on substrate

The present invention relates to a method of forming a patterned resist layer on a substrate, and more particularly has high sensitivity, high resolution, high heat resistance, good width characteristics of the depth of focus and excellent post-exposure stability, good storage stability as a resist solution, Responsive to radiation such as ultraviolet rays, far ultraviolet rays, excimer laser beams such as KrF lasers and ArF lasers, x-rays, electron beams, etc., which can form resist patterns with excellent profile shapes on the substrates without depending on the substrates applied. It is about a method.

Conventional semiconductor devices, such as IC and LSI, have been fabricated by repeating a series of processes including photolithography (photolithography), etching, impurity diffusion and microwiring using a photoresist composition.

That is, in the photolithography process, a thin film of the photoresist composition is formed on a silicon substrate by, for example, spin coating, and the resultant is activated by ultraviolet rays through a mask pattern on which a semiconductor device pattern is drawn. After exposure to light, it is developed to obtain a resist pattern, which is then etched into the silicon substrate having the resist pattern on its surface serving as a protective film. As a preferred photoresist composition used for the photolithography, a resolution of a sub-micron region (1 µm or less) or a half-micron region (0.5 µm or less) is required. Positive photoresist compositions based on compounds containing alkali-soluble novolac resins and quinonediazido groups using ultraviolet rays such as g-rays (436 nm) and I-rays (365 nm) for exposure are known.

Recently, as high integration of semiconductor devices is rapidly required, processing precision of ultra-fine patterns of quarter micron region (0.25 m or less) is required for mass production of ultra-LSI and the like.

However, conventional amphoteric photoresist compositions comprising a compound containing an alkali soluble novolak resin and a quinonediazido group as the base component cannot provide the ultrafine patterning process as described above.

Accordingly, development of resists using shorter wavelengths (200-300 nm) of deep-UV rays, excimer laser beams such as KrF lasers and ArF lasers, electron beams, and X-rays has been required.

Today high resolution, chemically amplified resists with high sensitivity, using catalysts and chain reactions of acids produced by radiation exposure, quantum yields of one or more, and high sensitivity are attracting attention and intensively. Has been studied.

As an example of such a chemically amplified positive resist, a resist containing a resin component derived by substituting a hydroxyl group of polyhydroxystyrene with a tert-butoxycarbonyloxy group or the like and an onium salt as an acid generator is known. (US Pat. No. 4,491,628).

However, the known chemically amplified positive resists are not satisfied with the width characteristic in focus depth in resolution and depth of focus, and the upper part of the pattern becomes wider in the cross-sectional profile shape of the pattern made of resist. Since this causes so-called bridging problems (hereinafter, this phenomenon is referred to as 'decrease in storage stability' of the positive resist, there is a problem in actual use. To describe the problem in more detail, when the chemically amplified positive resist coated on a substrate is exposed, left for a while and then developed to form a pattern, the pattern is generated by exposure while the exposed resist film is left unattended. The acid is deactivated, resulting in poor profile shape. When such bridging occurs, the required fine line formation pattern cannot be obtained, which is a serious problem in manufacturing a semiconductor device.

In order to improve such storage stability problems after exposure, a method has been proposed to prevent the deactivation of acid generated by exposure by providing a top coating layer on the resist layer.

However, this method not only increases the process steps but also reduces the output, which leads to an increase in production costs. For this reason, this method is not appropriate. Therefore, there is a strong demand for developing a resist having excellent storage stability after exposure without providing a top coating layer.

The problem with chemically-amplified positive resists as described above is that their properties depend on the substrate to which they are applied, and some of them have insulating films such as silicon nitride (SiN), boron-in-silicate glass (BPSG), etc. When applied on a coated substrate or a substrate coated with titanium nitride (TiN), there is a case where the profile of the resist pattern expands below the substrate (hereinafter, such a problem is referred to as 'substrate dependency'). The acid generated by the exposure is inactivated by the action of amines remaining around the substrate in the film forming step, which is believed to cause the profile shape to form a resist pattern that has expanded to the bottom of the substrate.

Furthermore, when such a resist is coated on a substrate coated with a metal film such as an aluminum-silicon-copper (Al-Si-Cu) film and a tungsten (W) film, the formed resist film is formed of standing waves. Under influence, the cross-sectional profile of the resist pattern is corrugated.

In order to solve such a problem of substrate dependence and standing waves, a method of providing an anti-reflection coating layer between the substrate and the resist layer has been proposed.

However, this method also has a problem that not only the output decreases due to the increase of the process step but also the production cost increases. For this reason, this method is also not appropriate. Therefore, there is a need for a method capable of providing a pattern having an excellent profile without providing an antireflection coating layer and having no dependence of a substrate to be applied and not affected by standing waves.

In addition to the problems described above, the conventional resist composition has another problem. That is, when the resist composition is prepared as a solution, there is a poor storage stability problem in which the solution generates a solid material while the solution is stored. There is also a need for a resist composition that can provide a resist solution that has good storage stability and does not generate any solid material during storage.

The present inventors have long researched to develop a method of forming a patterned resist layer on a substrate that can solve the above-mentioned problems. As a result, the present invention is a resin component having an increased solubility in aqueous alkali solution due to the action of acid. By using two different polyhydroxystyrenes each substituted to some extent with two different kinds of substituents, and also an organic carboxylic acid, high sensitivity, high resolution, high heat resistance, good width characteristics at depth of focus and good post-exposure storage Ultraviolet, far-ultraviolet and excimer laser beams (KrF laser, ArF laser, etc.), which have stability, have excellent storage stability when produced as a resist solution, and provide a resist pattern having a good profile on the substrate without depending on the applied substrate. And X-rays, electron beams and other radiation-sensitive methods have been found. Based on these findings, the present invention has been completed. Accordingly, an object of the present invention is to transmit radiation, especially deep-UV rays and excimer laser beams (KrF laser, ArF laser, etc.), and have high heat resistance with high sensitivity and high resolution, and have a width characteristic at a depth of focus. In addition, the present invention provides a method capable of forming a resist pattern having a good profile which is not only excellent but also has good storage stability after exposure and excellent storage stability when manufactured with a resist solution and does not depend on a substrate to be applied.

The method according to the present invention has high sensitivity, high resolution in the quarter micron or lower region, high heat resistance, good width characteristics at depth of focus and good post exposure stability. In addition, according to the method of the present invention, it is possible to form a resist pattern having a good profile without depending on the substrate to be applied.

Therefore, the method of the present invention is satisfactory for the manufacturing process of a semiconductor device which requires a resolution in the quarter micron region.

In addition, the present invention has better resist characteristics as compared with the conventional method comprising a resin component in which a hydroxyl group is substituted with a tert-butoxycarbonyloxy group and an acid generator.

Therefore, the present invention can reduce the manufacturing cost of the semiconductor device by coating the composition on the substrate in a single layer without using the top coating layer or the anti-reflective coating layer to increase the manufacturing step of the device.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The method according to the invention

(i) a resin component (a) having an increased solubility in an aqueous alkali solution due to the action of an acid; a compound (b) and an organic carboxylic acid compound (c) which generate an acid upon irradiation, wherein the resin component (a)

(a) polyhydroxystyrene in which 10-60 mol% of the hydroxyl groups are substituted with the residues of the general formula (I)

(Wherein R ¹ is a hydrogen atom or a methyl group, R ³ is a lower alkyl group having 1-4 carbon atoms; and (b) 10-60 mole% of the hydroxyl group is substituted with tert-butoxycarbonyloxyl group Coating the surface of the substrate with a positive resist composition formed by mixing polyhydroxystyrene;

(ii) selectively exposing the resist layer to actinic light;

(iii) heating the exposed resist layer; And

(iv) developing the resultant resist layer to form a desired pattern using a developing solution.

