JP2006251476A - Positive photosensitive polyimide precursor composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive photosensitive resin composition capable of forming a resin film which has a low thermal expansion coefficient, thereby suffering less from lowering of adhesion to a base material or warping of the base material and being free from deterioration in electrical characteristics, resolution or the like. <P>SOLUTION: The positive polyimide precursor composition contains a polyimide precursor having a benzoazole skeleton in the main chain while having a phenolic hydroxyl group in at least one out of a side chain and the main chain, and at least one kind selected from acid derivatives constructed by substitution of a hydrogen atom of a carboxyl group of cholic acid, deoxycholic acid, or lithocholic acid with a photo-elimination group selected from a group having a phenacyl structure and a group having a benzoynyl structure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a positive photosensitive polyimide precursor composition used for forming a semiconductor surface protective film and an interlayer insulating film for improving the reliability of a semiconductor element.

Conventionally, a polyimide resin having excellent heat resistance, electrical characteristics, and mechanical characteristics has been used for forming a surface protective film and an interlayer insulating film of a semiconductor element (see, for example, Non-Patent Document 1). In recent years, semiconductor devices have been highly integrated and increased in size so as to respond to improved productivity of major devices such as memories and microprocessors, and to support thin packaging of devices for information equipment. In addition, the sealing resin package has been made thinner and smaller, and the shift to surface mounting by solder reflow has further been promoted. Along with these circumstances, surface protection films and interlayer insulating films used for these materials have been required to have significant performance improvements such as heat cycle resistance and heat shock resistance, and higher performance polyimide resins are desired. It is rare.
“Latest Polyimide: Fundamentals and Applications,” issued by NTS, p. 327-338 (2002)

  Moreover, in order to simplify a circuit pattern manufacturing process, it has attracted attention that photosensitive polyimide is used.

In the case of using photosensitive polyimide in these applications, there are known negative types in which the exposed area is cured. However, in these negative types, there is a problem in safety in the development process, and in the development process, Since a solvent such as N-methylpyrrolidone which is environmentally unfavorable is used, a positive photosensitive polyimide resin which can be developed with an alkaline aqueous solution has been developed in recent years in place of the conventional negative type (for example, see Non-Patent Document 2). ). This positive photosensitive polyimide resin is particularly attracting attention because of its high heat resistance, excellent electrical properties, and high resolution. Moreover, photosensitive polybenzoxazole resin excellent in moisture resistance has been developed in place of the photosensitive polyimide resin (see, for example, Non-Patent Document 2).
“Latest Trends in Polymer Materials for Electronic Components III” published by Sumibe Techno Research, p. 88-119 (2001)

  However, conventional polyimide resins and polybenzoxazole resins have a problem that they have a larger thermal expansion coefficient than metals and inorganic materials.

  When the thermal expansion coefficient of the resin is large, if it is applied to a metal or inorganic material base material, cracks may occur in the film due to the thermal stress due to the difference in the thermal expansion coefficient, the film may peel off from the base material, Warpage occurs or the base material is destroyed. Furthermore, when lithography for patterning is performed in a state where a large warp is generated in the base material, the resolution of patterning deteriorates, which causes a problem. This problem is particularly serious when a large base material is used or when a thick coating is applied on the base material. Therefore, development of a positive photosensitive resin having a small thermal expansion coefficient is strongly desired. In particular, silicon wafers are important as a base material, but the thermal expansion coefficient is very small at 3 ppm / ° C, and the warpage of the wafer caused by the difference in thermal expansion from the resin is caused by defective products in the manufacturing process, defective transport, cracks. This is not preferable in view of the cause of this or the influence on the device characteristics.

  The present invention was made to alleviate problems such as a decrease in adhesion to a base material and warping of the base material due to the large thermal expansion coefficient of conventional positive photosensitive resins. A positive type photosensitive resin that has a low expansion coefficient, and therefore can reduce resin adhesion and warpage of the substrate, and can provide a resin film that does not deteriorate electrical characteristics, resolution, etc. It aims at providing a conductive resin composition.

  The present invention relates to a polyimide precursor having a benzoazole skeleton such as benzoxazole in the main chain and containing at least one of a carboxyl group and a phenolic hydroxyl group in at least one of the main chain and the side chain, and cholic acid or deoxy Contains at least one selected from acid derivatives constituted by substituting a hydrogen atom of a carboxyl group of cholic acid or lithocholic acid with a photoleaving group selected from a group having a phenacyl structure and a group having a benzoinyl structure To achieve the above object.

