Photosensitive polyimide resin composition

Abstract

To provide a photosensitive polyimide resin composition that has developer solubility during development and developer insolubility after photo-crosslinking, achieves excellent film properties and high sensitivity, and protects a resin coat from peeling or cracking and also protects a substrate from warpage and breakage.SOLUTION: A photosensitive polyimide resin composition contains a solvent-soluble polyimide and a diazide compound. The solvent-soluble polyimide is a block copolymer that has, in a same repeat unit, (a) an alicyclic acid dianhydride residue and (b) a residue of a diamine selected from a group consisting of an aromatic diamine having an alkyl group at an ortho position of an amino group and an aromatic diamine having an indan structure.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photosensitive polyimide resin composition. [Background technology]

[0002] In recent years, in the field of semiconductor package substrates, there has been active consideration of a shift from FC-CSP and FC-BGA to Fan-out Wafer Level Package (FO-WLP), which allows for a lower height, improved electrical properties (R, L, C), and reduced warpage, and some FO-WLPs have been mass-produced. In addition, Fan-out Panel Level Package (FO-PLP), which uses panel-sized materials, is also being actively considered. The key organic materials used in these FO-WLPs and FO-PLPs are the encapsulation material and various protective film materials, and photosensitive polyimide is used as the protective film material.

[0003] Methods for imparting photosensitivity to photosensitive polyimides are broadly divided into positive-type and negative-type. In the negative-type photosensitivity imparting method, the exposed portion undergoes a photocrosslinking reaction and remains after development processing, making it easier to improve chemical resistance and heat resistance, and providing a material with excellent reliability. Negative-type photosensitive polyimides are broadly divided into a method in which a photosensitive group is introduced into a precursor such as polyamic acid, and thermal imidization is performed after the photoreaction, and a method in which the ring-closed polyimide itself is made photosensitive.

[0004] Representative methods that have been put to practical use in this field include a method using a precursor such as polyamic acid, in which a polyamic acid is ester-bonded with a hydroxyacrylate (Patent Document 1), or a method in which an aminoacrylate or the like is blended with a polyamic acid to introduce a photosensitive group through a salt bond (Patent Document 2).

[0005] Furthermore, as a negative-type photosensitive composition aimed at reducing the thermal expansion coefficient, a composition containing a polyimide precursor having a benzoxazole skeleton in the main chain has been reported (Patent Documents 3 and 4).

[0006] Furthermore, as a photosensitive composition aimed at reducing residual stress, a resin composition consisting of a polyimide precursor having a photosensitive group, a photoinitiator, and a solvent has been reported, and the polyimide precursor used is one synthesized from various aromatic tetracarboxylic dianhydrides and diamines (Patent Document 5).

[0007] Furthermore, a metal wiring board for a power module having a metal substrate, a polyimide resin layer, and a conductive metal wiring layer has been reported, which ensures both insulation and thermal conductivity and improves the heat dissipation and reliability of the power module (Patent Document 6). Here, it is described that, from the viewpoint of achieving heat resistance and a low linear thermal expansion coefficient, thermoplastic and non-thermoplastic polyimide resins synthesized using aromatic tetracarboxylic dianhydrides can be preferably used as the polyimide resin.

[0008] On the other hand, as a method for imparting photosensitivity to a ring-closed polyimide itself, there have been reported a method using a polyimide copolymer obtained by a polycondensation reaction between a tetracarboxylic dianhydride having a benzophenone structure and a diamine (Patent Document 7), and a method in which an acryloyl group is added to the side chain of a solvent-soluble polyimide block copolymer synthesized by two-stage polycondensation (Patent Document 8).

[0009] In addition, it has been disclosed that a negative-type photosensitive polyimide composition containing a solvent-soluble polyimide having an aromatic or alicyclic tetracarboxylic dianhydride residue and an aromatic diamine residue, and a photoradical generator has high image resolution and is excellent in adhesion, heat resistance, mechanical properties, and flexibility (Patent Document 9).

