JP2005345537A - Positive photosensitive polyimide precursor composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive photosensitive resin precursor composition, in which the coefficient of thermal expansion is small and therefore, decrease in adhesiveness with a substrate, warpage of the substrate or the like are prevented to be able to form a resin film which is prevented from deterioration in electrical characteristics, resolution or the like. <P>SOLUTION: The positive polyimide precursor composition comprises a polyimide precursor containing a benzoxazole skeleton in the main chain and an OR group in at least either the main chain or a side chain (wherein R represents a monovalent organic group which can be decomposed due to the effect of an acid and converted into hydrogen); and a photo-acid generating agent. Since the positive polyimide precursor composition has a small coefficient of thermal expansion after polyimidization, the composition shows little difference in the coefficient of thermal expansion from a substrate, having a small coefficient of thermal expansion, such as a silicon wafer after the composition is applied on the substrate and thermally cyclized, shows preferred adhesion property with the substrate, reduces warpage and keeps preferred developing properties, photosensitivity, or the like. As a result, a preferable pattern can be obtained. <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 excellent in 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 Non-Patent Document 1). In recent years, semiconductor devices have been highly integrated and large in size so as to respond to improved productivity of major devices such as memories and microprocessors, and to support thin packaging of information equipment devices. 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. With these circumstances, surface protection films and interlayer insulation films used for these materials have been required to have significant performance improvements in terms of heat cycle resistance, heat shock resistance, etc. Is desired.

  Further, in order to simplify the circuit pattern manufacturing process, the use of photosensitive polyimide has attracted attention.

  In the case of using photosensitive polyimide in these applications, there are known negative types in which the exposed area is cured. However, these negative types have problems with safety in the development process, and in the development process. In recent years, a positive photosensitive polyimide resin that can be developed with an aqueous alkaline solution has been developed in place of the conventional negative type because a solvent such as N-methyl-2-pyrrolidone, which is environmentally unfavorable, is used (Non-Patent Document). 2). This positive type photosensitive polyimide resin has high heat resistance, excellent electrical characteristics, and high resolution, and has attracted particular attention. Moreover, photosensitive polybenzoxazole resin excellent in moisture resistance has been developed in place of the photosensitive polyimide resin (see Non-Patent Document 2).

  However, the polyimide resin and polybenzoxazole resin have a problem that the coefficient of thermal expansion is large as compared with metals and inorganic materials.

When the thermal expansion coefficient of the resin is large, when applied to a metal or inorganic material substrate, cracks may occur in the film due to the thermal stress caused by the difference in the thermal expansion coefficient, The material may be warped or the base material may be destroyed. Further, when lithography for patterning is performed in a state where a large warp is generated in the base material, the resolution of patterning is deteriorated, 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.
“Latest Polyimide: Fundamentals and Applications” (NTS) p. 327-338 “Latest Trends in Polymer Materials for Electronic Components III (Sumibe Techno Research) p.88-119

  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 polyimide precursor composition.

  The present invention has a benzoxazole skeleton in the main chain, and an OR group in at least one of the main chain and the side chain (provided that R is a monovalent organic group that can be decomposed and converted to hydrogen by the action of an acid). A polyimide precursor containing a photoacid generator and a photoacid generator, thereby achieving the above object.

  It is preferable that the said polyimide precursor has a structure shown by General formula (1) in a repeating unit.

(Wherein R ¹ is a tetravalent organic group, R ² is an OR group, an organic group having an OR group-containing aromatic group, or other monovalent organic group, and R ³ is a general formula (2) Represents an aromatic benzoxazole residue represented by any one of (5).)

(Wherein R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represents an aromatic ring group or a heterocyclic group composed of a single ring or a plurality of rings optionally having an OR group. Represents.)

  In the positive photosensitive polyimide precursor composition having the above configuration, the total amount of OR groups contained in the entire polyimide precursor is preferably 0.5 to 3 moles per mole of repeating units.