  In other words, the present invention includes a polyimide precursor represented by the general formula (1),

(In the formula, R ¹ represents a tetravalent organic group optionally having a phenolic hydroxyl group, R ² represents a hydroxyl group, an organic group containing a phenolic hydroxyl group, or other monovalent organic group; ³ represents general formulas (2) to (5), and

(In the general formulas (2) to (5), X represents an oxygen atom, a sulfur atom or NR ⁸ (wherein R ⁸ represents a hydrogen atom alkyl group or a phenyl group), and R ⁴ and R ⁶ are each independently selected. An aromatic ring group or a heterocyclic group composed of a single ring or a plurality of rings which may have a phenolic hydroxyl group, and R ⁵ and R ⁷ each independently have a phenolic hydroxyl group. An aromatic ring group, a heterocyclic group or an aliphatic ring group composed of a single ring or a plurality of rings which may be
An acid derivative constituted by substituting a hydrogen atom of a carboxyl group of cholic acid, deoxycholic acid, and / or lithocholic acid with a photolabile group selected from a group having a phenacyl structure and a group having a benzoinyl structure; It is a positive photosensitive polyimide precursor composition characterized by containing.

  In the positive photosensitive polyimide precursor composition having the above-described configuration, the total amount of carboxyl groups and phenolic hydroxyl groups contained in the whole polyimide precursor is 0.3 to 1 per mole of the repeating unit represented by the general formula (1). 3 moles are preferred.

  At least one terminal of the polyimide precursor is blocked through the binding group by a chain extender having a binding group that binds to an aromatic diamine or dianhydride. It further has a linking group for linking the polyimide precursors via the chain extender under conditions different from the conditions for forming a polyimide precursor from an aromatic diamine and a dianhydride. preferable.

  The positive photosensitive polyimide precursor composition of the present invention has a small difference in thermal expansion coefficient between the polyimide obtained after coating and thermal cyclization on a low thermal expansion coefficient substrate such as a silicon wafer, and In addition, the adhesion between the polyimide and the base material is good, the warpage and the like can be reduced, and the developability and photosensitivity can be maintained well. As a result, a good pattern can be obtained.

  Hereinafter, the present invention will be described in detail.

  The positive photosensitive polyimide precursor composition of the present invention has a benzoazole skeleton such as benzoxazole in the main chain, and contains at least one of a carboxyl group and a phenolic hydroxyl group in at least one of the main chain and the side chain And a hydrogen precursor of a carboxyl group of cholic acid, deoxycholic acid or lithocholic acid is substituted with a photoleaving group selected from a group having a phenacyl structure and a group having a benzoinyl structure It contains at least one selected from acid derivatives.

  The polyimide precursor relating to the present invention preferably comprises a structural unit represented by the general formula (1) as a main component, and can be a resin having an imide ring by heating or adding an appropriate catalyst. Thus, polyimide having excellent heat resistance is formed by imide ring formation.

In the formula (1), R ¹ represents a tetravalent organic group that may contain a phenolic hydroxyl group, R ² represents a hydroxyl group, an organic group containing a phenolic hydroxyl group, or other monovalent organic group. Represents.

In the general formula (1), R ¹ is not particularly limited as long as it is a tetravalent organic group, but in order to give heat resistance to the polyimide, the aromatic ring group or aromatic heterocycle having 6 to 30 carbon atoms. A group having a group is preferred. Preferred examples of R ¹ include pyromellitic acid, naphthalenetetracarboxylic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-diphenylethertetracarboxylic acid, 3, Tetracarboxylic such as 3 ′, 4,4′-diphenylhexafluoropropanetetracarboxylic acid, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, etc. Examples include acid-derived structures. R ¹ may be an aromatic ring group or aromatic heterocycle containing a phenolic hydroxyl group. Examples of such an aromatic ring group or aromatic heterocycle include bis (3-amino-4 -Hydroxyphenyl) propane, bis (3-amino-4-hydroxyphenyl) hexafluoropropane, bis (3-hydroxy-4-aminophenyl) propane, bis (3-amino-4-hydroxyphenyl) sulfone, bis (3 -Amino-4-hydroxyphenyl) ether, 3,3'-diamino-4,4'-dihydroxybiphenyl and other diamines and 2-fold moles of pyromellitic anhydride reacted with R ¹ corresponding part Etc.

In the general formula (1), R ² is a hydroxyl group, an organic group containing a phenolic hydroxyl group, or another monovalent organic group, and is introduced into the polyimide precursor structure by a covalent bond. The organic group having a phenolic hydroxyl group or other monovalent organic group is not particularly limited as long as it can be introduced into the polyimide precursor by a covalent bond. In consideration of easiness, wide selection when considering the group that can be introduced, and ease of elimination during imide ring formation, those derived from alcohol compounds or those derived from amine compounds are preferred. If it is these, it introduce | transduces into a polyimide precursor by either synthesize | combining an ester body using an alcohol compound by a well-known method, or synthesize | combining an amide body using an amine compound.

Examples of the organic group containing a phenolic hydroxyl group represented by R ² include a hydroxybenzyloxy group and a hydroxyphenethyloxy group. Examples of the alcohol compound having a phenolic hydroxyl group used for introducing an organic group containing a phenolic hydroxyl group by an ester bond include 4-hydroxybenzyl alcohol, 3-hydroxybenzyl alcohol, 2-hydroxybenzyl alcohol. 4-hydroxyphenethyl alcohol and the like. Examples of the amine compound containing a phenolic hydroxyl group include 4-hydroxybenzylamine, 3-hydroxybenzylamine, 2-hydroxybenzylamine, 4-hydroxyphenethylamine, and the like.

