KR20240140774A - Photosensitive resin composition, resist film, resist underlayer film and resist permanent film - Google Patents

Abstract

[Problem] To provide a positive photosensitive resin composition having alkaline solubility, affinity for a photosensitive agent, low-temperature curing properties and low volume shrinkage properties when formed into a resist film, which are not present in conventional positive photosensitive resin compositions.
[Solution] A positive type photosensitive resin composition containing the following components (A) to (D): (A) a novolac-type phenol resin in which the molar ratio [(a1):(a2):(a3)] of a structural unit (a1) derived from m-cresol, a structural unit (a2) derived from benzaldehyde, and a structural unit (a3) derived from salicylaldehyde is 1.0:0.3 to 0.8:0.3 to 0.8 / (B) a photosensitive agent / (C) a thermal crosslinking agent / (D) an organic solvent

Description

Photosensitive resin composition, resist film, resist underlayer film and resist permanent film {PHOTOSENSITIVE RESIN COMPOSITION, RESIST FILM, RESIST UNDERLAYER FILM AND RESIST PERMANENT FILM}

The present invention relates to a photosensitive resin composition, a resist film, a resist underlayer film, and a resist permanent film.

Recently, along with the miniaturization of electronic devices, the density of semiconductor packages is increasing. The density of semiconductor packages is linked to the demand for further miniaturization of semiconductor elements, and the formation of microscopic patterns of several micrometers is required for surface passivation films, interlayer insulating films, etc.

In the past, positive type photosensitive resin compositions using polyimide resins, etc., which have excellent heat resistance and mechanical properties, have been widely used for surface protective films and interlayer insulating films of semiconductor devices. Normally, polyimide resins are formed into resin films by cyclizing their precursor films by heat curing. The resin films have excellent heat resistance and mechanical properties. However, positive type photosensitive resin compositions using polyimide precursors have a problem in that volume shrinkage occurs due to dehydration during heat curing, resulting in loss of film thickness and deterioration of dimensional accuracy. In addition, although a film formation process at a low temperature has been desired recently, there is a problem in that satisfactory physical properties cannot be obtained because imidization is incomplete when polyimide is cured at a low temperature.

Therefore, a positive type photosensitive resin composition using a phenol resin, a photosensitizer, and a thermal cross-linking agent, which does not cause dehydration by heat curing, is curable at low temperatures, and further has excellent mechanical properties after curing, has been proposed (for example, Patent Document 1). However, in the positive type photosensitive resin composition described in Patent Document 1, the base phenol resin has poor alkaline solubility and photosensitive agent affinity, and is therefore unsuitable for forming fine patterns.

Therefore, in order to realize fine pattern formation, a positive type resin composition using a modified phenol resin has also been proposed (for example, Patent Document 2). However, in the positive type photosensitive resin composition described in Patent Document 2, there are still problems with the alkaline solubility of the phenol resin and the affinity for the photosensitive agent, and satisfactory fine pattern formation has not been realized.

Japanese Special Publication No. 2004-258070 International Publication No. 2009/063808

With the increase in density of semiconductor packages and miniaturization of patterns, there is a demand for the development of a positive photosensitive resin composition comprising a phenol resin having high alkaline solubility and high affinity for a photosensitive agent, and having low-temperature curing properties and low volume shrinkage properties when used as a resist film.

The purpose of the present invention is to provide a positive type photosensitive resin composition which has alkaline solubility, affinity for a photosensitive agent, low-temperature curing properties and low volume shrinkage properties when formed into a resist film, which are not present in conventional positive type photosensitive resin compositions.

The present inventors, as a result of extensive studies to solve the above-mentioned problems, have found that a positive photosensitive resin composition comprising a novolak-type phenol resin composition having a specific structural unit, a photosensitive agent, a thermal cross-linking agent, and an organic solvent is excellent in alkaline solubility and photosensitive agent affinity, and further excellent in low-temperature curing properties and low volume shrinkage properties when formed into a resist film, thereby completing the present invention.

That is, the present invention relates to a positive photosensitive resin composition containing the following components (A) to (D).

(A) Novolac-type phenol resin having a molar ratio [(a1):(a2):(a3)] of a structural unit (a1) derived from m-cresol, a structural unit (a2) derived from benzaldehyde, and a structural unit (a3) derived from salicylaldehyde, of 1.0:0.3 to 0.8:0.3 to 0.8

(B) Photosensitive agent

(C) Thermal crosslinking agent

(D) Organic solvent

The present invention also relates to a photosensitive film obtained by drying a positive photosensitive resin composition.

The present invention also relates to a resist film obtained from a positive photosensitive resin composition.

The present invention also relates to a resist underlayer film obtained from a positive photosensitive resin composition.

The present invention also relates to a permanent resist film obtained from a positive photosensitive resin composition.

According to the present invention, it is possible to provide a positive photosensitive resin composition having excellent alkaline solubility and photosensitizer affinity, and further having excellent low-temperature curing properties and low volume shrinkage properties when formed into a resist film.