  At least one end 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 Since the adhesiveness with the substrate is good and warpage 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 benzoxazole skeleton in the main chain, and an OR group in at least one of the main chain and the side chain (provided that R is decomposed by the action of an acid and hydrogen It is characterized by containing a polyimide precursor containing a monovalent organic group which can be converted into a photoacid generator.

  The polyimide precursor related to the present invention preferably has 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.

Here, in the above formula (1), R ¹ is a tetravalent organic group which may have an OR group, R ² is a hydroxyl group, an OR group, an organic group having an OR group-containing aromatic group, or It represents other monovalent organic groups.

  In the formula (1), regarding the OR group contained in at least one of the main chain or the side chain of the polyimide precursor, R is a monovalent organic group that can be decomposed and converted into hydrogen by the action of an acid. R is not particularly limited as long as it can be decomposed by the action of an acid and converted into a hydrogen atom, and examples thereof include an alkoxycarbonyl group, an alkoxyalkyl group, an alkylsilyl group, an acetal group, and a ketal group. These groups are known as protecting groups for protecting an alkali-soluble hydroxyl group.

  Specifically, alkoxycarbonyl groups such as t-butoxycarbonyl group, alkoxyalkyl groups such as methoxymethyl group and ethoxyethyl group, alkylsilyl groups such as methylsilyl group and ethylsilyl group, tetrahydropyranyl group, tetrahydrofuranyl group, alkoxy A substituted tetrahydropyranyl group, an alkoxy-substituted tetrahydrofuranyl group and the like are exemplified as typical examples, but are not limited thereto. The most preferred group is a tetrahydropyranyl group.

In the general formula (1), R ¹ is not particularly limited as long as it is a tetravalent organic group. However, in order to impart heat resistance to the polyimide, an aromatic ring or aromatic heterocyclic ring having 6 to 30 carbon atoms is used. It is preferable to contain. Preferred specific 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 an aromatic heterocyclic group having an OR group. Examples of such aromatic ring group or aromatic heterocyclic group 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-molar pyromellitic anhydride reaction product R ¹ corresponding Examples of such a moiety include a phenolic hydroxyl group converted to an OR group.

In the general formula (1), R ² is an OR group, an organic group having an OR group-containing aromatic group, or another monovalent organic group, and is introduced into the polyimide precursor structure by a covalent bond. Has been. The organic group having an OR group-containing aromatic 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. Considering the ease of introduction, the breadth of selection when considering the group that can be introduced, and the ease of elimination during imide ring formation, those derived from alcohol compounds or those derived from amine compounds are preferred. is there. 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 having an OR group-containing aromatic group represented by R ² include those in which the hydroxyl group of hydroxybenzyloxy group or hydroxyphenethyloxy group is an OR group. Examples of the alcohol compound having a phenolic hydroxyl group used for introducing an organic compound having a phenolic hydroxyl group that can be converted into an OR group by an ester bond include 4-hydroxybenzyl alcohol, 3-hydroxybenzyl alcohol, 2 -Hydroxybenzyl alcohol, 4-hydroxyphenethyl alcohol, etc. are mentioned. Examples of the amine compound having a phenolic hydroxyl group used for introducing an organic group containing a phenolic hydroxyl group by an amide bond include 4-hydroxybenzylamine, 3-hydroxybenzylamine, 2-hydroxybenzylamine, 4-hydroxyphenethylamine and the like can be mentioned.

Further, the other monovalent organic group represented by R ² is not particularly limited as long as it is a group that does not have an OR group. For example, it has 1 to 10 carbon atoms such as an alkyl group, an alkoxy group, and an alkylamino group. A 6-10 phenyl group, a phenoxy group, a phenylamino group, a benzyl group, etc. are mentioned.

  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 to have a rigid and straight rod-like structure.

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

In the general formulas (2) to (5), R ⁴ , R ⁵ , R ⁶ , and R ⁷ are each independently a fragrance composed of a single ring or a plurality of rings optionally having an OR group. Represents an aromatic group or a heterocyclic group.

As a specific example of R ⁴ ,

Is mentioned. Here, X in the formula is O, S, SO ₂ , S═O, CH ₂ , C═O, hexafluoroisopropylidene, isopropylidene.

