JP2005326579A - Negative photosensitive polyimide precursor composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a negative photosensitive polyimide precursor composition which has reduced lowering in adhesion to a substrate and decreases warpage of the substrate and has excellent electrical properties and resolution. <P>SOLUTION: The negative photosensitive polyimide precursor composition contains a polyimide precursor having a repeating unit shown by formula (1) wherein two symbols R<SP>2</SP>are each independently H, an organic group free from a photocrosslinkable group or an organic group containing a photocrosslinkable group and 20-100 mol% of all symbols R<SP>2</SP>of the polymer are organic groups each containing the photocrosslinkable group, and a photoinitiator. In the formula, R<SP>1</SP>and R<SP>3</SP>are as described in the specification. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a negative photosensitive polyimide precursor composition.

Conventionally, polyimide resins having excellent heat resistance, electrical characteristics, and mechanical characteristics have been used for surface protection of semiconductor elements and formation of interlayer insulating films. In addition, higher integration and larger semiconductor elements to improve the productivity of major devices such as memory and microprocessors, thinner and smaller encapsulating resin packages for thin packaging of information device devices, Accompanying surface mounting by solder reflow and the like, polyimide resin has been required to greatly improve performance in terms of heat cycle resistance and heat shock resistance. In other words, a higher performance polyimide resin is desired.
In order to simplify the process of manufacturing a circuit pattern, photosensitive polyimide has attracted attention. In place of the photosensitive polyimide resin, a photosensitive polybenzoxazole resin excellent in moisture resistance has also been developed (Patent Documents 1 and 2).

However, when a polyimide film is formed by applying a conventional photosensitive polyimide resin precursor to a substrate made of an inorganic material such as a metal, the polyimide film is cracked, the polyimide film is peeled off from the substrate, However, there is a problem that the resolution in patterning lithography is lowered. Such a problem becomes prominent when the photosensitive polyimide resin precursor is thickly applied to the substrate.
JP 2000-187324 A Japanese Patent Laid-Open No. 2001-214055

  The present invention provides a negative photosensitive polyimide precursor composition that provides a resin film that has excellent electrical characteristics and resolution, and that can reduce the decrease in adhesion to the substrate and the warpage of the substrate. It is intended to provide.

  The inventors of the present invention have noticed that the decrease in the adhesion between the resin film and the base material or the warpage of the base material occurs because the thermal expansion coefficients of the resin film and the base material are different. Furthermore, the present invention described below was completed by earnestly examining the chemical structure of a polyimide precursor for providing a polyimide resin having a thermal expansion coefficient close to that of an inorganic material used as a substrate.

The negative photosensitive polyimide precursor composition of the present invention (hereinafter also referred to as “precursor composition of the present invention”) has a repeating unit represented by the following general formula (1), and the general formula (1 two R ² are each independently a hydrogen atom in), an organic group containing an organic group or a photocrosslinking group containing no photo-crosslinkable group, 20 to 100 mol% of all R ² having a polymer A polyimide precursor in which R ² is an organic group containing a photocrosslinkable group;
A photoinitiator;
Is a negative photosensitive polyimide precursor composition.

(Where
R ¹ represents a tetravalent organic group having 2 or more carbon atoms,
R ³ represents an organic group represented by any one of the general formulas (2) to (5).

(In the general formulas (2) to (5),
X is a sulfur atom or NR ⁸ (wherein R ⁸ represents a hydrogen atom, an alkyl group or a phenyl group);
R ^{4 to} R ⁷ each independently represents an aromatic group or a heterocyclic group. ))

  When the polyimide precursor contained in the precursor composition of the present invention is imidized, a polyimide having a small thermal expansion coefficient is obtained. Therefore, after applying the negative photosensitive polyimide precursor composition of the present invention on a low thermal expansion coefficient substrate such as a silicon wafer and imidizing, a polyimide film having a small difference in thermal expansion coefficient with silicon is obtained, Such a polyimide film has good adhesion to the substrate and is less likely to warp. Moreover, it exhibits excellent developability and photosensitivity, and a good pattern can be obtained.