As mentioned above, the positive resist composition of the present invention comprises not only component (a) as a mixture of components (a) and (b) but also an organic carboxylic acid compound.

Accordingly, the composition of the present invention is a polyhydroxystyrene in which a hydroxyl group is partially substituted with an alkoxyalkoxy group of the general formula (I) as component (A), or a polyhydride in which a hydroxyl group is partially substituted with a tert-butoxycarbonyloxy group. The heat resistance or resolution degradation of the resist pattern, which can be caused in the resist composition containing oxystyrene as a single component, never occurs.

Furthermore, the composition of the present invention has high sensitivity, high resolution, high heat resistance, good width characteristic at depth of focus and good post-exposure storage stability, good storage stability when prepared as a resist solution, and good for substrate without dependence on the applied substrate. It is to provide a resist pattern having a profile.

In the mixture (A) which is a resin component, component (a) is 30-90% by weight, and component (b) is in the range of 10-70% by weight. Preferably component (a) is 50-80% by weight, component (b) is preferably included in the range of 20-50% by weight.

Specific examples of the residue represented by the general formula (I) in the component (a) include 1-methoxyethoxy group, 1-ethoxyethoxy group, 1-n-propoxy-ethoxy group and 1-iso-propoxy To oxy group, 1-n-butoxyethoxy group, 1-iso-propoxyethoxy group, 1-n-butoxyethoxy group, iso-butoxyethoxy group, 1- (1,1-dimethyl Methoxy) -1-methylethoxy group, 1-methoxy-1-methylethoxy group, 1-ethoxy-1-methyl-ethoxy group, 1-n-propoxy-1-methylethoxy group, 1- Isobutoxy-1-methylethoxy group, 1-methoxy-n-propoxy group, and 1-ethoxy-n-propoxy group.

Among them, 1-ethoxyethoxy group and 1-methoxy-n-propoxy group are particularly preferable in that the sensitivity and resolution of the composition are well matched and improved.

According to the method of the present invention, the resin component with respect to the alkaline aqueous solution on the exposed part of the film is obtained by decomposing the tert-butoxycarbonyloxy group and the residue of the formula (I) in which the acid produced from the acid generator is produced from the acid generator. ) Solubility and dissolution prevention ability on the unexposed areas of the film are well balanced, resulting in improved sensitivity, high resolution and high heat resistance as well as width characteristics at depth of focus.

In the component (a), for example, a hydroxyl group is substituted by a known substitution reaction such as unsubstituted polyhydroxystyrene and 1-chloro-1-ethoxy-ethane or 1-chloro-1-methoxy propane. Polyhydroxystyrene partially substituted with the residue of (I).

The degree of substitution of the hydroxyl groups with residues here is about 10-60 mole%, preferably 20-50 mole%. When the substitution degree is less than 10 mol%, the positive resist composition containing the resin component cannot provide a resist pattern having a good profile. On the other hand, if it exceeds 60 mol%, the sensitivity of the composition is lowered. Therefore, it is preferable that substitution degree does not deviate from the said range. In actual use of the composition, the degree of substitution is preferably 20-50 mol%. The component (b) is a polyhydride in which a hydroxyl group is partially substituted with a tert-butoxycarbonyloxy group by, for example, a known substitution reaction such as unsubstituted polyhydroxystyrene and di-tert-butyldicarbonate. Roxystyrene. The degree of substitution in which the hydroxyl group is substituted with tert-butoxycarbonyloxy group is 10-60 mol%, preferably 20-50 mol%.

When the substitution degree is less than 10 mol%, the positive resist composition containing the resin component does not give a resist pattern having a good profile. On the other hand, if it exceeds 60 mol%, the sensitivity of the composition is lowered. Therefore, it is better not to deviate from the said range. In actual use of the composition, the degree of substitution is preferably 20-40 mol%.

The weight average molecular weight of each resin component is in the range of about 3,000-30,000, preferably 8,000-22,000, based on polystyrene as measured by gel permeation chromatography (GPC). When the weight average molecular weight is less than the above range, the coatability of the resin-containing composition is poor. On the other hand, when it exceeds the said range, the solubility of resin in aqueous alkali solution falls.

In addition, the resin component of the present invention has a molecular weight distribution (Mw / Mn) of 3-5, which is the ratio between the weight average molecular weight and the number average molecular weight.

The resin component (a) is a mixture containing two kinds of polyhydroxystyrene in which the hydroxyl group is substituted with the alkoxyalkoxy group of the formula (I) and the tert-butoxycarbonyloxy group, respectively, It is not specifically limited, A mixture in which a hydroxyl group contains two or more types of polyhydroxystyrene each substituted by well-known acid-releasing substituents, such as a tetrahydropyranyloxy group, a tetrahydrofuranyloxy group, a trimethylsilyloxy group, etc. Can be.

The acid generator used in the composition of the present invention can be used conventionally known as an acid generator, but is not limited thereto. Specific examples include (i) bis (p-toluenesulfonyl) diazomethane, methylsulfonyl-p-toluenesulfonyldiazomethane, 1-cyclohexylsulfonyl-1- (1,1-dimethylethylsulfonyl ) Diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, bis (1-methylethylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (2,4- Dimethylphenylsulfonyl) diazomethane, bis (4-ethylphenylsulfonyl) diazomethane, bis (3-methylphenylsulfonyl) diazomethane, bis (4-chlorophenylsulfonyl) diazomethane, bis (4 Bissulfonyl diazomethanes such as -fluorophenylsulfonyl) diazomethane, bis (4-methoxyphenylsulfonyl) diazomethane and bis (4-tert-butylphenylsulfonyl) diazomethane;

(ii) 2-methyl-2- (p-toluenesulfonyl) propiophenone, 2- (cyclohexylcarbonyl) 2- (p-toluenesulfonyl) propane, 2-methanesulfonyl-2-methyl- ( Sulfonylcarbonyl alkanes such as 4-methylthio) pyopiophenone and 2,4-dimethyl-2- (p-toluenesulfonyl) pentan-3-one;

(iii) 1-p-toluenesulfonyl-1-cyclohexylcarbonyldiazomethane, 1-diazo-1-methylsulfonyl-4-phenyl-2-butanone, 1-cyclohexylsulfonyl-1- Cyclohexyl-carbonyldiazomethane, 1-diazo-1-cyclohexylsulfonyl-3,3-dimethyl-2-butanone, 1-diazo-1- (1,1-dimethylethylsulfonyl)- 3,3-dimethyl-2-butanone, 1-acetyl-1- (1-methylethylsulfonyl) diazomethane, 1-diazo-1- (p-toluenesulfonyl) -3,3-dimethyl- 2-butanone, 1-diazo-1-benzenesulfonyl-3, 3-dimethyl-2-butanone, 1-diazo-1- (p-toluenesulfonyl) -3-methyl-2-butanone , 2-diazo-2- (p-toluenesulfonyl) cyclohexyl acetate, 2-diazo-2- (benzenesulfonyl) tert-butyl acetate, 2-diazo-2-methane sulfonyl isopropyl acetate, Sulfonylcarbonyldiazomethanes such as 2-diazo-2-benzenesulfonyl cyclohexyl acetate, and 2-diazo-2- (p-toluenesulfonyl) tert-butyl acetate;