[Figure 1] This is a GPC chart of the novolac-type phenol resin obtained in Synthesis Example 1.
[Figure 2] This is a GPC chart of the novolac-type phenol resin obtained in Synthesis Example 2.
[Figure 3] This is a GPC chart of the novolac-type phenol resin obtained in Synthesis Example 3.
[Figure 4] This is a GPC chart of the novolac-type phenol resin obtained in Synthesis Example 4.
[Figure 5] This is a GPC chart of the novolac-type phenol resin obtained in Synthesis Example 5.

Below, a form for carrying out the invention is described.

In addition, in this specification, "x~y" indicates a numerical range of "x or more and y or less." The upper and lower limits described for the numerical range can be arbitrarily combined.

In addition, a form in which two or more of the individual forms of the present invention described below are combined is also a form of the present invention.

[Positive photosensitive resin composition]

A positive photosensitive resin composition according to one embodiment of the present invention contains the following components (A) to (D).

(A) Novolac-type phenol resin having a molar ratio [(a1):(a2):(a3)] of a structural unit (a1) derived from m-cresol, a structural unit (a2) derived from benzaldehyde, and a structural unit (a3) derived from salicylaldehyde, of 1.0:0.3 to 0.8:0.3 to 0.8

(B) Photosensitive agent

(C) Thermal crosslinking agent

(D) Organic solvent

In this embodiment, by using the novolak-type phenol resin of the above (A), a resist film having excellent affinity for a photosensitive agent in addition to high alkaline solubility is obtained.

Below, the components of the positive photosensitive resin composition are described.

·Component (A)

The novolac-type phenol resin, which is component (A), has a molar ratio [(a1):(a2):(a3)] of a structural unit (a1) derived from m-cresol, a structural unit (a2) derived from benzaldehyde, and a structural unit (a3) derived from salicylaldehyde of 1.0:0.3 to 0.8:0.3 to 0.8.

The molar ratio [(a1):(a2):(a3)] of the structural unit (a1) derived from m-cresol, the structural unit (a2) derived from benzaldehyde, and the structural unit (a3) derived from salicylaldehyde of the component (A) is preferably 1.0:0.5 to 0.7:0.3 to 0.5, more preferably 1.0:0.55 to 0.65:0.35 to 0.45, from the viewpoint of obtaining a resist film having high alkaline solubility, photosensitive agent affinity, low-temperature curing property, and low volume shrinkage.

Component (A) may contain structural units other than the structural unit (a1) derived from m-cresol, the structural unit (a2) derived from benzaldehyde, and the structural unit (a3) derived from salicylaldehyde. As structural units other than (a1) to (a3), structural units derived from phenols or aldehydes other than m-cresol, benzaldehyde, and salicylaldehyde can be exemplified.

Examples of the above phenols include phenol, o-cresol, p-cresol, 2,3-xylenol, 2,5-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, and 3,4,5-trimethylphenol.

Examples of the above aldehydes include formalin, paraformaldehyde, acetaldehyde, chloroacetaldehyde, 4-hydroxybenzaldehyde, and 3-hydroxybenzaldehyde.

In component (A), the total content of the structural units (a1), (a2) and (a3) is preferably 30 mass% or more, more preferably 50 mass% or more, and even more preferably 90 mass% or more, from the viewpoint of obtaining a resist film having high alkaline solubility, photosensitive agent affinity, low-temperature curing property and low volume shrinkage.

The total content of the above structural units (a1), (a2) and (a3) may be substantially 100 mass%. In addition, substantially 100 mass% means a case where structural units other than the above structural units (a1), (a2) and (a3) are inevitably included.

The weight average molecular weight of the novolac-type phenol resin, which is component (A), is preferably 1000 or more, more preferably 1500 or more. In addition, it is preferably 7000 or less, more preferably 6000 or less, and even more preferably 500 or less. When the weight average molecular weight is 1000 or more, it is preferable because the low-temperature curing property and the low volume shrinkage property are excellent. On the other hand, when the weight average molecular weight is 7000 or less, it is preferable because the alkali solubility and the photosensitizer affinity are excellent. In addition, in the present specification, the weight average molecular weight is measured according to the conditions described in the examples.

Component (A) is obtained by polycondensing m-cresol, benzaldehyde, and salicylaldehyde in an organic solvent using an acid catalyst at a molar ratio (m-cresol:benzaldehyde:salicylicaldehyde) of 1.0:0.3 to 0.8:0.3 to 0.8.

The molar ratio of m-cresol, benzaldehyde, and salicylaldehyde (m-cresol:benzaldehyde:salicylicaldehyde) in the reaction solvent is preferably in the range of 1.0:0.5 to 0.7:0.3 to 0.5, more preferably 1.0:0.55 to 0.65:0.35 to 0.45, from the viewpoint of obtaining a resist film having high alkaline solubility, photosensitive agent affinity, low-temperature curing property, and low volume shrinkage.