  The polyimide precursor composition of the present invention contains a polyimide precursor having a specific structure and a photoinitiator. The polyimide precursor has a repeating unit represented by the general formula (1) (wherein each symbol is as described above). The polyimide precursor has a structure in which a polyamic acid is a basic structure and a part or all of the side chain carboxylic acid forms a salt or is esterified.

The tetravalent organic group having two or more carbon atoms represented by R ^{1 in the} formula (1) preferably contains an aromatic ring or an aromatic heterocyclic ring, preferably 6 to 6 carbon atoms from the viewpoint of heat resistance. 30 organic groups. R ¹ can typically be expressed as a residue of tetracarboxylic dianhydride, and the tetracarboxylic dianhydride is not particularly limited, and is preferably pyromellitic acid, 1, 2, 5, 6 -Naphthalenetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 3,3 ', 4,4'-biphenyltetracarboxylic acid, 3,4 , 9,10-perylenetetracarboxylic acid, and the like.

Examples of the photocrosslinkable group in the organic group containing the photocrosslinkable group represented by R ^{2 in the} formula (1) include groups that can be eliminated, dimerized, or copolymerized by light irradiation. Can be appropriately selected from those conventionally known in the field of negative photosensitive resin compositions. The organic group containing the photocrosslinkable group represented by R ^{2 in the} formula (1) is introduced as a counter cation of (A) the carboxylic acid of the polyamic acid and bonded to the polyimide precursor via an ionic bond with the carboxylic acid. And (B) an organic group bonded to the polyimide precursor through formation of an ester with the carboxyl group of the polyamic acid.

In the case of (A), the organic group containing a photocrosslinkable group represented by R ² contains a monovalent cation formed by bonding a photocrosslinkable group-containing amine and a polyamic acid hydrogen atom. And Specific examples of the amine containing a photocrosslinkable group that gives R ² include dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, N- (2-dimethylamino). Ethyl) methacrylamide, N- (2-dimethylaminopropyl) methacrylamide, N- (2-diethylaminoethyl) methacrylamide, N- (2-dimethylaminoethyl) acrylamide, N- (2-dimethylaminopropyl) acrylamide, N- (2-diethylaminoethyl) acrylamide, acryloylmorpholine, methacryloylmorpholine, acryloylpiperazine, allylamine, triallylamine, vinylpyridine, azidobenzoic acid dimethylaminoethyl ester, azide Examples thereof include, but are not limited to, dobenzoic acid dimethylaminopropyl ester and azidosulfonylbenzoic acid dimethylaminoethyl ester.

In the case of (B), the organic group containing the photocrosslinkable group represented by R ² is preferably an organic group having an ethylenically unsaturated group, a vinyl group, an allyl group, or the like. R ² includes an acryloyloxyalkyl group having 1 to 10 carbon atoms in the alkyl group, such as a methacryloyloxymethyl group, a 2-acryloyloxyethyl group, a 3-acryloyloxypropyl group, and a 3-methacryloyloxypropyl group, and a methacryloyloxy group. An alkyl group and the like are preferable. As an application example of the present invention, a photocrosslinkable group can be introduced into a polyamic acid via an amide bond. In other words, OR ² is ^{NR 2'(wherein, R 2'is.} Of an organic group containing a photocrosslinkable group) in the general formula (1) may be replaced with. In this case, the organic group containing a photo-crosslinkable group represented by R ^2', may take the exemplary organic group as the organic group containing a photo-crosslinkable group represented by R ^2.

In the case of (A), both the case of (B), 20 to 100 mol% of all ^{R 2} with the polymer, preferably an organic group of ^{R 2} is from 50 to 100 mol% containing photocrosslinkable groups is there. When R ² of less than 20 mole% of all R ² having the polymer is an organic group containing a photocrosslinkable group, requires a large amount of light energy to light sensitivity is insufficient, Further, since the crosslinking is insufficient, there is a disadvantage that the resolving power is low and the remaining film ratio is small.