In addition, the other monovalent organic group represented by R ² is not particularly limited as long as it does not have a phenolic hydroxyl group, and examples thereof include an alkyl group having 1 to 10 carbon atoms, an alkoxy group, and an alkylamino group. Examples thereof include a phenyl group having 6 to 10 carbon atoms, a phenoxy group, a phenylamino group, a benzyl group, and the like.

  In general, in order to reduce the thermal expansion coefficient of polyimide, it is considered that the polyimide main chain needs to have a rigid and straight rod-like structure in terms of chemical structure. In order to form such a rigid and straight rod-like structure, a para bond of a ring structure is particularly important. This is because in such a polyimide having a ring structure having a para bond, the in-plane orientation degree of the polyimide skeleton is increased, and therefore, it is considered that the polyimide skeleton has a rigid and straight rod-like structure.

The polyimide precursor according to the present invention has a benzoazole skeleton such as benzoxazole in the main chain as a chemical structure suitable for reducing the thermal expansion coefficient of such polyimide. In the general formula (1), , R ³ has a benzoazole skeleton represented by any one of the following general formulas (2) to (5).

(In the general formulas (2) to (5), X represents an oxygen atom, a sulfur atom or NR ⁸ (wherein R ⁸ represents a hydrogen atom, an alkyl group or a phenyl group), and R ⁴ and R ⁶ each represents Independently, it represents an aromatic ring group or a heterocyclic group composed of a single ring or a plurality of rings which may have a phenolic hydroxyl group, and R ⁵ and R ⁷ each independently represent a phenolic hydroxyl group. It represents an aromatic ring group, a heterocyclic group or an aliphatic ring group composed of a single ring or a plurality of rings which may have.

The aromatic group or heterocyclic group which may have a phenolic hydroxyl group represented by R ^{4 in the} formulas (2) to (3) includes ^four aromatic groups or heterocyclic compounds which may have a phenolic hydroxyl group. It is a tetravalent group corresponding to that excluding hydrogen. As specific examples of the aromatic group or heterocyclic group which may have a phenolic hydroxyl group represented by R ^{4 in the} formulas (2) to (3),

(Wherein, X ⁴ represents an oxygen atom, a sulfur atom, SO ₂ , S═O, CH ₂ , C═O, hexafluoroisopropylidene, isopropylidene), and the like. Any hydrogen atom may be substituted with a hydroxyl group.

The aromatic group or heterocyclic group which may have a phenolic hydroxyl group represented by R ^{5 in the} formulas (2) to (4) includes two aromatic groups or heterocyclic compounds which may have a phenolic hydroxyl group. It is a divalent group corresponding to that obtained by removing hydrogen. As specific examples of the aromatic group or heterocyclic group represented by R ^{5 in the} formulas (2) to (4),

(Wherein, X ⁵ is an oxygen atom, a sulfur atom, SO ₂ , S═O, CH ₂ , C═O, hexafluoroisopropylidene, isopropylidene), and the like. Any hydrogen atom may be substituted with a hydroxyl group. Moreover, a cyclohexylene group is mentioned as an example of group which has an aliphatic ring.

The aromatic group or heterocyclic group which may have a phenolic hydroxyl group represented by R ^{6 in the} formulas (4) to (5) is composed of three aromatic compounds or heterocyclic compounds which may have a phenolic hydroxyl group. It is a trivalent group corresponding to that obtained by removing hydrogen. As specific examples of the aromatic group or heterocyclic group represented by R ^{6 in the} formulas (4) to (5),

(Wherein, X ⁶ is an oxygen atom, a sulfur atom, SO ₂ , S═O, CH ₂ , C═O, hexafluoroisopropylidene, isopropylidene), and the like. Any hydrogen atom may be substituted with a hydroxyl group.

The aromatic group or heterocyclic group which may have a phenolic hydroxyl group represented by R ^{7 in} Formula (5) is obtained by removing two hydrogens from an aromatic compound or heterocyclic compound which may have a phenolic hydroxyl group. It is a divalent group corresponding to the above. Specific examples of the aromatic group or heterocyclic group represented by R ^{7 in the} formula (5) include

(Wherein X ⁷ is an oxygen atom, a sulfur atom, SO ₂ , S═O, CH ₂ , C═O, hexafluoroisopropylidene or isopropylidene), and the aromatic ring Any hydrogen atom may be substituted with a hydroxyl group. Moreover, a cyclohexylene group is mentioned as an example of group which has an aliphatic ring.

The bonding position for forming the main chain of R ^{4 to} R ⁷ may be arbitrary. However, in order to give the formed polyimide a linear shape, it is bonded at the para position or in the ring structure as described above. It is preferable to combine them so that the positional relationship is as far as possible.