It is desirable that the molar ratio of benzaldehyde be smaller than that of salicylaldehyde. That is, it is desirable to satisfy the following relation: benzaldehyde < salicylaldehyde (mole ratio).

When m-cresol, benzaldehyde, and salicylaldehyde are polycondensed in an organic solvent to obtain a novolac-type phenol resin as component (A), as described above, phenols and aldehydes other than m-cresol, benzaldehyde, and salicylaldehyde may be contained in the organic solvent.

The ratio of the total mass of m-cresol, benzaldehyde, and salicylaldehyde to the total mass of all starting materials that can become structural units constituting component (A) in the reaction solvent, from the viewpoint of obtaining a resist film having high alkaline solubility, affinity for a photosensitive agent, low-temperature curing property, and low volume shrinkage, is preferably 30 mass% or more, more preferably 50 mass% or more, and even more preferably substantially 100 mass%.

Examples of the reaction solvent used in the production of component (A) include methanol, ethanol, 1-propanol, 2-propanol, butanol, hexanol, ethylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, methyl ethyl ketone, methyl isobutyl ketone, toluene, and the like. Among these, at least one selected from the group consisting of ethanol, 1-propanol, and 2-propanol is preferable, and ethanol is more preferable.

The amount of the above reaction solvent to be used is, from the viewpoint of the uniformity of the reaction, preferably 20 parts by mass or more, more preferably 50 parts by mass or more, per 100 parts by mass of the raw material for inducing the structural unit constituting component (A). In addition, it is preferably 500 parts by mass or less, more preferably 300 parts by mass or less.

Examples of acid catalysts used in the production of component (A) include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and boric acid; and organic acids such as oxalic acid, acetic acid, and para-toluenesulfonic acid. Among these, in order to further promote the reaction, inorganic acids and para-toluenesulfonic acid are preferable, and para-toluenesulfonic acid is more preferable.

The amount of the acid catalyst to be added is not particularly limited, but is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, per 100 parts by mass of the raw material for inducing the structural unit constituting component (A). In addition, it is preferably 150 parts by mass or less, more preferably 100 parts by mass or less.

The reaction temperature when condensing the raw material of component (A) is preferably 30°C or higher, more preferably 40°C or higher, in order to promote the reaction and also efficiently increase the molecular weight. In addition, it is preferably 100°C or lower, more preferably 80°C or lower.

The reaction time is preferably 4 hours or longer, more preferably 12 hours or longer. Also, it is preferably 32 hours or shorter, more preferably 24 hours or shorter.

·Component (B)

The photosensitive agent, which is component (B), can improve the sensitivity during exposure by promoting alkali solubilization of the exposed portion of the coating film of the positive photosensitive resin composition.

From the viewpoint of imparting high photosensitizer affinity to the positive type photosensitive resin composition of the present invention, the photosensitizer is preferably a quinonediazide-based photosensitizer.

Quinonediazide photosensitizers include compounds having a quinonediazide group. Specific examples of compounds having a quinonediazide group include aromatic (poly)hydroxy compounds, and complete ester compounds, partial ester compounds, amidates, or partial amidates of sulfonic acids having a quinonediazide group, such as naphthoquinone-1,2-diazide-5-sulfonic acid, naphthoquinone-1,2-diazide-4-sulfonic acid, and orthoanthraquinonediazidesulfonic acid.

Aromatic (poly)hydroxy compounds include, for example, 2,3,4-trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, 2,3,6-trihydroxybenzophenone, 2,3,4-trihydroxy-2'-methylbenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,3',4,4',6-pentahydroxybenzophenone, 2,2',3,4,4'-pentahydroxybenzophenone, 2,2',3,4,5-pentahydroxybenzophenone, Polyhydroxybenzophenone compounds such as 2,3',4,4',5',6-hexahydroxybenzophenone and 2,3,3',4,4',5'-hexahydroxybenzophenone;

Bis[(poly)hydroxyphenyl]alkane compounds such as bis(2,4-dihydroxyphenyl)methane, bis(2,3,4-trihydroxyphenyl)methane, 2-(4-hydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(2,4-dihydroxyphenyl)-2-(2',4'-dihydroxyphenyl)propane, 2-(2,3,4-trihydroxyphenyl)-2-(2',3',4'-trihydroxyphenyl)propane, 4,4'-{1-[4-〔2-(4-hydroxyphenyl)-2-propyl〕phenyl]ethylidene}bisphenol, and 3,3'-dimethyl-{1-[4-〔2-(3-methyl-4-hydroxyphenyl)-2-propyl〕phenyl]ethylidene}bisphenol;

Tris(hydroxyphenyl)methane compounds or methyl substituted products thereof, such as tris(4-hydroxyphenyl)methane, bis(4-hydroxy-3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-3,4-dihydroxyphenylmethane;