The organic group that does not contain the photocrosslinkable group represented by R ^{2 in} Formula (1) is an organic group that does not have the above-described photocrosslinkable group. In the case of the above (A), the organic group is preferably a hydrocarbon group having 1 to 30 carbon atoms or an alkoxyalkyl group, but is not limited thereto. Preferred specific examples include, but are not limited to, methyl group, ethyl group, isopropyl group, butyl group, methoxyethyl group, phenyl group, benzyl group and the like. In the case of the above (B), the organic group not containing the photocrosslinkable group represented by R ^{2 in} the formula (1) is an alkyl group having 1 to 10 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, or a benzyl group. Etc.

In the case of (A), 50 to 100 mol% of R ² out of all R ² possessed by the polymer is preferably hydrogen, and more preferably 80 to 100 mol%. “Hydrogen” in calculating the ratio includes a hydrogen atom that forms a monovalent cation by bonding with an amine containing a photocrosslinkable group. As the proportion of hydrogen increases, the remaining proportion of leaving groups in the cured film decreases, and there is an advantage that conversion to polyimide occurs quickly.

When R ² is a hydrogen atom, the side chain of the precursor of the present invention represented by the general formula (1) may be left as carboxylic acid, or an alkali metal salt or ammonium salt is formed. Also good. Examples of the alkali metal salt in the above case include lithium salt, sodium salt, potassium salt and the like.

Formulas (2) to (5) referred to by R ^{3 in} Formula (1) will be described.
The aromatic group or heterocyclic group represented by R ^{4 in the} formulas (2) to (3) is a tetravalent group corresponding to an aromatic compound or heterocyclic compound obtained by removing four hydrogens. Specific examples of the aromatic group or heterocyclic group represented by R ^{4 in the} formulas (2) to (3) include

(Wherein X ⁴ is an oxygen atom, a sulfur atom, SO ₂ , S═O, CH ₂ , C═O, hexafluoroisopropylidene or isopropylidene).

The aromatic group or heterocyclic group represented by R ^{5 in the} formulas (2) to (4) is a divalent group corresponding to an aromatic compound or heterocyclic compound obtained by removing two hydrogens. 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 or isopropylidene).

The aromatic group or heterocyclic group represented by R ^{6 in} formulas (4) to (5) is a trivalent group corresponding to an aromatic compound or heterocyclic compound obtained by removing three hydrogen atoms. 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 or isopropylidene).

The aromatic group or heterocyclic group represented by R ^{7 in} formula (5) is a divalent group corresponding to an aromatic compound or heterocyclic compound obtained by removing two hydrogen atoms. 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).

The alkyl group represented by R ^{8 in} NR ⁸ referred to by X in formulas (2) to (5) is preferably an alkyl group having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms.

The organic group represented by R ^{3 in the} formula (1) is preferably a benzothiazole residue or a benzimidazole residue. Specific examples of preferred benzothiazole residues include 2,6- (4,4′-diaminodiphenyl) benzo [1,2-d: 5,4-d ′] bisthiazole, 5-amino-2- (p- Divalent benzothiazole divalent residues such as aminophenyl) -benzothiazole, 5-amino-2- (m-aminophenyl) -benzothiazole, 2,2'-p-phenylenebis (5-aminobenzothiazole) Specific examples of preferred benzimidazole residues include 2,6- (4,4′-diaminodiphenyl) benzo [1,2-d: 5,4-d ′] bisimidazole, 5-amino-2 -(P-aminophenyl) -benzimidazole, 5-amino-2- (m-aminophenyl) -benzimidazole, 2,2'-p-phenylenebis (5-aminobenzimid) Tetrazole) include divalent residues of diamino benzimidazole such.

  At least one terminal of the main chain of the polyimide precursor used in the present invention may be sealed with a chain extender having a binding group via the binding group. The binding group possessed by the chain extender is a functional group that binds to an aromatic diamine or dianhydride. The chain extender further has a linking group. The linking group is an organic group capable of linking the polyimide precursors via the chain extender under conditions different from the conditions for synthesizing the polyimide precursor from aromatic diamine and dianhydride. is there. Specific examples of the chain extender include an alkenyl group, an alkynyl group, a dianhydride containing a cyclobutene ring, or a primary or secondary amine. More specifically, for example, 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, phenylethynyl Examples include aniline, ethynylaniline, 3- (3-phenylethynylphenoxy) aniline, propargylamine, aminobenzocyclobutene, and the like. The amount of chain extender is generally selected to obtain the desired molecular weight and viscosity of the solution, and increasing the amount reduces the molecular weight of the polyimide precursor and hence the viscosity of the solution containing it. Since the optimum solution viscosity exists depending on the coating method, it is preferable to determine the amount of the chain extender in consideration of the concentration of the solution and the coating method.