Preferable specific examples of the R ³ group represented by any one of R ^{4 to} R ⁷ as described above include 2,6- (4,4′-diaminodiphenyl) benzo [1,2-d: 5,4 -D '] bisoxazole, 5-amino-2- (p-aminophenyl) -benzoxazole, 5-amino-2- (m-aminophenyl) -benzoxazole, 4,4'-diphenyl ether-2,2' -Bis (5-aminobenzoxazole), 2,2'-p-phenylenebis (5-aminobenzoxazole), 2,2'-bis (4-phenyl) hexafluoropropane-2,2 '-(5- Diaminobenzoxazole residues such as aminobenzoxazole), 2,6- (4,4′-diaminodiphenyl) benzo [1,2-d: 5,4-d ′] bisthiazole, 5-amino-2- ( p-amino Diaminobenzothiazole residues such as phenyl) -benzothiazole, 5-amino-2- (m-aminophenyl) -benzothiazole, 2,2′-p-phenylenebis (5-aminobenzothiazole), 2,6- (4,4′-diaminodiphenyl) benz [1,2-d: 5,4-d ′] bisimidazole, 5-amino-2- (p-aminophenyl) -benzimidazole, 5-amino-2- ( Examples include residues of diaminobenzimidazole such as m-aminophenyl) -benzimidazole and 2,2′-p-phenylenebis (5-aminobenzimidazole). Examples of those having a phenolic hydroxyl group include 5-amino-2- (m-hydroxy-p-aminophenyl) -benzoxazole and 5-amino-2- (m-amino-p-hydroxyphenyl) -benzoxazole. Diaminobenzoxazole residues such as 4,4′-di (m-hydroxyphenyl) ether-2,2′-bis (5-aminobenzoxazole), 2,6- (3,3′-dihydroxy-4, 4′-diaminodiphenyl) benzo [1,2-d: 5,4-d ′] bisthiazole, 5-amino-2- (m-hydroxy-p-aminophenyl) -benzothiazole, 5-amino-2- Diaminobenzothiazole residues such as (m-amino-p-hydroxyphenyl) -benzothiazole, 2,6- (3,3′-dihydroxy-4,4′-diamidine Nodiphenyl) benz [1,2-d: 5,4-d ′] bisimidazole, 5-amino-2- (m-hydroxy-p-aminophenyl) -benzimidazole, 5-amino-2- (m- And diaminobenzimidazole residues such as amino-p-hydroxyphenyl) -benzimidazole.

  In the polyimide precursor having the above structure, the total amount of carboxyl groups and phenolic hydroxyl groups contained in the entire polyimide precursor is 0.3 to 3 mol per 1 mol of the repeating unit represented by the general formula (1). preferable. When the total amount of the carboxyl group and the phenolic hydroxyl group is too small, there is a possibility that sufficient solubility in an alkali developer may not be exhibited, and a good positive photosensitive function may not be exhibited. If the amount is too large, the film is greatly reduced during development, and a good pattern cannot be formed.

In order to improve the adhesion to the substrate, an aliphatic group having a siloxane structure may be copolymerized in R ¹ and R ³ within a range that does not lower the heat resistance. Specific examples of the diamine component include those obtained by copolymerizing 1 to 10 mol% of bis (3-aminopropyl) tetramethyldisiloxane.

  Further, in the present invention, the polyimide precursor is used under conditions different from those for forming a polyimide precursor from an aromatic diamine and a dianhydride and a binding group that binds to an aromatic diamine or dianhydride. It is preferable that at least one end of the polyimide precursor is blocked via a binding group by a chain extender having two types of functional groups with a linking group for linking the bodies. When the polyimide precursor is blocked by such a chain extender, after forming the polyimide precursor from the aromatic diamine and dianhydride, using a linking group under different conditions from the precursor formation. The molecular weight of the polyimide precursor can be increased. This increase in molecular weight can be arbitrarily controlled by adjusting the amount of chain extender added.

  The chain extender used in the present invention is not particularly limited, and examples thereof include a dianhydride or a primary or secondary amine containing an alkenyl group, an alkynyl group or a cyclobutene ring. Specifically, maleic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, vinylphthalic anhydride, 1,2-dimethylmaleic anhydride, 4-cyclohexene-1,2-dicarboxylic anhydride, 2,3,6-tetradrophthalic anhydride, phenylethynylaniline, ethynylaniline, 3- (3-phenylethynylphenoxy) aniline, propargylamine, aminobenzocyclobutene and the like. In general, the greater the amount of chain extender added, the lower the molecular weight of the polyimide precursor and hence the viscosity of the solution containing it. There is also an optimum solution viscosity depending on the coating method. Therefore, the concentration of the chain extender and the coating method are selected in consideration of obtaining the desired molecular weight and solution viscosity.