Bis(3-cyclohexyl-4-hydroxyphenyl)-3-hydroxyphenylmethane, bis(3-cyclohexyl-4-hydroxyphenyl)-2-hydroxyphenylmethane, bis(3-cyclohexyl-4-hydroxyphenyl)-4-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-2-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-3-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-4-hydroxyphenylmethane, bis(3-cyclohexyl-2-hydroxyphenyl)-3-hydroxyphenylmethane, Bis(5-cyclohexyl-4-hydroxy-3-methylphenyl)-4-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-3-methylphenyl)-3-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-3-methylphenyl)-2-hydroxyphenylmethane, bis(3-cyclohexyl-2-hydroxyphenyl)-4-hydroxyphenylmethane, bis(3-cyclohexyl-2-hydroxyphenyl)-2-hydroxyphenylmethane, bis(5-cyclohexyl-2-hydroxy-4-methylphenyl)-2-hydroxyphenylmethane, bis(5-cyclohexyl-2-hydroxy-4-methylphenyl)-4-hydroxyphenylmethane, etc., bis(cyclohexylhydroxyphenyl)(hydroxyphenyl)methane Examples thereof include compounds or methyl substituents thereof.

These photosensitizers may be used alone, or two or more types may be used in combination.

A single type of photosensitizer may be used alone, or two or more types may be used in combination.

In the present embodiment, the amount of the photosensitive agent blended is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, per 100 parts by mass of component (A), in order to obtain a positive photosensitive resin composition having excellent photosensitivity and excellent photosensitive agent affinity. Furthermore, it is preferably 50 parts by mass or less, more preferably 30 parts by mass or less.

·Component (C)

The thermal cross-linking agent, which is component (C), refers to a compound that forms a cross-linking structure in the resist film when a pattern is formed on a film of a positive type photosensitive resin composition and then cured by heating. In the present embodiment, if component (C) is not included, the positive type photosensitive resin composition does not sufficiently cure when formed into a resist film.

The thermal cross-linking agent is not particularly limited, and a known thermal cross-linking agent can be used. As the thermal cross-linking agent, for example, an epoxy-based thermal cross-linking agent or a hydroxymethylamino-based thermal cross-linking agent can be mentioned. In the present embodiment, from the viewpoint of obtaining a resist film having low-temperature curing properties and low volume shrinkage properties, a hydroxymethylamino-based thermal cross-linking agent is preferable.

An epoxy-based thermal crosslinking agent is one that uses a compound having an epoxy group as a thermal crosslinking agent. Examples of the epoxy-based thermal crosslinking agent include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, alicyclic epoxy resin, glycidylamine, heterocyclic epoxy resin, and polyalkylene glycol diglycidyl ether.

Hydroxymethylamino thermal crosslinking agents are compounds having a hydroxymethylamino group that are used as thermal crosslinking agents. Examples of hydroxymethylamino thermal crosslinking agents include (poly)(N-hydroxymethyl)melamine. Specific examples thereof include melamine resins such as hexakis(methoxymethyl)melamine and hexakis(butoxymethyl)melamine. In addition, examples of hydroxymethylamino thermal crosslinking agents include urea resins. Specific examples thereof include Nikalac MX-270, MX-280, MX-290 (manufactured by Sanwa Chemical Co., Ltd.).

A thermal cross-linking agent may be used alone, or two or more types may be used in combination.

The amount of the cross-linking agent to be blended is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, per 100 parts by mass of component (A), from the viewpoint of obtaining good sensitivity and obtaining a desired pattern. In addition, it is preferably 30 parts by mass or less, more preferably 20 parts by mass or less.

·Component (D)

The positive photosensitive resin composition of the present embodiment contains an organic solvent as component (D).

Examples of organic solvents include polar aprotic solvents such as N-methyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; ethers such as tetrahydrofuran, dioxane, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; ketones such as acetone, methyl ethyl ketone, and diisobutyl ketone; esters such as ethyl acetate, butyl acetate, isobutyl acetate, propyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and 3-methyl-3-methoxybutyl acetate; alcohols such as ethyl lactate, methyl lactate, diacetone alcohol, and 3-methyl-3-methoxybutanol; and aromatic hydrocarbons such as toluene and xylene. These organic solvents may be used alone, or two or more may be used in combination.

The amount of the organic solvent blended in the positive photosensitive resin composition of the present embodiment is such that the solid content concentration in the composition is preferably 5 mass% or more, from the viewpoint of obtaining a uniform coating film by a coating method such as spin coating, with the fluidity of the composition. Furthermore, it is preferably 65 mass% or less.

·etc

In one embodiment, in addition to the components (A) to (D) described above, various additives may be blended into the positive photosensitive resin composition within a range that does not impede the effects of the present invention. Examples of the additives include surfactants such as fillers, pigments, and leveling agents, adhesion enhancers, and dissolution accelerators.

The positive photosensitive resin composition of the present embodiment can be prepared by mixing the above-described components (A) to (D) and, if necessary, various additives by a conventional method through stirring to form a uniform liquid.