Specific examples of R ⁵ include

Is mentioned. Here, X is O, S, SO ₂ , S═O, CH ₂ , C═O, hexafluoroisopropylidene or isopropylidene.

Specific examples of R ⁶ include

Is mentioned. Here, X in the formula is O, S, SO ₂ , S═O, CH ₂ , C═O, hexafluoroisopropylidene or isopropylidene.

Specific examples of R ⁷ include

Is mentioned. Here, X is O, S, SO ₂ , S═O, CH ₂ , C═O, hexafluoroisopropylidene or isopropylidene.

The bonding position for forming the main chain of R ^{4 to} R ⁷ may be arbitrary. However, in order to give the resulting polyimide a linear shape, it is bonded at the para position or within the ring structure as described above. It is preferable to combine them so that the positional relationship is as far as possible. In the chemical formulas given as examples above, preferred bonding positions are represented as # and # ', respectively.

Preferable specific examples of the group of R ^{3 represented} by any 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- And diaminobenzoxazole residues such as aminobenzoxazole).

R ⁴ , R ⁵ , R ⁶ and R ⁷ may have an OR group as a substituent. Examples of the group of R ^{3 represented} by any of R ^{4 to} R ⁷ include 5-amino-2- (m-hydroxy-p-aminophenyl) -benzoxazole and 5-amino-2- (m- Amino-p-hydroxyphenyl) -benzoxazole, 4,4′-di (m-hydroxyphenyl) ether-2,2′-bis (5-aminobenzoxazole) having a hydroxyl group substituted with R, and the like. .

  In the polyimide precursor having the above structure, the total amount of OR groups contained in the entire polyimide precursor is preferably 0.5 to 3 mol per 1 mol of the repeating unit represented by the general formula (1). If the total amount of OR groups is less than the above, 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. When the total amount of OR groups exceeds the above, film loss is large during development, and a good pattern cannot be formed.

In order to improve the adhesion between the positive photosensitive polyimide precursor composition of the present invention and the substrate, an aliphatic group having a siloxane structure is shared with R ¹ and R ³ within a range that does not decrease the heat resistance. Polymerization may be performed. Specific examples of these groups include 1 to 10 mol% copolymerized bis (3-aminopropyl) tetramethyldisiloxane as a diamine component.

  In the present invention, the polyimide is used under a condition different from the condition for forming a polyimide precursor from an aromatic diamine and a dianhydride, and a binding group that binds to the 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 kinds of functional groups with a linking group for linking the precursors.

  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 dianhydrides or primary or secondary amines containing an alkenyl group, an alkynyl group, and a cyclobutene ring. Specifically, as the diacid anhydride, maleic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, vinylphthalic anhydride, 1,2-dimethylmaleic anhydride, 4-cyclohexene-1,2 -Dicarboxylic anhydride, 1,2,3,6-tetrahydrophthalic anhydride and the like, and examples of the amine include phenylethynylaniline, ethynylaniline, 3- (3-phenylethynylphenoxy) aniline, propargylamine, And aminobenzocyclobutene. 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. Accordingly, 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 diaminobenzoxazole, but tetracarboxylic dianhydride and diaminobenzoxazole so as to have an OR group in the main chain. At least one of them containing a phenolic hydroxyl group and converting the phenolic hydroxyl group into an OR group, or R ² as an OR group so that the side chain has an OR group, or phenol A group having a hydroxyl group is introduced as R ² to convert the phenolic hydroxyl group into an OR group. When it comprises so that it may have OR group in several parts of a polyimide precursor, several OR group is introduce | transduced by combining these synthetic methods. In order to synthesize the polyimide precursor according to the present invention, a method of reacting an alcohol compound or an amine compound is known, and this method will be described as an example. First, a 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 thionyl chloride or the like. 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 or diphenyl (2,3-di-). Reaction with diaminobenzoxazole using a suitable dehydrating agent such as hydrothioxo-3-benzoxazole) phosphonate.