In the polyimide precursor used in the present invention, in order to improve the adhesion between the polyimide film and the substrate, an aliphatic group having a siloxane structure is introduced into R ¹ and R ³ within a range that does not lower the heat resistance. May be. In other words, bis (3-aminopropyl) tetramethyldisiloxane or the like in an amount of 1 to 10 mol% of the total diamine component for obtaining the polyamic acid may be copolymerized.

The polyimide precursor of the present invention is synthesized by a known method. When R ² is a hydrogen atom, a tetracarboxylic dianhydride is selectively combined with diaminobenzothiazole or diaminobenzimidazole, and these are combined with N-methyl-2-pyrrolidone, N, N-dimethylacetamide, It is synthesized by a known method such as reacting in a polar solvent mainly containing N, N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphorotriamide or the like or a solvent mainly containing γ-butyrolactone.

When R ² is an alkyl group, after reacting a tetracarboxylic dianhydride and an alcohol compound, synthesizing an acid chloride using thionyl chloride or the like, diaminobenzothiazole or diaminobenzimidazole is selectively used. Or using a suitable dehydrating agent such as cyclohexylcarbodiimide or diphenyl (2,3-dihydro-thioxo-3-benzoxazole) phosphonate, and selectively combining diaminobenzothiazole or diaminobenzimidazole with N-methyl Such as reacting in a polar solvent mainly composed of 2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphorotriamide or the like, or in a solvent mainly composed of γ-butyrolactone. In a known manner It is made.

  Photoinitiators contained in the precursor composition of the present invention include aromatic amines such as N-phenyldiethanolamine, N-phenylglycine, and Michler's ketone, cyclic oxime compounds such as 3-phenyl-5-isoxazolone, 1-phenyl Chain oxime compounds such as propanedione-2- (o-ethoxycarbonyl) oxime, benzophenone, benzophenone derivatives such as methyl o-benzoylbenzoate, dibenzylketone, fluorene, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, etc. The thioxanthone derivative is not limited to these.

  The photoinitiator is added in an amount of 0.01 to 30 parts by weight, preferably 0.1 to 20 parts by weight, based on 100 parts by weight of the polyimide precursor. If it is out of this range, there arises a problem that the sensitivity is lowered or the mechanical strength is lowered.

  The precursor composition of the present invention may further contain a sensitizer. Examples of such a sensitizer include aromatic monoazides such as azidoanthraquinone and azidobenzalacetophenone, and 3,3′-carbonylbis. Examples include compounds used in general photosensitive resins such as coumarin compounds such as (diethylaminocoumarin) and aromatic ketones such as benzoanthrone and phenanthrenequinone.

  Content in case the precursor composition of this invention contains a sensitizer is 0.01-30 weight part with respect to 100 weight part of polyimide precursors, Preferably it is 0.1-20 weight part. If it is in this range, the sensitivity will be good and the decrease in mechanical strength can be suppressed.

  The precursor composition of the present invention can use an adhesion promoter in order to improve the adhesion between the coating film or the resin film after the heat treatment and the substrate. 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 preferably mentioned. The precursor composition of the present invention may further contain other additives such as a plasticizer, a dye, and a polymerization inhibitor as long as the adhesion to the substrate, sensitivity, resolution, heat resistance and the like are not impaired.

  The precursor composition of the present invention can be obtained in solution by dissolving in a solvent. Examples of the solvent include N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphortriamide, γ-butyrolactone, ethylene carbonate, Propylene carbonate, sulfolane, dimethylimidazoline, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and the like can be used. These may be used alone or in combination.