When mixing solid materials such as fillers and pigments into the composition, it is preferable to disperse and mix them using a dispersing device such as a dissolver, a homogenizer, or a three-roll mill. In addition, the composition may be filtered using a mesh filter, a membrane filter, or the like to remove granulation or impurities.

The positive photosensitive resin composition of the present embodiment can be suitably used for applications such as resist films, resist underlayer films, and resist permanent films. In addition, it can be suitably used for thick-film resists (bump-forming resists), interlayer insulating films, liquid crystal alignment films, heat-resistant imparting agents, display bank agents (pixel division layers), and the like.

The positive photosensitive resin composition of the present invention can be used in the same manner as a general positive photosensitive resin composition to form a photosensitive film, a resist film, a resist underlayer film, and a resist permanent film (hereinafter, the photosensitive film, the resist film, the resist underlayer film, and the resist permanent film may be collectively referred to as a resist film, etc.).

Specifically, by applying the positive photosensitive resin composition of the present invention onto an object to be subjected to photolithography and prebaking, a film (photosensitive film) of the photosensitive resin composition from which the organic solvent has been removed is obtained.

Examples of the coating method include spin coating, roll coating, flow coating, dip coating, spray coating, and doctor blade coating. Prebaking may be performed, for example, by heating at a temperature of 60°C or more and 150°C or less for 30 seconds or more and 600 seconds or less. In addition, the positive photosensitive resin composition of the present invention can suitably select a glass substrate, a silicon substrate, an aluminum substrate, a silicon carbide substrate, a silicon nitride substrate, a gallium nitride substrate, a transparent conductive film, a copper substrate, a copper plating substrate, or the like as a target of coating.

By exposing the photosensitive film, the solubility of the exposed area in an alkaline developer is greatly increased by the catalytic reaction of the acid. As a light source used for exposure, examples thereof include infrared light, visible light, ultraviolet light, ultraviolet light, X-rays, and electron beams. Among these light sources, ultraviolet light is preferable, and the g-line (wavelength 436 nm) and i-line (wavelength 365 nm) of a high-pressure mercury lamp are suitable.

After exposure, heat treatment at around 100℃ to 150℃ is possible.

The photosensitive film obtained from the positive type photosensitive resin composition of the present invention enables high-resolution patterning since the exposed portion has high alkaline solubility and further has a large difference in alkaline solubility from the unexposed portion. Therefore, it can be suitably used for a resist film, etc. In addition, the resist film, etc. in the present invention includes either a photosensitive film before exposure or a non-photosensitive film after exposure.

Examples of the alkaline developer used in development after exposure include alkaline aqueous solutions of inorganic alkaline substances such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and ammonia water; primary amines such as ethylamine and n-propylamine; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; and cyclic amines such as pyrrole and piperidine.

In the alkaline developer, alcohol, surfactant, etc. can be added appropriately as needed. The alkali concentration of the alkaline developer is usually preferably in the range of 2 to 5 mass%, and a 2.38 mass% tetramethylammonium hydroxide aqueous solution is generally used.

When the positive type photosensitive resin composition of the present invention is used for a resist underlayer film (BARC film), the positive type photosensitive resin composition of the present invention may be used as a composition for a resist underlayer film as is, and further, various additives such as other resin components, surfactants, dyes, fillers, crosslinking agents, and dissolution accelerators may be added as necessary.

As other resin components, for example, various novolak resins, addition polymerization resins of alicyclic diene compounds such as dicyclopentadiene and phenolic compounds, modified novolak resins of phenolic hydroxyl group-containing compounds and alkoxy group-containing aromatic compounds, phenol aralkyl resins (xyloxy resins), naphthol aralkyl resins, trimethylol methane resins, tetraphenylol ethane resins, biphenyl-modified phenol resins, biphenyl-modified naphthol resins, aminotriazine-modified phenol resins, and various vinyl polymers can be mentioned.

When using other resin components, the mixing ratio of the positive photosensitive resin composition of the present invention and the other resin can be arbitrarily set according to the intended use. For example, it is preferable that the other resin be in a ratio of 0.5 to 100 parts by mass with respect to 100 parts by mass of component (A).

The composition for a resist underlayer film can be prepared by blending the above-mentioned components and mixing them using a stirrer or the like. In addition, when the composition for a resist underlayer film contains a filler or pigment, it can be prepared by dispersing or mixing them using a dispersing device such as a dissolver, a homogenizer, or a three-roll mill.

In order to form a resist underlayer film from a composition for a resist underlayer film, for example, there is a method in which the above-described composition for a resist underlayer film is applied onto a target for photolithography, such as a silicon substrate, dried under temperature conditions of 100 to 200°C, and then further heat-cured under temperature conditions of 250 to 400°C. Then, a normal photolithography operation is performed on the underlayer film to form a resist pattern, and by performing dry etching treatment with a halogen-based plasma gas or the like, a resist pattern can be formed by a multilayer resist method.