[0010] Furthermore, it has been reported that a photosensitive polyimide resin composition containing a solvent-soluble polyimide having in its main chain an aromatic tetracarboxylic dianhydride residue having a benzophenone structure, and an aromatic diamine residue having an alkyl group at the ortho position of the amino group or an aromatic diamine residue having an indane structure, and a specific amount of a diazide compound, has both solvent solubility during development and solvent insolubility after photocrosslinking, and can achieve good film properties and high sensitivity (Patent Document 10). [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Special Publication No. 55-41422 [Patent Document 2] Japanese Patent Application Publication No. 54-145794 [Patent Document 3] JP 2005-321648 A [Patent Document 4] JP 2005-321650 A [Patent Document 5] JP 2001-110898 A [Patent Document 6] JP 2015-97258 A [Patent Document 7] Japanese Patent Application Publication No. 5-39281 [Patent Document 8] JP 2000-147768 A [Patent Document 9] International Publication No. 2002 / 023276 [Patent Document 10] International Publication No. 2020 / 246565 Summary of the Invention [Problem to be solved by the invention]

[0012] The requirements for semiconductor package substrates are becoming more stringent every year, and FO-WLP and FO-PLP are no exception, with demands for thinner patterns, smaller diameter connection vias, and multi-layering. In order to meet these demands, photosensitive polyimides are also being required to improve sensitivity and thin film reliability, as well as reduce warping and improve dimensional stability in large panel sizes, which are deeply related to cost reduction, the biggest challenge for FO-WLP and FO-PLP. One of the elements of this is a low coefficient of thermal expansion.

[0013] Conventional photosensitive polyimide resins have a large coefficient of thermal expansion compared to metals and inorganic materials. When a resin has a large coefficient of thermal expansion, when it is applied to a metal or inorganic substrate to form a resin coating, the thermal stress caused by the difference in coefficient of thermal expansion may cause cracks in the formed resin coating, peel off the resin coating from the substrate, warp the substrate, or destroy the substrate. Furthermore, when lithography is performed for patterning in a state where the substrate is significantly warped, the resolution of the patterning may deteriorate. This problem is particularly noticeable when a substrate with a large panel size is used or when a thick resin is applied to the substrate. Therefore, the development of a photosensitive polyimide resin with a small coefficient of thermal expansion is desired. In particular, when a silicon wafer is used as the substrate, its coefficient of thermal expansion is very small at 3 ppm / ℃, and the difference in thermal expansion with the polyimide resin may cause the wafer to warp, which is undesirable in terms of defects, transport defects, and cracking in the manufacturing process, or the effect on device characteristics (electrical characteristics, resolution).

[0014] In order to meet these demands, polyamic acid type photosensitive polyimide resin compositions such as those in the above Patent Documents 3 to 6 have been investigated, but sufficient performance has not yet been achieved. In addition, the method using the polyamic acid type photosensitive composition requires a step of performing high temperature treatment (for example, 350 to 450°C) for imidization after coating and drying on a substrate, or after exposure and development, during which dehydration shrinkage and elimination or volatilization of photosensitive groups occur, resulting in large film defects. This has a significant impact on the warping and dimensional stability of the substrate in the manufacturing process of semiconductor packages and electronic elements, and has also been a factor in reducing storage stability.

[0015] Moreover, even the photosensitive compositions using ring-closed polyimides described in the above Patent Documents 7 to 10 are still insufficient in terms of reducing the thermal expansion coefficient.

[0016] Thus, as a protective film material for semiconductor package substrates and the like, there has been a demand for a photosensitive polyimide resin composition which does not suffer from high-temperature treatment for imidization, or from defects or cracks in the resin coating film or warpage or damage to the substrate which are caused by the difference in thermal expansion coefficient between the polyimide resin and the substrate.