  When a compound having a phenolic hydroxyl group is obtained, subsequently, the resulting polyimide precursor is converted into an R skeleton by phenol nucleophilic addition reaction, or a carboxylic acid, dicarbonate, acid chloride having an R skeleton. Alternatively, a polyimide precursor containing an OR group can be obtained by reacting a chloroformate compound. Although there is no limitation in particular as an OR group introduction | transduction reaction solvent, For example, protic polar solvents, such as tetrahydrofuran and a dichloromethane, can be used.

  The positive photosensitive polyimide precursor composition of the present invention is characterized by containing a photoacid generator in addition to the polyimide precursor.

  In the positive photosensitive polyimide precursor composition according to the present invention, the photoacid generator generates an acid in the exposed portion by light irradiation, and the acid catalyst reaction by the acid generated by the photoacid generator causes the polyimide precursor to The OR group is converted to an OH group. And, by the action of the hydroxyl group or phenolic hydroxyl group of the carboxyl group contained in the polyimide precursor newly formed in the exposed area, the solubility in an alkaline aqueous solution is increased in the exposed area, thereby obtaining good positive photosensitive characteristics. It is done. Regarding such positive-type photosensitive properties, “A Basics and Applications of Photopolymer” (CMC Publishing), p. Reference is made to the description of 89-92. The positive characteristics according to the present invention are based on the difference in solubility in the alkaline aqueous solution between the exposed part and the unexposed part. The previous composition may have some alkali solubility. That is, among the OR groups contained in the polyimide precursor, those derived from phenolic hydroxyl groups can be applied as a positive type even if they remain in the hydroxyl state as long as the amount is small.

  The photoacid generator suitable for the present invention exhibits acidity upon irradiation with radiation such as ultraviolet rays, and has an action of converting an OR group in the polyimide precursor into an OH group by the produced acid. Such a photoacid generator is not particularly limited, and examples thereof include diarylsulfonium salts, triarylsulfonium salts, dialkylphenacylsulfonium salts, diaryliodonium salts, aryldiazonium salts, aromatic tetracarboxylic acid esters, aromatic sulfones. Acid esters, nitrobenzyl esters, aromatic sulfamides, naphthoquinonediazide-4-sulfonic acid esters and the like are used. Such compounds may be used in combination of two or more as required, or may be used in combination with other sensitizers.

  The photoacid generator is added in an amount of 0.01 to 50 parts by weight, preferably 3 to 15 parts by weight, based on 100 parts by weight of the polyimide precursor.

  In the positive photosensitive polyimide precursor composition of the present invention, an adhesion promoter is added to improve the adhesion between the coating film of the composition of the present invention or the polyimide film formed after heat treatment and the substrate. It may be used.

  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 further 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 positive 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., and heated to a solvent. By removing most of the above, it is possible to give a non-adhesive coating 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.

  By irradiating this coating film with a predetermined chemical beam such as ultraviolet ray, visible light, X-ray, electron beam, etc. through a mask having a predetermined pattern, by exposing to a pattern, and developing with an appropriate developer, A desired patterned film can be obtained.

  As a chemical beam irradiation apparatus, a g-line stepper, i-line stepper, contact / proximity exposure machine using an ultra-high pressure mercury lamp, mirror projection exposure machine, or other projectors that emit ultraviolet rays, visible rays, X-rays, electron beams, etc. Or a radiation source 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. By combining a photoacid generator with a polyimide precursor containing a benzoxazole skeleton in the main chain and containing an OR group in at least one of the main chain or side chain, it can be used as a positive photosensitive polyimide precursor, Moreover, it is based on having a small thermal expansion coefficient of the polyimide obtained by hardening by having a benzoxazole skeleton.

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

(Synthesis Example 1)
In a flask 1 equipped with a nitrogen introduction tube, 1 mol of 4,4′-oxydiphthalic anhydride, 2.1 mol of 4-hydroxybenzyl alcohol and 2 L of N-methyl-2-pyrrolidone (hereinafter referred to as NMP). ) And stirred, followed by dropwise addition of 2.1 mol of triethylamine over 30 minutes. After dropping, the mixture was left in this state for 3 hours, and 1 mol of 2,6- (4,4′diaminodiphenyl) -benzo [1,2-d: 5,4-d ′] bisoxazole was added after the reaction was completed. . 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 by a vacuum dryer for 12 hours.