When the positive photosensitive resin composition of the present invention is used for permanent resist film purposes, in addition to the components (A) to (D) of the present invention, additives such as other resins, surfactants, dyes, fillers, crosslinkers, and dissolution accelerators may be added as needed. Examples of other resins used herein include those similar to those used in compositions for resist underlayer films.

A method of photolithography using a composition for a permanent resist film is, for example, to dissolve and disperse other resin components and additive components in the positive photosensitive resin composition of the present invention, apply it on an object to be subjected to photolithography, and prebake it under temperature conditions of 60 to 150°C. The application method at this time may be any method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor blade coating. Next, a target resist pattern is exposed through a predetermined mask, and the exposed portion is dissolved with an alkaline developer, thereby forming a resist pattern.

The resist permanent film of the present embodiment can be suitably used, for example, in relation to semiconductor devices, as a solder resist, a packaging material, an underfill material, a package adhesive layer for circuit elements, or an adhesive layer for an integrated circuit element and a circuit board, and in relation to thin displays such as LCD and OLED, as a thin film transistor protective film, a liquid crystal color filter protective film, a black matrix, a spacer, and the like.

[Example]

Hereinafter, the present invention will be described in more detail with specific examples. In addition, the weight average molecular weight (Mw) of the synthesized resin was measured under the following GPC measurement conditions.

[GPC measurement conditions]

Measuring device: "HLC-8220 GPC" manufactured by Tosogabushiki Kaisha

Column: "ShodexKF802" manufactured by Showa Denko Co., Ltd.: 8.0mmФ×300mm

+ "ShodexKF802" manufactured by Showa Denko Co., Ltd.: 8.0mmФ×300mm

+ "ShodexKF803" manufactured by Showa Denko Co., Ltd.: 8.0mmФ×300mm

+ "ShodexKF804" manufactured by Showa Denko Co., Ltd.: 8.0mmФ×300mm

Column temperature: 40℃

Detector: RI (Differential Refractometer)

Data processing: "GPC-8020 Model II Version 4.30" manufactured by Dosogabushiki Kaisha

Developing solvent: tetrahydrofuran

Flow rate: 1.0mL/min

Sample: 0.5 mass% tetrahydrofuran solution in terms of resin solids, filtered through a microfilter

Injection volume: 0.1mL

Standard sample: Monodisperse polystyrene as follows:

(Standard sample: monodisperse polystyrene)

"A-500" manufactured by Dosogabushiki Kaisha

"A-2500" manufactured by Dosogabushiki Kaisha

"A-5000" manufactured by Dosogabushiki Kaisha

Dosogabushikigaisha "F-1"

Dosogabushiki Kaisha "F-2"

Dosogabushiki Kaisha "F-4"

Dosogabushiki Kaisha "F-10"

"F-20" by Dosogabushiki Kaisha

Synthesis Example 1 (Synthesis of novolac-type phenol resin (A-1))

In a 2000 mL four-necked flask equipped with a condenser, 164 g (1.52 mol) of m-cresol, 103 g (0.97 mol) of benzaldehyde, 74 g (0.61 mol) of salicylaldehyde, and 8 g of paratoluenesulfonic acid were charged, and the mixture was dissolved in 300 g of ethanol as a reaction solvent. Thereafter, the mixture was heated to 80°C with a mantle heater, and stirred under reflux for 16 hours to react. After the reaction, ethyl acetate and water were added, and the solution was separated and washed five times. The solvent was distilled off under reduced pressure from the remaining resin solution, and then dried under vacuum to obtain 281 g of a novolak-type phenol resin powder (A1) as a light red powder.

The Mw of the novolac-type phenol resin (A-1) was 3,100. The GPC chart of the novolac-type phenol resin (A-1) is shown in Fig. 1.

Synthesis Example 2 (Synthesis of novolac-type phenol resin (A-2))

Except that the input amounts of starting materials were 164 g (1.52 mol) of m-cresol, 80 g (0.75 mol) of benzaldehyde, and 92 g (0.75 mol) of salicylaldehyde, 280 g of powder of a novolac-type phenol resin (A-2) was obtained in the same manner as in Synthesis Example 1. The Mw of the novolac-type phenol resin (A-2) was 2,370.

The GPC chart of the novolac-type phenol resin (A-2) is shown in Fig. 2.

Synthesis Example 3 (Synthesis of novolac-type phenol resin (A-3))

Except that the input amounts of the starting materials were 164 g (1.52 mol) of m-cresol, 117 g (1.10 mol) of benzaldehyde, and 58 g (0.47 mol) of salicylaldehyde, 279 g of powder of a novolac-type phenol resin (A-3) was obtained in the same manner as in Synthesis Example 1. The Mw of the novolac-type phenol resin (A-3) was 2,700.

The GPC chart of the novolac-type phenol resin (A-3) is shown in Fig. 3.