(iv) nitrobenzyl derivatives such as 2-nitrobenzyl-p-toluenesulfonate, 2,6-dinitrobenzyl-p-toluenesulfonate and 2,4-dinitrobenzyl-p-trifluoro-methylbenzenesulfonate ; And

(v) methane sulfonate esters of pyrogalic acid (pyrogallol trimesylate), benzene sulfonate esters of pyrogalic acid, p-toluene sulfonate esters of pyrogalic acid, p-methoxybenzenesulfonate esters of pyrogalic acid, pyrogalic acid Mesitylene sulfonate ester, pyrogalic acid benzenesulfonate ester, alkyl gallic acid methanesulfonate ester, alkyl gallic acid benzenesulfonate ester, alkyl gallic acid p-toluenesulfonate ester, alkyl gallic acid p-methoxybenzenesulfonate ester, Alkyl gallic acid mesitylene sulfonate esters and alkyl gallic acid benzyl sulfonate esters, and esters of silver polyhydroxy compounds with aliphatic or aromatic sulfonic acids; Etc. can be mentioned.

The alkyl group in the alkyl gallic acid is preferably an alkyl group having 1 to 15 carbon atoms, particularly an octyl group or a lauryl group.

As the component (VI), an onium salt acid generator represented by the following general formulas (II) and (III), and a benzoin tosylate acid generator represented by the following formula (IV) can be used as the component (VII). .

(Wherein R ⁴ , R ⁵ , and R ⁶ are an aryl group or an aryl group having a substituent and may be the same or different; X ⁻ is AsF ₆ ⁻ , SbF ₆ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ or CF ₃ SO ₃ ^- is of one kinds).

(Wherein R ⁷ and R ⁸ are an aryl group or an aryl group having a substituent and may be the same or different; R ⁹ and R ¹⁰ are a hydrogen atom, a lower alkyl group, a hydroxy group, or an aryl group, and are the same or different) N is 0 or 1).

Specific onium salts represented by the general formulas (II) and (III) include the following compounds;

Diphenyliodinium tetrafluoroborate

Diphenyl iodonium hexafluorophosphate

Diphenyl iodonium hexafluoroantimonate

Diphenyliodonium trifluoromethane sulfonate

(4-methoxyphenyl) phenyl iodonium hexafluoroantimonate

(4-methoxyphenyl) phenyliodonium trifluoromethane sulfonate

Bis (p-tert-butylphenyl) iodonium hexafluorophosphate

Bis (p-tert-butylphenyl) iodonium hexafluoroantimonate

Bis (p-tert-butylphenyl) iodonium trifluoromethane sulfonate

Bis (p-tert-butylphenyl) iodonium tetrafluoroborate

Triphenylsulfonium hexafluorophosphate

Triphenylsulfonium hexafluoroantimonate

Triphenylsulfonium trifluoromethane sulfonate

(4-methoxyphenyl) diphenylsulfonium hexafluoroantimonate

(4-methoxyphenyl) diphenylsulfonium trifluoromethane sulfonate

(4-methylphenyl) diphenylsulfonium trifluoromethane sulfonate

Bis (4-methylphenyl) phenylsulfonium trifluoromethane sulfonate

Tris (4-methylphenyl) sulfonium trifluoromethane sulfonate

(2,4,6-trimethylphenyl) diphenylsulfonium trifluoromethane sulfonate

(4-tert-butylphenyl) diphenylsulfonium trifluoromethane sulfonate

Diphenyl [4- (phenylthio) phenyl] sulfonium hexafluorophosphate

Diphenyl [4-phenylthio) phenyl] sulfonium hexafluoroantimonate.

Among the onium salts, trifluoromethane sulfonates which form anions are preferable in that the onium salts do not contain atoms such as phosphorus, boron, antimony and the like, which are used as the diffusion agent during the semiconductor device manufacturing process.

(vii) Specific examples of the benzoin tosylate acid generator include the following compounds;

One kind of the acid generator may be used, and two or more kinds thereof may be used in combination.

Among the acid generators, suitable for resists for excimer laser beams are bissulfonyl diazomethane, in particular bis (cyclohexylsulfonyl) diazomethane and bis (2,4-dimethylphenylsulfonyl) diazomethane and their And mixtures. Especially a mixture is more preferable because the composition containing the said mixture has high sensitivity. As the acid generator of the electron beam resist, an acid generator other than the above-mentioned (i) and (iii) can be used. Particularly preferred are nitrobenzyl derivatives of (IV), among which 2,6-dinitrobenzyl-P-toluenesulfonate; Polyhydroxy compounds of (V) and esters of aliphatic or aromatic sulfonic acids, inter alia pyrogallol trimesylate; Onium salts of (VI), in particular bis (p-tert-butylphenyl) iodonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate; And (VII) benzoin tosylate acid generators. The composition ratio of the acid generator in the composition of the present invention is 1-20 parts by weight, preferably 2-10 parts by weight with respect to 100 parts by weight of the resin component. If the acid generator is less than 1 part by weight, the effect is insufficient. When it exceeds 20 weight part of cotton, it will not melt | dissolve completely in a solvent and worses miscibility with resinous components.

An organic carboxylic acid compound can be added to the resist composition of the present invention, and the composition containing the same provides a resist pattern having good width characteristics at high sensitivity, high resolution, and depth of focus, and having a good profile. In particular, the composition containing an organic carboxylic acid compound provides a resist pattern having good post-exposure storage stability and having an excellent profile on various kinds of substrates.

The organic carboxylic acid compound used in the composition of the present invention includes saturated or unsaturated aliphatic carboxylic acid, alicyclic carboxylic acid, hydroxy-carboxylic acid, alkoxy-carboxylic acid, keto-carboxylic acid, aromatic carboxylic acid and the like.

For example, the acid compounds include aliphatic mono- or poly-carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid and adipic acid; Alicyclic carboxylic acids such as 1,1-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and 1,1-cyclohexyldiacetic acid; Unsaturated aliphatic carboxylic acids such as acrylic acid, crotonic acid, isocrotonic acid, 3-butenic acid, methacrylic acid, 4-pentenic acid, propiolic acid, 2-butynonic acid, maleic acid, fumaric acid and acetylene carboxylic acid; Hydroxycarboxylic acids such as hydroxy acetic acid; Alkoxycarboxylic acids such as methoxy acetic acid and ethoxy acetic acid; Keto carboxylic acids such as pyruvic acid; And aromatic carboxylic acid compounds represented by the following formula (V) or (VI); And the like.

(In the formula, R ¹¹ and R ¹² are each independently a hydrogen atom, a hydroxyl group, a nitro group, a carboxyl group or a vinyl group, except that both R ¹¹ and R ¹² are hydrogen atoms.)

Where n is 0 or an integer between 1 and 10.

Especially preferred are alicyclic carboxylic acid compounds, unsaturated aliphatic carboxylic acid compounds and aromatic carboxylic acid compounds.