The polyimide precursor used in the present invention is synthesized by reacting tetracarboxylic dianhydride and diaminobenzoazole. When introducing a phenolic hydroxyl group, the main chain has a phenolic hydroxyl group. Select at least one of tetracarboxylic dianhydride and diaminobenzoxazole to contain a phenolic hydroxyl group, or a group having a phenolic hydroxyl group as R ² so that the side chain has a phenolic hydroxyl group as R ² Introduce. When a group having a phenolic hydroxyl group is introduced as R ² , a method of reacting an alcohol compound or an amine compound is known, and this method will be described as an example. First, tetracarboxylic dianhydride is reacted with an alcohol compound or an amine compound to synthesize a tetracarboxylic acid diester or tetracarboxylic acid diamide, and then the diester or diamide is reacted with a chlorinating agent such as thionyl chloride. Then, tetracarboxylic acid diester chloride or tetracarboxylic acid diamide chloride is synthesized. Thereafter, the obtained chloride is dissolved in an organic solvent and reacted with diaminobenzoxazole dissolved in an organic solvent containing a dehydrohalogenating agent such as pyridine, or cyclohexylcarbodiimide, diphenyl (2,3-dihydro). Reaction with diaminobenzoxazole using a suitable dehydrating agent such as -thioxo-3-benzoxazole) phosphonate. As the solvent at this time, polar solvents mainly composed of N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphorotriamide, and γ-butyrolactone are used. Examples include a solvent having a main component.

  The positive photosensitive polyimide precursor composition of the present invention includes, in addition to the polyimide precursor, a hydrogen atom of a carboxyl group of cholic acid, deoxycholic acid or lithocholic acid, a group having a phenacyl structure and a group having a benzoinyl structure. At least one selected from acid derivatives substituted with a photolabile group selected from:

  Specific examples of the group having a phenacyl structure constituting the photoleaving group of the acid derivative include an α-methylphenacyl group, an α-methyl-4-nitrophenacyl group, an α-phenylphenacyl group, 4 Examples include -methoxyphenacyl group, α- (2,4-dichlorophenyl) phenacyl group, α-n-butylphenacyl group, α- (3-methoxyphenyl) -4-chlorophenacyl group. Further, examples of the benzoinyl group constituting the photolabile group of the acid derivative include 3′-methoxybenzoinyl group, 3 ′, 5′-dimethoxybenzoinyl group, 3,3 ′, 4,4′-dimethyl. Examples include a rangeoxybenzoinyl group and a 2,2 ′, 3,3′-tetramethoxybenzoinyl group.

  The acid derivative as described above can be synthesized by a known method. For example, after reacting cholic acid, deoxycholic acid or lithocholic acid with thionyl chloride to change it to an acid chloride derivative, alcohols that become photoleaving groups such as phenacyl alcohol and benzoinyl alcohol are added thereto. It is obtained by reacting. As another method, a method of reacting a halogenated compound of a compound that becomes a photolabile group such as a phenacyl bromide derivative with cholic acid, deoxycholic acid, or lithocholic acid.

  A part or all of the hydroxyl groups of each of cholic acid, deoxycholic acid, or lithocholic acid constituting the acid derivative may be protected with a substituent. Preferred substituents for protecting the hydroxyl group include a lower alkylcarbonyl group such as a methylcarbonyl group and a lower haloalkylcarbonyl group such as a trihalomethylcarbonyl group (for example, a trifluoromethylcarbonyl group). Specifically, an acetyl group, a trifluoroacetyl group, and the like are preferable.

  The acid derivative is preferably added in an amount of 2 to 100 parts by mass, more preferably 5 to 50 parts by mass with respect to 100 parts by mass of the resin precursor.

  In the positive photosensitive polyimide precursor composition of the present invention, an adhesion promoter is used in order to improve the adhesion between the coating film of the composition of the present invention or the polyimide film after the heat treatment and the substrate. Can do.

  As the adhesion promoter, an organic silane compound, an aluminum chelate compound, a titanium chelate compound, a silicon-containing polyamic acid, and the like are preferable. Further, other additives may be added as long as adhesion to the substrate, sensitivity, resolution, heat resistance and the like are not impaired.

  The positive photosensitive polyimide precursor composition of the present invention can be obtained in a solution state by dissolving in a solvent. As the solvent, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphorotriamide, γ-butyrolactone and the like can be used.

The photosensitive polyimide precursor composition of the present invention is applied to the surface of a substrate such as a silicon wafer, a metal substrate, or a ceramic substrate by a dipping method, a spray method, a screen printing method, a spin coating method, etc. By removing the portion, a non-sticky coating film can be provided on the substrate surface. Although there is no restriction | limiting in particular in the thickness of a coating film, it is preferable that it is 4-50 micrometers.

  This coating film is irradiated with actinic rays such as ultraviolet rays, visible rays, X-rays, and electron beams through a mask having a predetermined pattern. After exposure to a pattern, the exposed portion of the film is developed with an appropriate developer. Thus, a desired patterned film can be obtained.