Synthesis Example 4 (Synthesis of novolac-type phenol resin (A-4))

Except that the input amounts of the starting materials were 164 g (1.52 mol) of m-cresol, 67 g (0.63 mol) of benzaldehyde, and 115 g (0.94 mol) of salicylaldehyde, 282 g of powder of a novolac-type phenol resin (A-4) was obtained in the same manner as in Synthesis Example 1. The Mw of the novolac-type phenol resin (A-4) was 2,900.

The GPC chart of the novolac-type phenol resin (A-4) is shown in Fig. 4.

Synthesis Example 5 (Synthesis of novolac-type phenol resin (A-5))

Except that the reaction solvent was 250 g of ethanol, 30 g of 1-propanol, and 15 g of 2-propanol, 282 g of powder of a novolak-type phenol resin (A-5) was obtained in the same manner as in Synthesis Example 1. The Mw of the novolak-type phenol resin (A-5) was 3,200.

The GPC chart of the novolac-type phenol resin (A-5) is shown in Fig. 5.

Comparative Synthesis Example 1 (Synthesis of Novolac-type Phenol Resin (A-6))

Under a dry nitrogen stream, 140 g (1.30 mol) of m-cresol, 76 g (0.7 mol) of p-cresol, 151 g (1.86 mol) of a 37 wt% formaldehyde aqueous solution, and 1 g (0.01 mol) of oxalic acid dihydrate were placed in a 2000 mL 3-necked flask equipped with a condenser, and the mixture was dissolved in 528 g of methyl isobutyl ketone (MIBK), and the mixture was stirred and reacted for 4 hours while refluxing the reaction solution using a mantle heater. After the reaction, water was added, and separation and washing were performed five times. Methyl isobutyl ketone was distilled off under reduced pressure at 60°C using an evaporator, and then vacuum drying was performed to obtain 212 g of a pale red powder of phenol novolac resin (A-6). The Mw of phenol novolac resin (A-6) was 3,500.

Comparative Synthesis Example 2 (Synthesis of Novolac-type Phenol Resin (A-7))

Under a dry nitrogen stream, a 250 mL four-necked flask equipped with a condenser was charged with 100 g of a mixture of m-cresol and p-cresol in a weight ratio of 60:40, 11 g of tung oil (produced by Yamakei Sangyo Sha), and 0.01 g of p-toluenesulfonic acid, and stirred at 120°C for 2 hours to obtain compound (a-7), which is a drying oil-modified phenol derivative.

Next, 100 g of the compound (a-7), 13.9 g of paraformaldehyde, and 0.9 g of oxalic acid were mixed and stirred at 90°C for 3 hours to allow a reaction. Next, the temperature was increased to 120°C and stirred under reduced pressure for 3 hours, after which the reaction solution was cooled to room temperature under atmospheric pressure to obtain 102 g of a reaction product, a drying oil-modified phenol resin (A-7). The Mw of the phenol novolac resin (A-7) was 12,900.

[Positive photosensitive resin composition]

Example 1

1.00 g of phenol novolac resin (A-1) powder obtained in Synthesis Example 1, 0.15 g of photosensitive agent (1,2-naphthoquinone diazide (P-200: manufactured by Toyo Gosei Co., Ltd.)) powder (B), and 0.15 g of thermal cross-linking agent (methylated melamine resin (Nikalac MW-30HM: manufactured by Sanwa Chemical Co., Ltd.)) powder (C-1) were dissolved in 18 g of propylene glycol monomethyl ether acetate (D) to obtain a positive-type photosensitive resin composition (E-1).

Examples 2-5

Positive photosensitive resin compositions (E-2) to (E-5) were obtained in the same manner as in Example 1, except that the phenol novolac resin (A-2) to (A-5) powders shown in Table 1 were used as component (A).

Example 6

A positive photosensitive resin composition (E-6) was obtained in the same manner as in Example 1, except that a thermal cross-linking agent (methylated urea resin (Nikalac MX-270: manufactured by Sanwa Chemical Co., Ltd.)) powder (C-2) was used as the component (C).

Comparative examples 1~2

Positive photosensitive resin compositions (E-7) to (E-8) were obtained in the same manner as in Example 1, except that the phenol novolac resin (A-6) and (A-7) powder shown in Table 1 were used as component (A).

[evaluation]

A resist film was produced using a positive photosensitive resin composition prepared by examples and comparative examples, and the alkaline solubility, photosensitive agent affinity, low-temperature curing property, and low volume shrinkage property were evaluated.

(1) Alkaline solubility

A positive photosensitive resin composition was applied to a 5-inch silicon wafer with a spin coater to a thickness of about 1 ㎛, and dried on a hot plate at 110°C for 60 seconds. Thereafter, exposure was performed at 200 mJ/cm2 using a UV exposure device (UVE-1001SD, manufactured by San-Eidenki Seisakusho Co., Ltd.), and post-exposure baking (PEB) was performed on a hot plate at 130°C for 90 seconds after the exposure. The wafer with the obtained resist film attached was immersed in a developer (2.38% tetramethylammonium hydroxide (TMAH) aqueous solution) for 60 seconds, and then dried on a hot plate at 110°C for 60 seconds. The film thickness before and after immersion in the developer was measured, and the difference was divided by 60 to obtain the alkali solubility ADR1 (Å/s). The evaluation criteria are as follows.