Examples of the aromatic carboxylic acid compound of formula (V) include p-hydroxybenzoic acid, o-hydroxy benzoic acid, 2-hydroxy-3-nitrobenzoic acid, 3,5-dinitrobenzoic acid, 2-nitrobenzoic acid, 2,4-di Hydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2-vinylbenzoic acid, 4-vinylbenzoic acid phthalic acid And terephthalic acid and isophthalic acid. Particularly preferred are benzoic acid having a substituent at the o-position, for example o-hydroxybenzoic acid, 2-nitrobenzoic acid and phthalic acid.

As the aromatic carboxylic acid compound of the formula (VI), n may use a specific number of compounds or a combination of two or more other compounds.

In actual use, SAX (trade name, Mitsui Toatsu Chemical Co.) sold as a waste-solute compound is preferably used as an acid compound.

The aromatic carboxylic acid compounds represented by the general formulas (V) and (VI) may be used alone or in combination of two or more thereof.

The composition of this invention containing these aromatic carboxylic acid compounds can form the resist pattern with favorable cross-sectional shape. In addition, the positive resist composition of the present invention is excellent in storage stability after exposure and can form a resist pattern having a good profile irrespective of the time required before heat treatment after exposure. Particularly preferred are aromatic carboxylic acid compounds of formula (VI), because the present invention forms resist patterns having rectangular cross-sectional shapes when these compounds are contained.

The compounding quantity of the said organic carboxylic acid compound used for this invention is 0.01-1 weight% with respect to the sum of the resin component and acid generator in a composition, More preferably, it is the range of 0.07-3 weight% more than 0.05-0.5 weight%.

When the blending amount of the organic carboxylic acid compound is less than 0.01% by weight, a resist pattern having a good cross-sectional shape cannot be obtained. On the other hand, more than 1% by weight increases the loss of the resulting film in the unexposed areas. Thus, while the function of the organic carboxylic acid compound in the present invention is not clear, it is assumed that the organic carboxylic acid compound balances the acid generated by the exposure of the radiation in the resist composition. In addition to the above components, the present invention preferably contains a light absorber in order to improve sensitivity and resolution.

As such a light absorber, mercaptooxazole, mercaptobenzoxazole, mercaptooxazoline, mercaptobenzothiazole, benzooxazolinone, benzothiazolone, mercaptobenzoimidazole, urazol, thiouracil, mercap Topyrimidine, benzophenone and derivatives thereof.

Particularly preferred is benzophenol, which is excellent in improving the sensitivity and resolution of the composition containing the same, and at the same time suppresses the influence of standing waves on the resist composition, thereby preventing the wave from becoming rectangular. This is because it also has a function of forming a resist pattern having a cross section.

As a compounding quantity of this light absorber, it mix | blends in the range which does not exceed 30 weight% with respect to the sum total of said (A) component and (B) component, Preferably it mix | blends in the range of 0.5-15 weight%. When this compounding quantity exceeds 30 weight%, the profile shape of the resist pattern obtained by the composition containing this will worsen.

The present invention is preferably used in the form of a solution dissolved in the solvent.

Examples of such a solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone and 2-heptanone; Ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol mono acetate, dipropylene glycol, dipropylene glycol monoacetate and monomethyl ether, monoethyl ether, monopropyl ether, mono Polyhydric alcohols and derivatives thereof such as ethers such as butyl ether and monophenyl ether; Cyclic ethers such as dioxane; And esters such as methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methylmethoxy propionate, ethyl ethoxy propionate and the like. These can be used individually or in combination of 2 or more types.

The present invention may contain a conventional additive which is miscible as necessary, for example, an additive resin, a plasticizer, a stabilizer, a colorant, a surfactant, etc. for improving the performance of the resist film.

The positive resist composition of the present invention is dissolved in a solvent, and the resulting solution is coated with an insulating film such as silicon nitride film (SiN) or boron-in-silicate glass (BPSG) using a spinner, or a titanium nitride film. A metal film such as (TiN), Al-Si-Cu, or tungsten sut is applied to a coated substrate, and dried to form a photosensitive layer on the substrate, followed by deep-UV light (deep-UV light), The excimer laser beam is exposed through a desired mask pattern, or an image is formed by an electron beam, and developed with a developer such as a weakly alkaline aqueous solution containing 1-10% by weight of tetramethyl ammonium hydroxide. After this step, a good resist pattern faithful to the mask pattern is formed regardless of the type of substrate used.

Next, the present invention will be described in more detail with reference to Preparation Examples and Examples, which are illustrative only and are not intended to limit the scope of the present invention.

[Production Example 1]

(Preparation of polyhydroxy styrene in which 8 mol% of hydroxyl groups are substituted with tert-butoxycarbonyloxy group)

120 g of polyhydroxystyrene having a weight average molecular weight of 20000 and a molecular weight distribution (Mw / Mn) of 4.0 was dissolved in 680 g of N, N-dimethylacetamide, and 17.4 g of di-tert-butyl dicarbonate was added to the solution. Stir and dissolve completely. 59 g of triethylamine was then added dropwise over 15 minutes with stirring. After the addition was completed, the mixture was further stirred for 3 hours. Pure water was then added to the resulting solution in 20 times the solution. This was stirred again to precipitate polyhydroxystyrene in which the hydroxyl group was partially substituted with tert-butoxycarbonyloxy group. The precipitate was washed with pure water, dehydrated and dried to obtain 125 g of polyhydroxystyrene in which 8 mol% of the hydroxyl groups were substituted with tert-butoxycarbonyloxy groups.

[Production Example 2]

(Preparation of polyhydroxystyrene in which 35 mol% of hydroxyl groups are substituted with tert-butoxycarbonyloxy group)

Except that 76.5g of di-tert-butyl dicarbonates were added, 145g of polyhydroxystyrene in which 35 mol% of hydroxyl groups were substituted with tert-butoxycarbonyloxy group was obtained in the same manner as in Preparation Example 1.

[Manufacture example 3]

(Preparation of polyhydroxy styrene in which 39 mol% of hydroxyl groups are substituted with tert-butoxycarbonyloxy group)

Except that 85.0 g of di-tert-butyl dicarbonate was added, 150 g of polyhydroxystyrene in which 39 mol% of hydroxyl groups were substituted with tert-butoxy-carbonyloxy group was obtained in the same manner as in Preparation Example 1.

[Production Example 4]

(Preparation of polyhydroxy styrene in which 70 mol% of hydroxyl groups are substituted with tert-butoxycarbonyloxy group)

Except that 153 g of di-tert-butyl dicarbonate was added, 180 g of polyhydroxystyrene in which 70 mol% of the hydroxyl groups were substituted with tert-butoxycarbonyloxy group was obtained in the same manner as in Preparation Example 1.

Production Example 5

(Preparation of polyhydroxystyrene in which 35 mol% of hydroxyl groups are substituted with epoxyethoxy group)

120 g of polyhydroxystyrene having a weight average molecular weight of 20,000 and a molecular weight distribution (Mw / Mn) of 4.0 was dissolved in 680 g of N, N-dimethyl acetamide, and then 37.2 g of 1-chloro-1-ethoxyethane was added to the resulting solution. And stirred to dissolve completely. 78.8 g of triethylamine were then added dropwise over about 30 minutes with stirring. After the addition was completed, the mixture was stirred for about 3 hours again.