  Next, 10 g of the obtained solid resin and 50 g of tetrahydrofuran are added to a flask equipped with a dry air introduction tube and stirred, and 26 g of 3,4-dihydro- (2H) -pyran and p-toluenesulfonic acid are catalyzed. The amount was added and allowed to react at room temperature for 5 hours. The obtained slurry-like resin was stirred in 10 L of 2-propanol solvent stirred at high speed, washed, and then dried by drying under reduced pressure to obtain a polyimide precursor 1.

(Synthesis Example 2)
To flask 1 equipped with a nitrogen inlet tube, 1 mol of pyromellitic anhydride, 2.1 mol of 4-hydroxybenzyl alcohol and 2 L of NMP were added and stirred, followed by 2.1 mol of triethylamine for 30 minutes. Dripped over. After dropping, the mixture was allowed to stand in this state for 3 hours, and 1 mol of 5-amino-2- (p-aminophenyl) -benzoxazole (p-DAMBO) 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 by a vacuum dryer for 12 hours.

  Next, 10 g of the obtained solid resin and 50 g of tetrahydrofuran are added to a flask equipped with a dry air introduction tube and stirred, and 26 g of 3,4-dihydro- (2H) -pyran and p-toluenesulfonic acid are catalyzed. The amount was added and allowed to react at room temperature for 5 hours. The obtained slurry-like resin was stirred in 10 L of 2-propanol solvent stirred at high speed, washed, and dried by drying under reduced pressure to obtain a polyimide precursor 2.

(Synthesis Example 3)
To a flask 1 equipped with a nitrogen inlet tube, 1 mol of pyromellitic anhydride, 2.1 mol of ethyl alcohol and 2 L of NMP were added and stirred, followed by dropwise addition of 2.1 mol of triethylamine over 30 minutes. . After dropping, the mixture was left in this state for 3 hours, and 1 mol of 5-amino-2- (p-amino-m-hydroxyphenyl) -benzoxazole 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 ethyl alcohol and 1 L of NMP were added to the flask 2 equipped with another nitrogen introduction tube and stirred, and then 2.1 mol of triethylamine was added for 30 minutes. Dripped over. 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 by a vacuum dryer for 12 hours.

  Next, 10 g of the obtained solid resin and 50 g of tetrahydrofuran are added to a flask equipped with a dry air introduction tube and stirred, and 26 g of 3,4-dihydro- (2H) -pyran and p-toluenesulfonic acid are catalyzed. The amount was added and allowed to react at room temperature for 5 hours. The obtained slurry-like resin was stirred in 10 L of 2-propanol solvent stirred at high speed, washed, and then dried by drying under reduced pressure to obtain a polyimide precursor 3.

(Synthesis Example 4)
To a flask 1 equipped with a nitrogen inlet tube, 1 mol of 4,4′-oxydiphthalic anhydride, 2.1 mol of ethyl alcohol and 2 L of NMP were added and stirred, followed by 30 mol of 2.1 mol of triethylamine. Added dropwise over a period of minutes. After dropping, the mixture was left in this state for 3 hours, and 1 mol of 5-amino-6-hydroxy-2- (p-amino-phenyl) -benzoxazole 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 ethyl alcohol and 1 L of NMP were added to the flask 2 equipped with another nitrogen introduction tube and stirred, and then 2.1 mol of triethylamine was added for 30 minutes. Dripped over. 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 by a vacuum dryer for 12 hours.

  Next, 10 g of the obtained solid resin and 50 g of tetrahydrofuran are added to a flask equipped with a dry air introduction tube and stirred, and 26 g of 3,4-dihydro- (2H) -pyran and p-toluenesulfonic acid are catalyzed. The amount was added and allowed to react at room temperature for 5 hours. The obtained slurry-like resin was stirred in 10 L of 2-propanol solvent stirred at high speed, washed, and then dried by drying under reduced pressure to obtain a polyimide precursor 4.