  Actinic radiation irradiation equipment can irradiate g-line stepper, i-line stepper, contact / proximity exposure machine using ultra-high pressure mercury lamp, mirror projection exposure machine, or other ultraviolet rays, visible rays, X-rays, electron beams Projectors and radiation sources can be used.

  Developers include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine, and di-n. Secondary amines such as propylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as diethanolamine and triethanolamine, quaternary ammonium salt alkalis such as tetramethylammonium hydroxide and tetraethylammonium hydroxide Aqueous aqueous solutions and aqueous solutions in which appropriate amounts of water-soluble organic solvents and surfactants such as alcohols such as methanol and ethanol are added thereto can be suitably used.

  After the development, it is desirable that the pattern be stabilized by washing with water or a poor solvent, if necessary, and then drying at about 100 ° C. By heating the film on which the pattern is formed, a film having excellent heat resistance, mechanical properties, and electrical properties can be obtained.

  The heating temperature is preferably 150 to 500 ° C, more preferably 300 to 450 ° C. The heating time is preferably 0.05 to 10 hours. The heat treatment is usually performed while raising the temperature stepwise or continuously.

(Function)
The present invention provides a positive photosensitive polyimide precursor composition capable of obtaining a polyimide having a small thermal expansion coefficient after curing. A polyimide precursor having a benzoazole skeleton such as benzoxazole in the main chain and containing at least one of a carboxyl group and a phenolic hydroxyl group in the main chain or side chain, and a carboxyl group of cholic acid, deoxycholic acid or lithocholic acid Positive-type photosensitivity by containing at least one selected from acid derivatives constituted by substituting the hydrogen atom of 1 with a photolabile group selected from a group having a phenacyl structure and a group having a benzoinyl structure It is based on the fact that the thermal expansion coefficient of polyimide obtained by curing can be reduced by using it as a polyimide precursor and having a benzoazole skeleton. An acid derivative formed by substituting the hydrogen atom of the carboxyl group of cholic acid, deoxycholic acid or lithocholic acid with a photoleaving group is decomposed by exposure to the photoeliminating group of the acid derivative, resulting in cholic acid or deoxy By changing to cholic acid or lithocholic acid, the solubility of the exposed portion in an alkaline aqueous solution is improved, and the resin precursor itself also exhibits alkali solubility, so that only the exposed portion is removed under alkaline conditions to function as a positive type. Therefore, a resin film having high exposure sensitivity, good pattern formability, and excellent heat resistance can be obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

(Synthesis Example 1)
In a 300 ml three-necked separable flask equipped with a stirrer and a condenser, 100 ml of N-methylpyrrolidone (also referred to as NMP) and 20.54 g (60 mmol) of 2,6- (4,4′diaminodiphenyl) -benzo [1 , 2-d: 5,4-d ′] bisoxazole (diamine 1) is added to form a suspension, and the flask is gently purged with nitrogen for 30 minutes. The reaction system was ice-cooled (5 ° C. or lower), and 12.04 g (55.205 mmol) of pyromellitic dianhydride (also referred to as PMDA) and 0.95 g (9.6 mmol) of maleic anhydride were added. Was stirred for about 68 hours to obtain a polyimide precursor 1.

(Synthesis Example 2)
Applying the technique of Synthesis Example 1, 100 ml of NMP, 13.52 g (60 mmol) of 5-amino-2- (p-aminophenyl) -benzoxazole (diamine 2), 0.95 g (9.6 mmol) of Maleic anhydride and 12.04 g (55.205 mmol) of pyromellitic dianhydride (PMDA) were reacted at room temperature for 45 hours to obtain polyimide precursor 2.

(Synthesis Example 3)
Applying the technique of Synthesis Example 1, 100 ml of NMP, 13.52 g (60 mmol) of 5-amino-2- (p-aminophenyl) -benzoxazole (diamine 2), 0.95 g (9.6 mmol) of Maleic anhydride and 16.25 g (55.205 mmol) of 3,3′4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) were reacted at room temperature for 45 hours to obtain polyimide precursor 3.

(Synthesis Example 4)
Applying the technique of Synthesis Example 1, 100 ml of NMP, 14.46 g (60 mmol) of 5-amino-2- (p-aminophenyl) -benzothiazole (diamine 3), 0.95 g (9.6 mmol) of Maleic anhydride and 12.04 g (55.205 mmol) of pyromellitic dianhydride (PMDA) were reacted at room temperature for 45 hours to obtain polyimide precursor 4.

(Synthesis Example 5)
Applying the technique of Synthesis Example 1, 100 ml of NMP, 13.56 g (60 mmol) of 5-amino-2- (p-aminophenyl) -benzimidazole (diamine 4), 0.95 g (9.6 mmol) of Maleic anhydride and 12.04 g (55.205 mmol) of pyromellitic dianhydride (PMDA) were reacted at room temperature for 45 hours to obtain polyimide precursor 5.