Then 20 times pure water of the solution was added and then stirred. As a result, 130 g of polyhydroxystyrene was obtained in which 35 mol% of the hydroxy group was partially substituted with 1-ethoxyethoxy group.

[Manufacture example 6]

(Preparation of polyhydroxystyrene in which 8 mol% of hydroxy groups are substituted with methoxy-n-propyloxy group)

120 g of polyhydroxystyrene having a weight average molecular weight of 20,000 and a molecular weight distribution (Mw / Mn) of 4.0 was dissolved in 680 g of N, N-dimethylacetamide, and then 8.6 g of 1-chloro-1-methoxypropane was added to the solution. After addition, the mixture was stirred and completely dissolved. Then 78.8 g of triethylamine was added dropwise thereto over 30 minutes with stirring. After addition the mixture was stirred for about 3 hours more. Pure water was then added to the resulting solution in 20 times the solution. The mixture was stirred again to precipitate polyhydroxystyrene in which a hydroxy group was partially substituted with 1-methoxy-n-propyloxy group. The precipitate was washed, dehydrated and dried to give 125 g of polyhydroxystyrene in which 8 mol% of the hydroxyl groups were substituted with 1-methoxy-n-propyloxy groups.

[Manufacture example 7]

(Preparation of polyhydroxystyrene in which 39 mol% of hydroxyl groups are substituted with methoxy-n-propyloxy group)

130 g of polyhydroxystyrene in which 39 mol% of the hydroxyl groups were substituted with 1-methoxy-n-propyloxy group in the same manner as in Preparation Example 6, except that 42.3 g of 1-chloro-1-methoxypropane was added. Got.

[Manufacture example 8]

(Preparation of polyhydroxystyrene in which 70 mol% of hydroxyl groups are substituted with methoxy-n-propyloxy group)

150 g of polyhydroxystyrene in which 70 mol% of the hydroxyl groups were substituted with 1-methoxy-n-propyloxy group in the same manner as in Preparation Example 6, except that 75.6 g of 1-chloro-1-methoxypropane was added. Got.

Example 1

1.48 g of polyhydroxystyrene (weight average molecular weight 20,000 Mw / Mn = 4.0) in which 35 mol% of the hydroxyl groups were substituted with tert-butoxycarbonyloxy groups, and 35 mol% of the hydroxyl groups were ethoxyethoxy 1.48 g of substituted polyhydroxystyrene (weight average molecular weight 20,000 Mw / Mn = 4.0) was dissolved in 16.8 g of propylene glycol monomethylether acetate, and bis (cyclohexylsulfonyl) diazomethane 0.148 g benzophenone 0.093 g And 0.0032 g of o-hydroxybenzoic acid were added for dissolution. The resulting solution was filtered through a 0.2 µm membrane filter to obtain a coating liquid of amphibious resist.

The coating liquid thus obtained was applied to a 6-inch silicon wafer using a spinner, and then dried at 90 ° C. for 90 seconds to form a resist film having a thickness of 0.7 mm on the wafer.

This was exposed to an excimer laser through a test chart mask using a reduced projection exposure machine NSR-2005EX 8A (manufactured by Nikon Corporation), followed by heating at 120 ° C. for 90 seconds, followed by heating in an aqueous solution of 2.38% by weight of tetramethylammonium hydroxide. After stirring for 2 seconds, the solution was washed with water for 30 seconds and then dried to form a resist pattern on the wafer. The resist pattern thus formed was a 0.21 μm line-and-space pattern. The cross-sectional shape of this resist pattern was good and the upper part was slightly rounded but was almost rectangular. This resist pattern was not affected by standing waves.

In addition, it was 7 mJ / cm ^{2 as} a result of measuring the amount (hereinafter, referred to as a minimum exposure amount) that the coated resist forms a pattern with a large area of the resist pattern that can be visually detected while exposing the substrate surface. In addition, the heat resistance of the 0.5 μm line pattern formed from the resist was measured, and the result was 130 ° C.

The depth of focus is defined as Class A when the maximum width (μm) of the focal point where the 0.25-μm line-and-space pattern is formed 1: 1 is 1.0 μm or more, and the maximum width is less than 1.0 μm as the Class B. Evaluated. As a result, the depth of focus was measured to be Class A. No storage of solids was observed for 6 months when the resist solution was stored at 25 ° C. in a brown bottle for storage stability evaluation.

This resist sheet was used, and the resist pattern was formed in the same manner as above except that it was left for 15 minutes after exposure and then heated at 120 ° C. for 90 seconds.

The resist pattern thus formed was a 0.21 μm line-and-space pattern with a good rectangular cross-sectional shape.

Example 2

A resist pattern was formed in the same manner as in Example 1 except that benzophenone was not added to the coating liquid of the positive resist. The resist pattern thus formed was a 0.23 μm line-and-space pattern. The cross-sectional shape of the resist pattern was slightly rounded at the upper end and wavy to be ignored for practical use, but was almost square. The minimum exposure to the resist was measured and found to be 8 mJ / cm 2. It was 130 degreeC when the heat resistance of the 0.5 micrometer line-space pattern formed from this resist was measured. As a result of measuring the width of the depth of focus in the same manner as in Example 1, it was 'Class A'. In addition, as a result of measuring the storage stability of the resist solution in the same manner as in Example 1, no solid substance was observed for 6 months.

Using the resist, the resist pattern was formed in the same manner as in Example 1 except that the resist was left to stand for 15 minutes after exposure and then heated at 120 ° C. for 90 seconds. The resist pattern thus formed was a 0.23 μm line-and-space pattern with a good rectangular cross-sectional shape.

Example 3

A resist pattern was formed in the same manner as in Example 1, except that 0.0062 g of SAX (trademark, manufactured by Mitsui Toatsu Chemical Co.) sold as a phenolic compound instead of o-hydroxy benzoic acid was used. The resist pattern thus formed was a 0.21 μm line-and-space pattern. The cross-sectional shape of this resist pattern was a good rectangular shape which is not influenced by standing waves. The minimum exposure amount of this resist was measured, and found to be 7 mJ / cm 2. It was 130 degreeC when the heat resistance of the 0.5 micrometer line-space pattern formed from this resist was measured.

As a result of measuring the width of the depth of focus in the same manner as in Example 1, it was determined as 'Class A'. In addition, as a result of evaluating the storage stability of the resist solution in the same manner as in Example 1, no solid material was observed for 6 months.

Using this resist, a resist pattern was formed in the same manner as in Example 1 except that the resist was left to stand for 15 minutes after exposure and then heated at 120 ° C. for 90 seconds. The resist pattern thus formed was a 0.21 μm line-and-space pattern with a good rectangular cross-sectional shape.

Example 4

A resist pattern was prepared in the same manner as in Example 1, except that 0.0062 g of acrylic acid was used instead of o-hydroxy benzoic acid. The resist pattern thus formed was a 0.21 μm line-and-space pattern. This resist pattern cross-sectional shape was favorable square without being influenced by standing waves. The minimum exposure amount of this resist was measured, and found to be 7 mJ / cm 2.

It was 130 degreeC when the heat resistance of the 0.5 micrometer line-space pattern formed from this resist was measured.