(Synthesis Example 5)
To a flask 1 equipped with a nitrogen inlet tube, 1 mol of pyromellitic anhydride, 2.1 mol of ethyl alcohol and 2 L of NMP were added and stirred, followed by dropwise addition of 2.1 mol of triethylamine over 30 minutes. . After dropping, the mixture was left in this state for 3 hours, and 1 mol of 5-amino-6-hydroxy-2- (p-amino-m-hydroxyphenyl) -benzoxazole 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 ethyl alcohol and 1 L of NMP were added to the flask 2 equipped with another nitrogen introduction tube and stirred, and then 2.1 mol of triethylamine was added for 30 minutes. Dripped over. 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 by a vacuum dryer for 12 hours.

  Next, 10 g of the obtained solid resin and 50 g of tetrahydrofuran are added to a flask equipped with a dry air introduction tube and stirred, and 26 g of 3,4-dihydro- (2H) -pyran and p-toluenesulfonic acid are catalyzed. The amount was added and allowed to react at room temperature for 5 hours. The obtained slurry-like resin was stirred in 10 L of 2-propanol solvent stirred at high speed, washed, and then dried by drying under reduced pressure to obtain a polyimide precursor 5.

(Synthesis Example 6)
To flask 1 equipped with a nitrogen inlet tube, 1 mol of pyromellitic anhydride, 2.1 mol of 4-hydroxybenzyl alcohol and 2 L of NMP were added and stirred, followed by 2.1 mol of triethylamine for 30 minutes. Dripped over. After dropping, the mixture was allowed to stand in this state for 3 hours, and 1 mol of 5-amino-2- (p-aminophenyl) -benzoxazole (p-DAMBO) 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. Further, in a flask 2 equipped with another nitrogen introduction tube, 2 mol of nadic acid anhydride (5-norbornene-2,3-dicarboxylic acid anhydride), 2.1 mol of 4-hydroxybenzyl alcohol and 1 L of NMP were added. Were added and stirred, followed by dropwise addition of 2.1 moles of triethylamine 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 by a vacuum dryer for 12 hours.

  Next, 10 g of the obtained solid resin and 50 g of tetrahydrofuran are added to a flask equipped with a dry air introduction tube and stirred, and 26 g of 3,4-dihydro- (2H) -pyran and p-toluenesulfonic acid are catalyzed. The amount was added and allowed to react at room temperature for 5 hours. The obtained slurry-like resin was stirred in 10 L of 2-propanol solvent stirred at high speed, washed, and then dried by drying under reduced pressure to obtain a polyimide precursor 6.

(Synthesis Example 7)
To flask 1 equipped with a nitrogen inlet tube, 1 mol of pyromellitic anhydride, 2.1 mol of 4-hydroxybenzyl alcohol and 2 L of NMP were added and stirred, followed by 2.1 mol of triethylamine for 30 minutes. Dripped over. After dropping, the mixture was allowed to stand in this state for 3 hours, and 1 mol of 5-amino-2- (p-aminophenyl) -benzoxazole (p-DAMBO) 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 1,2,3,4-tetrahydrophthalic 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. Subsequently, 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 by a vacuum dryer for 12 hours.

  Next, 10 g of the obtained solid resin and 50 g of tetrahydrofuran are added to a flask equipped with a dry air introduction tube and stirred, and 26 g of 3,4-dihydro- (2H) -pyran and p-toluenesulfonic acid are catalyzed. The amount was added and allowed to react at room temperature for 5 hours. The obtained slurry-like resin was stirred in 10 L of 2-propanol solvent stirred at high speed, washed, and then dried by drying under reduced pressure to obtain a polyimide precursor 7.

(Synthesis Example 8)
To a flask 1 equipped with a nitrogen inlet tube, 1 mol of pyromellitic anhydride, 2.1 mol of ethyl alcohol and 2 L of NMP were added and stirred, followed by dropwise addition of 2.1 mol of triethylamine over 30 minutes. . After dropping, the mixture was left in this state for 3 hours, and 1 mol of 2,2′-bis (3-amino-4-hydroxyphenyl) hexafluoropropane was added after the reaction was completed. 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 ethyl alcohol and 1 L of NMP were added to the flask 2 equipped with another nitrogen introduction tube and stirred, and then 2.1 mol of triethylamine was added for 30 minutes. Dripped over. 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 by a vacuum dryer for 12 hours.