○: ADR1 is 400 or higher

×: ADR1 is less than 400

The evaluation results are shown in Table 1. Also, the numbers in parentheses in Table 1 are the values of ADR1.

(2) Photosensitive affinity (development contrast)

In addition, in the above (1), the value measured without exposing the resist film was taken as ADR2 (Å/s), and the value of ADR1/ADR2 was evaluated as the photosensitizer affinity (developing contrast). The evaluation criteria are as follows.

○: Photosensitive affinity is 10 or higher

×: Photosensitive affinity less than 10

The evaluation results are shown in Table 1. Also, the numbers in parentheses in Table 1 are (ADR1/ADR2).

(3) Low temperature curing of resist film

A positive photosensitive resin composition was applied to a silicon wafer having a diameter of 5 inches using a spin coater to a thickness of about 10 ㎛, prebaked at 110° C. for 60 seconds, and then heat-treated (cured) at 175° C. for 1 hour in a nitrogen atmosphere. The wafer with the resist film attached was taken out at a point where the temperature became 50° C. or lower, and the film thickness was measured. Thereafter, the wafer with the resist film attached was divided into three parts, and each part was immersed in a solvent of acetone, N-methylpyrrolidone (NMP), and a 2.38 wt% TMAH aqueous solution for 15 minutes. After taking the wafer out of each solvent, the wafer was washed with pure water, and the film thickness was measured again.

The low-temperature curing ability was evaluated by the rate of change in film thickness before and after immersion in the solvent. The evaluation criteria are as follows.

○: Change rate is less than 5%

×: Change rate is 5% or more

The evaluation results are shown in Table 1. Also, the numbers in parentheses in Table 1 are the film thickness change rate (%).

(4) Volume shrinkage of resist film

A positive photosensitive resin composition was applied using a spin coater to a thickness of about 10 ㎛ on a silicon wafer having a diameter of 5 inches, and then prebaked at 110°C for 60 seconds. Thereafter, heat treatment (curing) was performed at 175°C for 1 hour in a nitrogen atmosphere. At a point where the temperature became 50°C or lower, the wafer with the resist film attached was taken out, and the shrinkage rate of the film thickness before and after curing was calculated using the calculation formula of [1-(film thickness after curing/film thickness before curing)] × 100, and the change rate was defined as the volume shrinkage. The evaluation criteria are as follows.

○: Change rate is less than 10%

×: Change rate is 10% or more

The evaluation results are shown in Table 1. Also, the figures in parentheses in Table 1 are volume shrinkage rates (%).

[Table 1]

In Table 1, the molar ratio of the structural units of component (A) “(a1)/(a2)/(a3)” is the molar ratio of the structural unit (a1) derived from m-cresol, the structural unit (a2) derived from benzaldehyde, and the structural unit (a3) derived from salicylaldehyde.

From Table 1, it can be confirmed that the resist film using the positive photosensitive resin composition of the present invention has alkaline solubility, high affinity for a photosensitive agent, and, when formed into a resist film, excellent low-temperature curing properties and low volume shrinkage properties.

Claims (9)

A positive photosensitive resin composition containing the following components (A) to (D).
(A) Novolac-type phenol resin having a molar ratio [(a1):(a2):(a3)] of a structural unit (a1) derived from m-cresol, a structural unit (a2) derived from benzaldehyde, and a structural unit (a3) derived from salicylaldehyde, of 1.0:0.3 to 0.8:0.3 to 0.8
(B) Photosensitive agent
(C) Thermal crosslinking agent
(D) Organic solvent In the first paragraph,
A positive photosensitive resin composition, wherein the above component (A) is a novolak-type phenol resin obtained by polycondensing m-cresol, benzaldehyde, and salicylaldehyde in an organic solvent in a molar ratio of m-cresol:benzaldehyde:salicylicaldehyde = 1.0:0.3 to 0.8:0.3 to 0.8 using an acid catalyst. In the first paragraph,
A positive photosensitive resin composition, wherein the total content of the structural unit (a1) derived from m-cresol, the structural unit (a2) derived from benzaldehyde, and the structural unit (a3) derived from salicylaldehyde in the above component (A) is 30 mass% or more. In the first paragraph,
A positive photosensitive resin composition, wherein the above component (B) is a quinonediazide-based photosensitive compound. In the first paragraph,
A positive photosensitive resin composition, wherein the above component (C) is a melamine resin or a urea resin. A photosensitive film obtained by drying the positive photosensitive resin composition according to any one of claims 1 to 5. A resist film obtained from a positive photosensitive resin composition according to any one of claims 1 to 5. A resist underlayer film obtained from a positive photosensitive resin composition according to any one of claims 1 to 5. A permanent resist film obtained from a positive photosensitive resin composition according to any one of claims 1 to 5.

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