As a result of measuring the width of the depth of focus in the same manner as in Example 1, it was A class. Furthermore, as a result of evaluating the storage stability of the resist solution in the same manner as in Example 1, no solid material was observed for 6 months. Using this resist, a resist pattern was formed in the same manner as in Example 1 except that the resist was exposed and left for 15 minutes and then heated at 120 ° C. for 90 seconds.

The resist pattern thus formed was a 0.21 μm line-and-space pattern with a good rectangular cross-sectional shape.

Example 5

Preparation wherein 39 mol% of hydroxyl groups were substituted with tert-butoxycarbonyloxy group 1.05 g of polyhydroxystyrene of Preparation Example 3 and 39 mol% of hydroxyl groups were substituted with 1-methoxy-n-propyloxy group 1.95 g of polyhydroxystyrene of Example 7 was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, to which 0.21 g of bis (cyclohexylsulfonyl) diazomethane and 0.009 g of o-nitrobenzoic acid were added and dissolved. The resulting solution was filtered through a 0.2 µm membrane to obtain a coating solution of a positive resist.

The coating liquid thus obtained was applied onto a 6-inch silicon wafer using a spinner, and then dried at 90 ° C. for 90 seconds to form a resist film having a thickness of 0.7 μm on the wafer.

The film was exposed through a test chart mask using a reduced projection exposure machine NSR-2005EX 8A (manufactured by Nikon Corporation), heated at 110 ° C. for 90 seconds, and stirred for 65 seconds in an aqueous solution of 2.38 wt% tetramethylammonium hydroxide. After washing for 30 seconds with water and dried to form a resist pattern on the wafer. The resist pattern thus obtained was a 0.22 mu m line-and-space pattern. The cross-sectional shape of this resist pattern was somewhat wavy but practically negligible and was a good rectangle.

The minimum exposure was measured and found to be 15 mJ / cm 2. It was 130 degreeC when the heat resistance of the 0.5 micrometer line pattern formed from this resist was measured.

It was A class when the width of the depth of focus was measured in the same manner as in Example 1. Furthermore, the storage stability of the resist solution was measured by the method of Example 1 and no solid material was observed for 6 months.

Example 6

The resist properties were evaluated according to the method of Example 5 except that SAX (trade name, Mitsui Toatsu Chemical Co, product) was added instead of o-nitrobenzoic acid and 0.128 g of benzophenone was added. This resist was a 0.22 μm line-and-space pattern.

The cross-sectional shape of the resist pattern thus formed was a good rectangle without being influenced by standing waves. The minimum exposure amount of the resist was measured, and found to be 13 mJ / cm 2.

It was 130 degreeC when the heat resistance of the 0.5 micrometer line-space pattern formed from this was measured.

According to the method of Example 1, the width of the depth of focus was evaluated, and it was A class. Furthermore, when the storage stability of the resist solution was measured according to the method of Example 1, no solid material was observed for 6 months.

Example 7

A resist coating liquid was prepared in the same manner as in Example 5 except that 0.003 g of o-hydroxy benzoic acid was used instead of o-nitrobenzoic acid and 0.128 g of benzophenone was added. The properties of the resist thus obtained were evaluated in the same manner as in Example 5. This resist was a 0,22 μm line-and-space pattern. The cross-sectional shape of the resist pattern thus formed was a good rectangle without being influenced by standing waves. The minimum exposure amount of this resist was measured, and found to be 7 mJ / cm 2.

It was 130 degreeC when the heat resistance of the 0.5 micrometer line-space pattern formed from this resist was measured.

As a result of evaluating the depth of focal depth in the same manner as in Example 1, the depth of focal depth was Class A. Furthermore, as a result of measuring the storage stability of the resist solution in the same manner as in Example 1, no solid substance was observed for 6 months.

Example 8

A coating solution of the positive resist was prepared in the same manner as in Example 5 except that 0.009 g of 1,1-cyclohexanedicarboxylic acid was added instead of o-nitrobenzoic acid. The properties of the thus formed resist were evaluated in the same manner as in Example 5. This resist was a 0,21 μm line-and-space pattern. The cross-sectional shape of the resist pattern thus formed was somewhat wavy but was practically negligible. The minimum exposure to this resist was 13 mJ / cm 2. It was 130 degreeC when the heat resistance of the 0.5 micrometer line-space pattern formed from this resist was measured.

As a result of evaluation according to the method of Example 1, the depth of focus was Class A. In addition, the storage stability of the resist solution was evaluated in the same manner as in Example 1, no solid material was generated for 6 months.

Using the resist, the resist was left for 30 minutes after exposure and then subjected to heat treatment at 110 ° C. for 90 seconds to form a resist pattern as described above. The resist pattern thus obtained was a 0.21 μm line-and-space pattern of rectangular shape with good cross section.

Example 9

A positive resist coating liquid was prepared in the same manner as in Example 8 except that 0.12 g of benzophenone was added. Next, the resist properties were evaluated as in Example 8. This resist was formed with a line-and-space pattern of 0.21 mu m. The cross-sectional shape of this resist pattern was a good rectangle without influence of standing waves. The minimum exposure to this resist was 13 mJ / cm 2.

Moreover, it was 130 degreeC when the heat resistance of the 0.5 micrometer line pattern formed from the resist was evaluated.

As a result of the evaluation by the same method as in Example 1, the width of the depth of focus was Class A. In addition, in the storage stability test of the resist solution by the same method as in Example 1, no solid material was generated for 6 months.

The resist was left for 30 minutes after exposure and then heated at 110 ° C. for 90 seconds. The resist pattern obtained here was formed with a rectangular 0.21 mm line-and-space pattern having a good cross section.

Comparative Example 1

2.96 g of polyhydroxystyrene obtained in Preparation Example 2, in which 35 mol% of the hydroxyl group was substituted with tert-butoxycarbonyloxy group, was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, followed by triphenylsulfonium hexafluoro 0.09 g of roantimonate was added and dissolved. The resulting solution was filtered through a 0.2 μm membrane to obtain a positive resist coating solution.

Using the coating solution thus prepared, a resist pattern was formed in the same manner as in Example 1. However, the minimum micropattern limit of the resist was a 0.3 μm line-and-space pattern. The cross-sectional profile of the thus formed pattern was not good and widened upwards. The minimum exposure to the resist was measured and found to be 10 J / cm 2.

The heat resistance of the 0.5 μm line-space-pattern formed from this resist was measured at 140 ° C. In addition, the value of the depth of focus evaluated in the same manner as in Example 1 was 'class B'.

The resist was left to stand for 15 minutes after exposure and then heated at 120 ° C. for 90 seconds. The minimum fine pattern limit of this resist was a 0.5 μm line-and-space pattern. The cross-sectional profile of the thus formed pattern was T-shaped.

Comparative Example 2

2.96 g of polyhydroxystyrene obtained in Preparation Example 5 in which 35 mol% of the hydroxyl groups were substituted with an ethoxyethoxy group was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, followed by bis (cyclohexylsulfonyl) 0.148 g of diazomethane and 0.093 g of benzophenone were added and dissolved. The resulting solution was filtered through a 0.2 μm membrane filter to obtain a positive resist coating liquid. A resist pattern was formed in the same manner as in Example 1 using the coating solution thus prepared. However, the minimum fine pattern formation limit of the resist was 0.25 [mu] m line-and-space pattern. The cross-sectional profile of the pattern thus formed was not good as having an inverted triangle shape. The minimum exposure to the resist was measured and found to be 7 mJ / cm 2. It was 120 degreeC when the heat resistance of the 0.5 micrometer line-space pattern formed from this resist was measured.