  The 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, or the like, and heated to remove most of the solvent. By this, the coating film without adhesiveness can be given to the substrate surface. Although there is no restriction | limiting in particular in the thickness of a coating film, 4-50 micrometers is preferable. This coating film is irradiated with actinic radiation through a mask having a predetermined pattern, exposed in a pattern, and then the unexposed portion of the film is developed and removed with an appropriate developer to obtain a desired pattern. Can be obtained. Ultraviolet, visible light, X-rays, electron beams, etc. can be used as actinic radiation, and contact / proximity exposure machines and mirror projection exposure machines that use g-line steppers, i-line steppers, and ultra-high pressure mercury lamps as chemical radiation irradiation devices. Etc. As the developer, for example, a good solvent (for example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, etc.), the good solvent and a poor solvent (for example, lower alcohols, ketones) , Water, aromatic hydrocarbons, etc.) or an alkaline developer.

  After development, if necessary, it is desirable to wash the coating film with water or a poor solvent and then dry the coating film at about 100 ° C. to stabilize the pattern. By heating the coating film on which the pattern is formed, a polyimide 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.

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

(Synthesis Example 1)
Into a 300 ml three-necked separable flask equipped with a stirrer and a condenser, 100 ml of N-methyl-2-pyrrolidone (NMP) and 22.32 g (60 mmol) of 2,6- (4,4′-diaminodiphenyl) -benzo [1,2-d: 5,4-d '] bisthiazole is added to form a suspension, and the flask is gently purged with nitrogen for 30 minutes. The reaction system was ice-cooled (below 5 ° C.), and 12.04 g (55.205 mmol) of pyromellitic dianhydride (PMDA) and 0.95 g (9.6 mmol) of maleic anhydride were added to the reaction system. The mixture was stirred at room temperature for about 68 hours to obtain a polyimide precursor composition 1.

(Synthesis Example 2)
In the same manner as in Synthesis Example 1, 100 ml of NMP, 14.46 g (60 mmol) of 5-amino-2- (p-aminophenyl) -benzothiazole, 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 polyimide precursor 2.

(Synthesis Example 3)
In the same manner as in Synthesis Example 1, 100 ml of NMP, 14.46 g (60 mmol) of 5-amino-2- (p-aminophenyl) -benzothiazole, 0.95 g (9.6 mmol) of maleic anhydride and 16 .25 g (55.205 mmol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was reacted at room temperature for 45 hours to obtain polyimide precursor 3.

(Synthesis Example 4)
1. 1 mol of pyromellitic anhydride, 2.1 mol of hydroxyethyl methacrylate and 2 L of N-methyl-2-pyrrolidone (NMP) were added to the flask 1 equipped with a nitrogen inlet tube and stirred. 1 mol of triethylamine was added dropwise for 30 minutes. After standing in this state for 3 hours, 1 mol of 2,6- (4,4′-diaminodiphenyl) -benzo [1,2-d: 5,4-d ′] bisthiazole was added. Next, 2.1 mol of diphenyl (2,3-dihydro-thioxo-3-benzoxazole) phosphonate was added in 5 portions and condensed in that state for 5 hours. In addition, 2 mol of maleic anhydride, 2.1 mol of hydroxyethyl methacrylate and 1 L of N-methyl-2-pyrrolidone (NMP) were added to the flask 2 equipped with another nitrogen introduction tube, and the stirring was continued. 2.1 mol of triethylamine was added dropwise for 30 minutes. After leaving in this state for 3 hours, the solution of flask 2 was added to flask 1 and mixed, and stirred for 30 minutes. Next, 2.1 mol of diphenyl (2,3-dihydro-thioxo-3-benzoxazole) phosphonate was added in 5 portions and condensed in that state for 5 hours. The obtained slurry-like mixture was put into a large amount of methanol and washed, and the obtained solid resin was dried by a vacuum dryer for 12 hours to synthesize a polyimide precursor 4.

(Synthesis Example 5)
Instead of 2,6- (4,4′-diaminodiphenyl) -benzo [1,2-d: 5,4-d ′] bisthiazole, 5-amino-2- (p-aminophenyl) -benzothiazole is used. A polyimide precursor 5 was synthesized by the same operation as in Synthesis Example 4 except that it was used.