  Next, 10 g of the obtained solid resin and 50 g of tetrahydrofuran are added to a flask equipped with a dry air introduction tube and stirred, and 26 g of 3,4-dihydro- (2H) -pyran and p-toluenesulfonic acid are catalyzed. The amount was added and allowed to react at room temperature for 5 hours. The obtained slurry-like resin was stirred in 10 L of 2-propanol solvent stirred at high speed, washed, and then dried by drying under reduced pressure to obtain a polyimide precursor 8.

(Synthesis Example 9)
To a flask 1 equipped with a nitrogen inlet tube, 1 mol of pyromellitic anhydride, 2.1 mol of ethyl alcohol and 2 L of NMP were added and stirred, followed by dropwise addition of 2.1 mol of triethylamine over 30 minutes. . After dropping, the mixture was left in this state for 3 hours, and 1 mol of bis (3-amino-4-hydroxyphenyl) ether was added after the reaction was completed. 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 ethyl alcohol and 1 L of NMP were added to the flask 2 equipped with another nitrogen introduction tube and stirred, and then 2.1 mol of triethylamine was added for 30 minutes. Dripped over. 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 by a vacuum dryer for 12 hours.

  Next, 10 g of the obtained solid resin and 50 g of tetrahydrofuran are added to a flask equipped with a dry air introduction tube and stirred, and 26 g of 3,4-dihydro- (2H) -pyran and p-toluenesulfonic acid are catalyzed. The amount was added and allowed to react at room temperature for 5 hours. The obtained slurry-like resin was stirred in a 10 L 2-propanol solvent stirred at high speed, washed, and dried by drying under reduced pressure to obtain a polyimide precursor 9.

(Synthesis Example 10)
To flask 1 equipped with a nitrogen inlet tube, 1 mol of pyromellitic anhydride, 2.1 mol of 4-hydroxybenzyl alcohol and 2 L of NMP were added and stirred, followed by 2.1 mol of triethylamine for 30 minutes. Dripped over. After dropping, the mixture was left in this state for 3 hours, and 1 mol of 2,2′-bis (4-aminophenyl) hexafluoropropane was added after the reaction was completed. 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 by a vacuum dryer for 12 hours.

  Next, 10 g of the obtained solid resin and 50 g of tetrahydrofuran are added to a flask equipped with a dry air introduction tube and stirred, and 26 g of 3,4-dihydro- (2H) -pyran and p-toluenesulfonic acid are catalyzed. The amount was added and allowed to react at room temperature for 5 hours. The obtained slurry-like resin was stirred in 10 L of 2-propanol solvent stirred at high speed, washed, and then dried by drying under reduced pressure to obtain a polyimide precursor 10.

(Synthesis Example 11)
To flask 1 equipped with a nitrogen inlet tube, 1 mol of pyromellitic anhydride, 2.1 mol of 4-hydroxybenzyl alcohol and 2 L of NMP were added and stirred, followed by 2.1 mol of triethylamine for 30 minutes. Dripped over. After dropping, the mixture was allowed to stand in this state for 3 hours, and 1 mol of 4,4′-diaminodiphenyl ether was added after the 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 by a vacuum dryer for 12 hours.

  Next, 10 g of the obtained solid resin and 50 g of tetrahydrofuran are added to a flask equipped with a dry air introduction tube and stirred, and 26 g of 3,4-dihydro- (2H) -pyran and p-toluenesulfonic acid are catalyzed. The amount was added and allowed to react at room temperature for 5 hours. The obtained slurry-like resin was stirred in 10 L of 2-propanol solvent stirred at high speed, washed, and then dried by drying under reduced pressure to obtain a polyimide precursor 11.