Comparative Example 3

1.05 g of polyhydroxystyrene obtained in Preparation Example 1 in which 8% of the hydroxyl groups were substituted with tert-butoxycarbonyloxy group and in Preparation Example 6 in which 8% of the hydroxyl groups were substituted with the methoxy-n-propyloxy group 1.95 g of the obtained polyhydroxystyrene was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, to which 0.21 g of bis (cyclohexylsulfonyl) diazomethane, 0.009 g of o-nitrobenzoic acid and 0.128 g of benzophenone were added and dissolved. .

The resulting solution was filtered through a 0.2 μm membrane filter to obtain a positive resist coating liquid.

The coating solution thus prepared was attempted to evaluate the properties of the resist in the same manner as in Example 5, but failed to form a resist pattern.

[Comparative Example 4]

1.48 g of polyhydroxystyrene of Preparation Example 2, wherein 35 mol% of the hydroxyl group was substituted with tert-butoxycarbonyloxy group, and poly of Preparation Example 5, wherein 35 mol% of the hydroxyl group was substituted with the ethoxyethoxy group. 1.48 g of hydroxystyrene was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, and dissolved by adding 0.148 g of bis (cyclohexyl-sulfonyl) diazomethane and 0.093 g of benzophenone. The resulting solution was filtered through a 0.2 μm membrane filter to obtain a positive resist coating liquid.

The coating solution thus prepared was coated on a 6-inch silicon wafer using a Sipinner and then dried for 90 seconds on a high temperature plate at 90 ° C. to form a resist film having a thickness of 0.7 μm on the wafer. This was exposed through a test chart mask using a reduced projection exposure machine, NSR-2005EX8A (manufactured by Nikon), heated at 120 ° C. for 90 seconds, stirred for 65 seconds in an aqueous solution of 2.38% by weight of ammonium tetramethylammonium hydroxide, and washed with water for 30 seconds. After drying, a resist pattern was formed on the wafer. The resist pattern thus formed was a 0.21 μm line-and-space pattern. Although the cross-sectional profile of this resist pattern was slightly trapezoidal, it was good as a substantially rectangular shape. This resist pattern was not affected by standing waves. The minimum dosage was 7 mJ / cm 2. The heat resistance of the 0.5 micrometer line pattern formed from this resist was 130 degreeC.

The resist was left to stand for 15 minutes after exposure and then heated at 120 ° C. for 90 seconds. The cross-sectional profile of the thus formed resist pattern was T-shaped, and the minimum fine pattern formation limit of the resist was 0.3 μm line-and-space pattern.

[Comparative Example 5]

Preparation Example 8, in which 70% of the hydroxyl group was substituted with tert-butoxycarbonyloxy group. Preparation Example 8, in which 1.05 g of polyhydroxystyrene of Preparation Example 4 and 70% of the hydroxyl group were substituted with 1-methoxy-n-propyloxy group. 1.95 g of polyhydroxystyrene was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, and 0.21 g of bis (cyclohexylsulfonyl) diazomethane, 0.009 g of SAX (trademark, manufactured by Mitsui Toatsu Chemical Co.) and benzo 0.128 g of phenone was added and dissolved.

The resulting solution was filtered through a 0.2 μm membrane filter to obtain a coating solution of a positive resist. The properties of the thus formed resist were evaluated in the same manner as in Example 5. The limit of formation of the minimum fine pattern of the resist was a line-and-space pattern of 0.3 mu m. The cross-sectional formation of the pattern obtained by the resist was poor in T-shape. In addition, the minimum exposure amount to the resist was 20mJ / ㎠. It was 130 degreeC when the heat resistance of the 0.5-micrometer line-space pattern formed from the resist was examined.

Comparative Example 6

1.05 g of polyhydroxystyrene of Preparation Example 1 in which 8% of the hydroxyl groups were substituted with tert-butoxycarbonyloxy group, and Preparation Example in which 70% of the hydroxyl groups were substituted with 1-methoxy-n-propyloxy group 1.95 g of polyhydroxystyrene of 8 was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, to which 0.21 g of bis (cyclohexylsulfonyl) diazomethane, 0.009 g of phthalic acid and 0.128 g of benzophenone were added. . The resulting solution was filtered through a 0.2 µm membrane filter to obtain a coating liquid of a positive resist.

The properties of the thus formed resist were evaluated in the same manner as in Example 5.

The limit of formation of the minimum fine pattern of the resist was a line-and-space pattern of 0.3 mu m. The cross-sectional shape of the pattern obtained by the resist had a shape close to an inverted triangle and was poor. The minimum exposure to the resist was 10 mJ / cm 2. The heat resistance of the 0.5 mm line pattern formed from the resist was examined and found to be 130 degrees Celsius.

Example 10

A resist pattern was formed in the same manner as in Example 1, except that the substrate was a silicon wafer coated with a silicon nitride insulating film (SiN). The resist pattern thus obtained was a line-and-space pattern of 0.23 mu m. The cross-sectional shape of the resist pattern was a shape close to a rectangle without being influenced by standing waves.

Example 11

A resist pattern was formed in the same manner as in Example 1 except that the substrate was replaced with a silicon wafer coated with a TiN metal film. The resist pattern formed here was a line-and-space pattern of 0.23 mu m. The cross-sectional shape of the resist pattern was good close to a rectangle without the influence of standing waves.

Example 12

A resist pattern was formed in the same manner as in Example 5 except that the substrate was covered with a silicon wafer coated with a BPSG insulating film. The resist pattern obtained here was a line-and-space pattern of 0,23 mu m. As for the cross-sectional shape of the said resist pattern, the resist pattern cross section was a favorable shape close to a rectangle without influence of a standing wave.

Comparative Example 7

A resist pattern was formed in the same manner as in Comparative Example 1 except that the substrate was replaced with a silicon wafer coated with a SiN insulating film. The resist pattern formed here was a line-and-space pattern of 0.30 mu m. The cross-sectional shape of the resist pattern was a shape which expanded downward at the interface between the pattern and the substrate.

Comparative Example 8

A resist pattern was formed in the same manner as in Comparative Example 4 except that a silicon wafer coated with a SiN insulating film was used as the substrate. The cross-sectional profile of the resist pattern was swollen downward.

Example 13

0.9 g of polyhydroxystyrene obtained in Preparation Example 3, wherein 39 mol% of the hydroxyl group was substituted with tert-butoxycarbonyloxy group, and 35 mol% of the hydroxyl group was substituted with ethoxyethoxy group. 2.1 g of polyhydroxystyrene was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, to which 0.15 g of pyrogallol trimesylate and 6.3 mg of salicylic acid were added and dissolved. The resulting solution was filtered through a 0.2 µm membrane filter to obtain a coating liquid of a positive resist.

The coating solution thus prepared was coated on a 6-inch silicon wafer using a spinner, and then dried at 90 ° C. for 90 seconds to form a resist film having a thickness of 0.7 μm on the wafer.