(Synthesis Example 6)
Applying the technique of Synthesis Example 1, 100 ml of NMP, 13.86 g (60 mmol) of 5-amino-2- (4-aminocyclohexyl) -benzoxazole (diamine 5), 95 g (9.6 mmol) of anhydrous male An acid and 12.04 g (55.205 mmol) of pyromellitic dianhydride (PMDA) were reacted at room temperature for 45 hours to obtain polyimide precursor 6.

(Synthesis Example 7)
Applying the technique of Synthesis Example 1, 100 ml of NMP, 13.86 g (60 mmol) of 5-amino-2- (4-aminocyclohexyl) -benzoxazole (diamine 5), 95 g (9.6 mmol) of anhydrous male An acid and 12.37 g (55.205 mmol) of 1,2,3,4-cyclohexanetetracarboxylic dianhydride (also referred to as H-PMDA) were reacted at room temperature for 45 hours to obtain polyimide precursor 7.

(Synthesis Example 8)
To flask 1 equipped with a nitrogen inlet tube, 1 mol of pyromellitic anhydride (PMDA), 1 mol of 4-hydroxybenzyl alcohol and 2 L of NMP were added and stirred, followed by 1 mol of triethylamine over 30 minutes. It was dripped. After dropping, the mixture was left in this state for 3 hours, and 1 mol of 5-amino-2- (p-aminophenyl) -benzoxazole (diamine 2)) was added after completion of the reaction. Next, 2.1 mol of diphenyl (2,3-dihydro-thioxo-3-benzoxazole) phosphonate was added in five portions, and after the addition, the mixture was condensed in that state for 5 hours. In addition, 2 mol of maleic anhydride, 2.1 mol of 4-hydroxybenzyl alcohol and 1 L of NMP were added to the flask 2 equipped with another nitrogen introduction tube and stirred, followed by 2.1 mol of triethylamine. Was added dropwise over 30 minutes. After dropping, the solution was allowed to stand in this state for 3 hours, and then the solution in flask 2 was mixed with flask 1 and stirred for 30 minutes. Next, 2.1 mol of diphenyl (2,3-dihydro-thioxo-3-benzoxazole) phosphonate was added in five portions, and after the addition, the mixture was condensed in that state for 5 hours. The obtained slurry-like mixture was poured into a large amount of methanol and washed, and the obtained solid resin was dried for 12 hours by a vacuum dryer, whereby a polyimide precursor 8 was obtained.

(Synthesis Example 9)
Applying the technique of Synthesis Example 1, 100 ml of NMP, 12.01 g (60 mmol) of 4,4′diaminodiphenyl ether (diamine 6), 0.95 g (9.6 mmol) of maleic anhydride and 12.04 g ( 55.205 mmol) of pyromellitic dianhydride (PMDA) was reacted at room temperature for 45 hours to obtain a polyimide precursor 9.

(Synthesis Example 10)
Applying the technique of Synthesis Example 1, 100 ml of NMP, 19.90 g (60 mmol) of 4,4′-diaminodiphenylsulfone (diamine 7), 0.95 g (9.6 mmol) of maleic anhydride and 12.04 g (55.205 mmol) of pyromellitic dianhydride (PMDA) was reacted at room temperature for 45 hours to obtain a polyimide precursor 10.

(Synthesis of acid derivatives)
20 ml of N, N-dimethylformamide was placed in a 300 ml eggplant flask, and 15 mmol of cholic acid was gradually added and dissolved while stirring. Further, 15 mmol of triethylamine was added, and the mixture was cooled with ice and stirred. Next, 13.5 mmol of α-methylphenacyl bromide was added and dissolved, allowed to stand at 5 ° C. for 2 days, 150 ml of water was added, and the precipitated solid was washed with water and dried. Further, α-methylphenacyl cholic acid (hereinafter referred to as acid derivative 1) was obtained by recrystallization with ethyl alcohol.

  Similarly, 3 ′, 5′-dimethoxybenzoinylcholic acid (acid derivative 2), α-methylphenacyldeoxycholic acid (acid derivative 3), and α-methylphenacyllithocholic acid (acid derivative 4) were obtained. .

Example 1
100 parts by mass of the polyimide precursor obtained in Synthesis Example 1 and 25 parts by mass of the acid derivative 1 of the acid derivative synthesis example were dissolved in NMP to obtain a photosensitive varnish. The obtained varnish was spin-coated on a silicon wafer with a spin coater and dried at 100 ° C. for 5 minutes using a hot plate to obtain a 10 μm coating film. This coating film was irradiated with ultraviolet rays using a super high pressure mercury lamp through a mask (a 1-50 μm remaining pattern and a removal pattern). Then, it was developed with a 2.38% aqueous tetramethylammonium hydroxide solution. It was then rinsed with water and dried. As a result, a good pattern was formed by irradiation with an exposure dose of 450 mJ / cm ² , and the residual film ratio was 93%. The appearance after development was also good. Furthermore, heat treatment was performed at 200 ° C. for 30 minutes and at 400 ° C. for 60 minutes in a nitrogen atmosphere. The coefficient of thermal expansion is obtained from a plot of the coefficient of linear expansion obtained by measuring the coefficient of linear expansion when the sample is heated in an appropriate temperature range. Examples of the method for measuring the linear expansion coefficient include TMA (thermomechanical analysis) method, direct reading method, optical interference method, push rod method, capacitance method, SQUID method, etc. In Example 1, the film after heat treatment is made of silicon. It was peeled from the wafer and measured at a rate of temperature increase of 10 ° C./min in the range of 25 to 200 ° C. by the TMA (thermomechanical analysis) method. As a result, it was confirmed that the resin had a low thermal expansion coefficient of 6 ppm / ° C. .