(Example 1)
100 parts by weight of the polyimide precursor obtained in Synthesis Example 1 and 10 parts by weight of diphenyliodonium-9,10-dimethoxyanthracene-2-sulfonate were dissolved in NMP to obtain a varnish of a photosensitive polyimide precursor composition. A 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 (1-50 μm remaining pattern and blank pattern) and heated at 95 ° C. for 5 minutes. Further, development was performed with a 2.38% aqueous tetramethylammonium hydroxide solution, followed by rinsing with pure water and drying. As a result, a good pattern was formed by irradiation with an exposure amount of 400 mJ / cm ² , and the residual film ratio was 94%. The appearance after development was also good. Further, heat treatment was performed at 200 ° C. for 30 minutes and at 400 ° C. for 60 minutes. The coefficient of thermal expansion is obtained from a plot of the coefficient of linear expansion obtained with respect to the temperature obtained by measuring the coefficient of linear expansion when the sample is heated in an appropriate temperature range. As a method for measuring the linear expansion coefficient, there are a TMA (thermomechanical analysis) method, a direct reading method, an optical interference method, a push rod method, a capacitance method, a SQUID method, and the like. 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. .

(Examples 2 to 7)
A photosensitive varnish was prepared in the same manner as in Example 1 except that polyimide precursors 2 to 7 were used instead of the polyimide precursor 1 used in Example 1, and evaluation was performed in the same manner as in Example 1. did.

(Comparative Examples 1-4)
A photosensitive varnish was prepared in the same manner as in Example 1 except that polyimide precursors 8 to 11 were used instead of the polyimide precursor 1 used in Example 1, and evaluation was performed in the same manner as in Example 1. did.

The evaluation results of Examples 1 to 7 and Comparative Examples 1 to 4 are shown in Table 1 below. In Table 1, “sensitivity” is the amount of exposure required to form a pattern with a resolution of 10 μm. Appearance evaluation after development is “good” if there is little development residue in the exposed area and the pattern edge is smooth. ". Calculation and calculation of the remaining film rate
Residual film ratio (%) = {(film thickness of unexposed part after development) / (film thickness of unexposed part before development)} × 100
It went by.

  According to the results shown in Table 1 above, the present invention shown in Examples 1 to 7 is clearly shown by comparing the thermal expansion coefficients of Examples 1 to 7 with those of Comparative Examples 1 to 4. Compared with the conventional polyimide (Comparative Examples 1-4), the thermal expansion coefficient of the polyimide obtained from the positive photosensitive polyimide precursor composition according to the above is clearly reduced. Moreover, when comparing the sensitivity, the remaining film rate, and the appearance after development in Examples 1 to 7 and Comparative Examples 1 to 4, Examples 1 to 7 are compared with Comparative Examples 1 to 4 in both sensitivity, remaining film rate, and developed appearance. It can be seen that the polyimide obtained from the positive photosensitive polyimide precursor according to the present invention is excellent in developability and sensitivity.

  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 (4)

  Contains a benzoxazole skeleton in the main chain and contains an OR group (where R is a monovalent organic group that can be decomposed and converted to hydrogen by the action of an acid) in at least one of the main chain and the side chain A positive photosensitive polyimide precursor composition comprising: a polyimide precursor to be prepared; and a photoacid generator. The positive-type photosensitive polyimide precursor composition according to claim 1, wherein the polyimide precursor has a structure represented by the general formula (1) in a repeating unit.

(Wherein R ¹ is a tetravalent organic group, R ² is an OR group, an organic group having an OR group-containing aromatic group, or other monovalent organic group, and R ³ is a general formula (2) Represents an aromatic benzoxazole residue represented by any one of (5).)

(Wherein R ⁴ , R ⁵ , R ⁶ and R ⁷ are each independently an OR group (where R is a monovalent organic group that can be decomposed and converted to hydrogen by the action of an acid)). Represents an aromatic ring group or a heterocyclic group composed of a single ring or a plurality of rings which may be provided.)   The positive photosensitive polyimide precursor composition of Claim 1 or 2 whose total amount of OR group contained in the said whole polyimide precursor is 0.5-3 mol per 1 mol of repeating units. At least one end 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 4. The positive photosensitive polyimide precursor composition according to any one of Items 1 to 3.