The film was burned using an electron beam irradiator HL-8000 (manufactured by Hitachi), heated at 110 ° C. for 90 seconds, then stirred for 65 seconds in an aqueous solution of 2.38 wt% tetramethylammonium hydroxide, washed with water for 30 seconds, and dried. To form a resist pattern on the wafer. In this way, a contact hole of 0.12 mu m was formed. The cross-sectional shape of the resist pattern was a good rectangle. Moreover, it was 25 microC / cm <2> when the exposure amount at the time of this pattern process was measured.

Example 14

A positive resist coating solution was prepared in the same manner as in Example 13, except that pyrogalol trimesylate, an acid generator, was replaced with 0.15 g of bis (p-tert-butylphenyl) iodonium trifluoromethanesulfonate. .

Using this, the same process as in Example 1 to form a resist pattern. At this time, a contact hole of 0.15㎛ was formed. The cross-sectional shape of the resist pattern was good as a rectangle. In addition, the exposure amount at the time of this pattern process was 10 microC / cm <2>.

Example 15

A coating solution of the positive resist was prepared in the same manner as in Example 13 except that 0.15 g of 2,6-dinitrobenzyl p-toluene sulfonate was used instead of the pyrogallol trimesylate as an acid generator. Using this, the same process as in Example 13 was carried out to form a resist pattern. At this time, a contact hole of 0.14㎛ was formed. The cross-sectional shape of the resist pattern was a good rectangle. The exposure amount of this pattern process was 35 microC / cm <2>.

Example 16

A coating solution of a positive resist was prepared in the same manner as in Example 13 except that 0.15 g of triphenylsulfonium trifluoromethane sulfonate was used instead of the pyrogallol trimesylate as an acid generator. Using this, the same process as in Example 13 was carried out to form a resist pattern. At this time, a contact hole of 0.15 mm was formed. The cross-sectional shape of the formed resist pattern was a good rectangle. In addition, the exposure amount of this pattern process was 10 mC / cm <2>.

Example 17

0.9 g of polyhydroxystyrene obtained in Preparation Example 3 in which 39 mol% of the hydroxyl group was substituted with tert-butoxycarbonyloxy group, and 39 mol% of the hydroxyl group were substituted with 1-methoxy-n-propyloxy group. 2.1 g of polyhydroxystyrene obtained in Production Example 7 was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, and then 0.03 g of bis (cyclohexylsulfonyl) diazomethane 0.02 g bis (2,4-dimethylphenylsulfonyl) diazo 0.15 g of methane and 0.0064 g of o-hydroxybenzoic acid were added and dissolved. As a result, the solution was filtered through a 0.2 µm membrane filter to obtain a positive resist coating liquid.

The properties of the thus formed resist were evaluated as in Example 5. This resist gave a 0.2 μm line-and-space pattern. The cross-sectional profile of the thus formed resist pattern was good and rectangular, slightly wavy or negligible.

The minimum exposure to the resist was 5 mJ / cm 2. It was 130 degreeC when the heat resistance of the 0.5 mm line-space pattern formed from this resist was measured.

In the same manner as in Example 1, the width of the depth of focus was Class A. In addition, when evaluated in the same manner as in Example 1, no solid matter was observed for 6 months in the storage stability test of the resist solution.

Claims (16)

(i) a resin component (A) in which solubility in an aqueous alkali solution is increased by the action of an acid, a compound (B) and an organic carboxylic acid compound (C) which generate an acid upon irradiation; and the resin component (A) Is (a) polyhydroxystyrene in which 10-60% by weight of the hydroxyl group is substituted with a residue of the general formula (I) (Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a methyl group or an ethyl group and R ³ is a lower alkyl group having 1-4 carbon atoms); And (b) coating the surface of the substrate with a positive resist composition comprising a mixture of polyhydroxystyrene in which 10-60 mole% of the hydroxyl groups are substituted with tert-butoxycarbonyloxyl groups; (ii) selectively exposing the resist layer to actinic light; (iii) heating the exposed resist layer; And (iv) developing the resultant resist layer to form a desired pattern using a developing solution; and forming a patterned resist layer on the substrate. The method of claim 1, wherein the resin component (A) (a) polyhydroxystyrene having a weight average molecular weight of 8,000-22,000, wherein 10-60 mol% of the hydroxyl group is substituted with a residue of formula (I), (Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a methyl group or an ethyl group, and R ³ represents a lower alkyl group having 1-4 carbon atoms); And (b) a mixture consisting of polyhydroxystyrene having a weight average molecular weight of 8,000-22,000, wherein 10-60 mol% of the hydroxyl groups are substituted with tert-butoxycarbonyloxy groups The method of claim 1, wherein component (A) (a) 10-60 mol% of the hydroxyl group is substituted with a residue of the general formula (I), the weight average molecular weight is 8,000-22,000, polyhydroxystyrene having a molecular weight distribution (Mw / Mn) of 3-5, (Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a methyl group or an ethyl group, and R ³ is a lower alkyl group having 1-4 carbon atoms); And (b) polyhydroxystyrene having 10-60 mol% of the hydroxyl group substituted with tert-butoxycarbonyloxy group, a weight average molecular weight of 8,000-22,000, and a molecular weight distribution (Mw / Mn) of 3-5; Method comprising a mixture comprising a. The method of claim 1 wherein component (A) is a mixture of 30-90 weight percent of component (a) and 10-70 weight percent of component (b). The method of claim 1 wherein component (A) is a mixture of 50-80% by weight of component (a) and 20-50% by weight of component (b). The method of claim 1, wherein component (B) is a bissulfonyldiazomethane-based acid generator. The component (B) is an aliphatic and aromatic sulfonic acid ester of an nitrobenzyl acid generator, a polyhydroxy compound acid generator, an onium salt acid generator, and benzoin tosylate. At least one member selected from the group consisting of acid generators. The method of claim 1, wherein the content of component (B) is 1-20 parts by weight based on 100 parts by weight of component (A). The method of claim 10, wherein component (C) is at least one member selected from the group consisting of an aromatic carboxylic acid compound, an alicyclic carboxylic acid, and an unsaturated aliphatic carboxylic acid compound. The method of claim 9, wherein the aromatic carboxylic acid compound is a compound represented by the following general formula (V). (Wherein R ¹¹ and R ¹² are each independently a hydrogen atom, a hydroxyl group, a nitro group, a carboxyl group or a vinyl group, except that both R ¹¹ and R ¹² are hydrogen atoms.) The method of claim 9, wherein the aromatic carboxylic acid compound is a compound represented by the following general formula (VI) (Wherein n is an integer of 0 or 1-10) 10. The method according to claim 9, wherein the slow-limiting carboxylic acid compound is 1,1-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and 1,1 At least one member selected from the group consisting of cyclohexyl diacetic acid The method of claim 9, wherein the unsaturated aliphatic carboxylic acid is acrylic acid, crotonic acid, isocrotonic acid, 3-butenic acid, methacrylic acid, 4-phenenic acid, propiolic acid, 2-butynonic acid, maleic acid, fumaric acid and acetylene carboxylic acid. At least one selected from the group consisting of The method of claim 1, wherein the content of component (c) is 0.01-1% by weight based on the sum of the components (a) and (b). The method of claim 1, wherein the positive resist composition additionally comprises a light absorber. The method of claim 15, wherein the light absorber is benzophenone.