(Examples 2 to 8)
A photosensitive varnish was prepared in the same manner as in Example 1 except that the polyimide precursors 2 to 8 of Synthesis Examples 2 to 8 were used instead of the polyimide precursor of Synthesis Example 1 used in Example 1. Evaluation was conducted in the same manner as in Example 1.

(Examples 9 to 11)
A photosensitive varnish was prepared in the same manner as in Example 1 except that acid derivatives 2 to 3 were used instead of the acid derivative 1 used in Example 1, and evaluated in the same manner as in Example 1.

(Comparative Examples 1-2)
A photosensitive varnish was prepared in the same manner as in Example 1 except that the polyimide precursors 9 to 10 of Synthesis Examples 9 to 10 were used instead of the polyimide precursor 1 of Synthesis Example 1 used in Example 6. In the same manner as in Example 1, the evaluation was made.

(Comparative Example 3)
A photosensitive varnish was prepared in the same manner as in Example 1 except that MG-300 (manufactured by Toyo Gosei Kogyo Co., Ltd.), which is a naphthoquinone diazide compound, was used instead of the ester 1 used in Example 1. In the same manner as in Example 1, the evaluation was made.

The evaluation results of Examples 1 to 11 and Comparative Examples 1 to 3 are shown in Table 1 below. In Table 1, “sensitivity” is the amount of exposure required for pattern formation with a resolution of 10 μm, and the appearance evaluation of the film after development is such that there is no residual development in the exposed area and the pattern edge is smooth. Rated as “good”. The remaining film rate was calculated and calculated by the following method.
Residual film ratio (%) = {(film thickness of unexposed part after development) / (film thickness of unexposed part before development)} × 100

  According to the results shown in Table 1 above, the present invention shown in Examples 1 to 11 is clearly shown by comparing the thermal expansion coefficients of Examples 1 to 11 with those of Comparative Examples 1 and 2. Compared with the conventional polyimide (Comparative Examples 1-2), the thermal expansion coefficient of the polyimide obtained from the positive photosensitive polyimide precursor composition is clearly reduced. Moreover, when the sensitivity in Example 1-11 and the comparative example 3 and a residual film rate and the external appearance after image development are compared, it turns out that all are excellent.

  The positive photosensitive polyimide precursor composition of the present invention is used as an electrical and electronic insulating material in the manufacture of semiconductor devices and the like, and specifically, used as a surface protective film, an interlayer insulating film, etc. of semiconductor elements such as IC and LSI. It can be used for those that require fine pattern processing.

Claims (3)

A polyimide precursor represented by the general formula (1);

(In the formula, R ¹ represents a tetravalent organic group optionally having a phenolic hydroxyl group, R ² represents a hydroxyl group, an organic group containing a phenolic hydroxyl group, or other monovalent organic group; ³ represents general formulas (2) to (5), and

(In the general formulas (2) to (5), X represents an oxygen atom, a sulfur atom or NR ⁸ (wherein R ⁸ represents a hydrogen atom alkyl group or a phenyl group), and R ⁴ and R ⁶ are each independently selected. An aromatic ring group or a heterocyclic group composed of a single ring or a plurality of rings which may have a phenolic hydroxyl group, and R ⁵ and R ⁷ each independently have a phenolic hydroxyl group. An aromatic ring group, a heterocyclic group or an aliphatic ring group composed of a single ring or a plurality of rings which may be
Selected from acid derivatives constructed by substituting the hydrogen atom of the carboxyl group of cholic acid, deoxycholic acid, and / or lithocholic acid with a photoleaving group selected from a group having a phenacyl structure and a group having a benzoinyl structure A positive-type photosensitive polyimide precursor composition comprising:   The total amount of carboxyl groups and phenolic hydroxyl groups of the polyimide precursor having the structure represented by the general formula (1) in the repeating unit is 0.3 to 3 per mole of the repeating unit represented by the general formula (1). The positive photosensitive polyimide precursor composition of Claim 1 which is a mole.   At least one terminal of the polyimide precursor is blocked through the binding group by a chain extender having a binding group that binds to an aromatic diamine or dianhydride. Further comprising a linking group for linking the polyimide precursors via the chain extender under conditions different from the conditions for forming a polyimide precursor from an aromatic diamine and a dianhydride, Item 3. The positive photosensitive polyimide precursor composition according to any one of Items 1 and 2.