(Synthesis Example 6)
3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was used in place of pyromellitic anhydride, and 2,6- (4,4′-diaminodiphenyl) -benzo [1,2 -D: 5,4-d '] Polyimide precursor 6 was prepared in the same manner as in Synthesis Example 4 except that 5-amino-2- (p-aminophenyl) -benzothiazole was used instead of bisthiazole. Synthesized.

(Synthesis Example 7)
In the same manner as in Synthesis Example 1, 100 ml of NMP, 20.64 g (60 mmol) of 2,6- (4,4′-diaminodiphenyl) -benzo [1,2-d: 5,4-d ′] bis Polyimide precursor 7 was synthesized by reacting imidazole, 0.95 g (9.6 mmol) maleic anhydride and 12.04 g (55.205 mmol) pyromellitic dianhydride (PMDA) at room temperature for 45 hours. did.

(Synthesis Example 8)
In a manner similar to Synthesis Example 1, 100 ml NMP, 13.56 g (60 mmol) 5-amino-2- (p-aminophenyl) -benzimidazole, 0.95 g (9.6 mmol) maleic anhydride and 12 Polyimide precursor 8 was synthesized by reacting .04 g (55.205 mmol) of pyromellitic dianhydride (PMDA) at room temperature for 45 hours.

(Synthesis Example 9)
In the same manner as in Synthesis Example 1, 100 ml of NMP, 13.56 g (60 mmol) of 5-amino-2- (p-aminophenyl) -benzimidazole, 0.95 g (9.6 mmol) of maleic anhydride and 16 A polyimide precursor 9 was synthesized by reacting .25 g (55.205 mmol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride at room temperature for 45 hours.

(Synthesis Example 10)
Instead of 2,6- (4,4′-diaminodiphenyl) -benzo [1,2-d: 5,4-d ′] bisthiazole, 2,6- (4,4′-diaminodiphenyl) -benzo [ A polyimide precursor 10 was synthesized in the same manner as in Synthesis Example 4 except that 1,2-d: 5,4-d ′] bisimidazole was used.

(Synthesis Example 11)
Instead of 2,6- (4,4′-diaminodiphenyl) -benzo [1,2-d: 5,4-d ′] bisthiazole, 5-amino-2- (p-aminophenyl) -benzimidazole is used. A polyimide precursor 11 was synthesized by the same operation as in Synthesis Example 4 except that it was used.

(Synthesis Example 12)
3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was used in place of pyromellitic anhydride, and 2,6- (4,4′-diaminodiphenyl) -benzo [1,2 -D: 5,4-d '] Polyimide precursor 12 was prepared in the same manner as in Synthesis Example 4 except that 5-amino-2- (p-aminophenyl) -benzimidazole was used instead of bisthiazole. Synthesized.

(Synthesis Example 13)
In the same manner as in Synthesis Example 1, 100 ml of NMP, 12.01 g (60 mmol) of 4,4′-diaminodiphenyl ether, 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 synthesize polyimide precursor 13.

(Synthesis Example 14)
In the same manner as in Synthesis Example 1, 100 ml of NMP, 19.90 g (60 mmol) of 4,4′-diaminodiphenylsulfone, 1.58 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 synthesize polyimide precursor 14.

(Example 1)
100 parts by weight of polyimide precursor 1 with 5 parts by weight of N-phenyldiethanolamine, 1 part by weight of 1-phenylpropanedione-2- (o-ethoxycarbonyl) oxime, 0.5-diethylamino-3-benzoylcoumarin 0.5 A part by weight was added, and diethylaminoethyl methacrylate was added at a ratio of 2 mol to 1 mol of the structural unit of the polyimide precursor 1. Furthermore, it diluted with NMP so that the viscosity of a varnish might be set to about 50 poise, and the photosensitive varnish was obtained. This photosensitive 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 blank pattern). Thereafter, development was performed after pre-baking at 80 ° C. for 2 minutes on a hot plate. Development was performed using a mixed solvent of N-methylpyrrolidone (70 parts) and methanol (30 parts). Next, the silicon wafer was rinsed with isopropanol 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 90%. Further, the appearance after development was good. Furthermore, heat treatment was performed at 200 ° C. for 30 minutes and then at 400 ° C. for 60 minutes. The film after the heat treatment was peeled off from the silicon wafer, and measured by a TMA (thermomechanical analysis) method at a temperature rising rate of 10 ° C./min in the range of 25 to 200 ° C., it was 5 ppm / ° C.

(Examples 2-3 and 7-9)
A photosensitive varnish was prepared in the same manner as in Example 1 except that the polyimide precursors 2 to 3 and 7 to 9 were used instead of the polyimide precursor 1 and evaluated in the same manner as in Example 1. .

Example 4
100 parts by weight of polyimide precursor weight 4; 2 parts by weight of N-phenyldiethanolamine; 4 parts by weight of 1-phenylpropanedione-2- (o-ethoxycarbonyl) oxime; 7-diethylamino-3-benzoylcoumarin; 5 parts by weight, 10 parts by weight of tetraethylene glycol dimethacrylate, 2 parts by weight of γ-glycidoxypropylmethyldimethoxysilane, and 0.1 parts by weight of N-nitrosodiphenylamine were added. Furthermore, it diluted with NMP so that a varnish viscosity might be set to about 50 poise, and the photosensitive varnish was obtained. This photosensitive 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). Thereafter, development was performed after pre-baking at 80 ° C. for 2 minutes on a hot plate. Development was performed using a mixed solvent of N-methylpyrrolidone (70 parts) and methanol (30 parts). Next, the silicon wafer was rinsed with isopropanol 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 90%. The appearance after development was also good. Further, heat treatment was performed at 200 ° C. for 30 minutes and then at 400 ° C. for 60 minutes in a nitrogen atmosphere. The film after the heat treatment was peeled off from the silicon wafer and measured by a TMA (thermomechanical analysis) method in the range of 25 to 200 ° C. at a rate of temperature increase of 10 ° C./min. The coefficient of thermal expansion was 5 ppm / ° C.

(Examples 5-6, 10-12)
A photosensitive varnish was prepared in the same manner as in Example 4 except that polyimide precursors 5 to 6 and 10 to 12 were used instead of the polyimide precursor 4 and evaluated in the same manner as in Example 4. .

(Comparative Examples 1-2)
A photosensitive varnish was prepared in the same manner as in Example 1 except that the polyimide precursors 13 to 14 were used instead of the polyimide precursor 1 and evaluated in the same manner as in Example 1.

The evaluation results for each example and comparative example are summarized in Table 1. In Table 1, “sensitivity” is the amount of exposure required to form a pattern with a resolution of 10 μm, and the appearance evaluation after development is “good” if there is no unexposed development residue and the pattern edge is smooth. It was evaluated. The remaining film rate is calculated by the following formula.
Residual film ratio (%) = (film thickness after development) / (film thickness after pre-baking treatment) × 100

  As is clear from Table 1, the polyimide obtained from the negative photosensitive polyimide precursor composition of the present invention has a small coefficient of thermal expansion, and is excellent in developability and sensitivity.

Claims (1)

It has a repeating unit represented by the following general formula (1), and two R ² in the general formula (1) each independently contain a hydrogen atom, an organic group that does not contain a photocrosslinkable group, or a photocrosslinkable group. an organic group, the polyimide precursor is an organic group of 20 to 100 mol% of R ² of all R ² having the polymer contains photocrosslinkable groups,
A photoinitiator;
A negative photosensitive polyimide precursor composition containing:

(Where
R ¹ represents a tetravalent organic group having 2 or more carbon atoms,
R ³ represents an organic group represented by any one of the general formulas (2) to (5).

(In the general formulas (2) to (5),
X is a sulfur atom or NR ⁸ (wherein R ⁸ represents a hydrogen atom, an alkyl group or a phenyl group);
R ^{4 to} R ⁷ each independently represents an aromatic group or a heterocyclic group. ))