[0017] An object of the present invention is to provide a photosensitive polyimide resin composition which is soluble in a developer during development and insoluble in a developer after photocrosslinking, and which can achieve good film properties and high sensitivity, while preventing the occurrence of defects or cracks in the resin coating and the warping or destruction of the substrate. [Means for solving the problem]

[0018] The present inventors have conducted extensive research to solve the above problems, and have found that a resin composition containing a ring-closed solvent-soluble polyimide, which has (a) an alicyclic acid dianhydride residue and (b) an aromatic diamine residue having an alkyl group at the ortho position of an amino group or an aromatic diamine having an indane structure in the same repeating unit, and a resin composition containing this solvent-soluble polyimide and a diazide compound, can be obtained with a significantly reduced thermal expansion coefficient.The present inventors have found that the above problems can be solved by using such a resin composition, and that a photosensitive polyimide resin composition can be provided that is soluble in a developer during development and insoluble in a developer after photocrosslinking, can achieve good film properties and high sensitivity, and does not cause film defects or cracks in the resin coating, or warp or breakage of the substrate, and have completed the present invention.

[0019] That is, the present invention provides a photosensitive polyimide resin composition containing a solvent-soluble polyimide and a diazide compound as essential components, wherein the solvent-soluble polyimide is a block copolymer having, in the same repeating unit, (a) an alicyclic acid dianhydride residue and (b) a residue of at least one diamine selected from the group consisting of an aromatic diamine having an alkyl group at the ortho-position of an amino group and an aromatic diamine having an indane structure. The present invention also provides a method for forming a pattern, which comprises exposing a substrate coated with the resin composition of the present invention to ultraviolet light and developing and removing the unexposed areas. The present invention further provides a semiconductor package, a magnetic element, a display element, or an organic multilayer wiring board having an interlayer insulating film, a passivation film, or a surface protective film formed using the resin composition of the present invention. Effect of the Invention

[0020] According to the present invention, a photosensitive polyimide resin composition can be provided which is soluble in a developer during development and insoluble in a developer after photocrosslinking, and which can achieve good film properties and high sensitivity, without using a polyamic acid which requires imidization at high temperatures, and which is free from film defects or cracks in the resin coating, or warpage or damage to the substrate, and has a low thermal expansion coefficient. Furthermore, when the thickness of the film formed using the polyimide resin composition is large, for example, 10 μm or more, a sufficient crosslinked structure can be realized by further incorporating a photobase generator and an epoxy resin in the photosensitive polyimide resin composition of the present invention and photocrosslinking the epoxy resin with the photobase generator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The photosensitive polyimide resin composition of the present invention is a resin composition containing (A) a solvent-soluble polyimide and (B) a diazide compound as essential components.

[0022] (A) Solvent-soluble polyimide The (A) solvent-soluble polyimide of the present invention is a block copolymer having (a) an alicyclic acid dianhydride residue and (b) a diamine residue having a specific structure in the same repeating unit. (b) The diamine residue having a specific structure is a residue of at least one diamine selected from the group consisting of (b-1) an aromatic diamine having an alkyl group at the ortho position of the amino group and (b-2) an aromatic diamine having an indane structure.

[0023] Specifically, the solvent-soluble polyimide (A) of the present invention is a block copolymer having at least one of the repeating units represented by the following general formulas [I] and [II].

[0024] [ka]

[0025] (In the formula, Z 1 is an alicyclic dianhydride residue, and Ar 1 is an aromatic diamine residue having an alkyl group at the ortho position of the amino group.

[0026] [ka]

[0027] (In the formula, Z 2 is an alicyclic dianhydride residue, and Ar 2 is an aromatic diamine residue having an indane structure.

[0028] (a) Alicyclic acid dianhydride residue (a) Examples of alicyclic acid dianhydrides providing alicyclic acid dianhydride residues include 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, cyclohexane-1,2,3,4-tetracarboxylic acid dianhydride, cyclohexane-1,2,4,5-tetracarboxylic acid dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic acid dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethynylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 2,2-propanediol-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, and the like. propylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1,1,3,3,3-hexafluoro-2,2-propylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, 1-carboxymethyl-2,3,5-cyclopentane tricarboxylic acid-2,6:3,5-dianhydride, and 3-carboxymethyl-1,2,4-cyclopentane tricarboxylic acid-1,4:2,3-dianhydride. These may be used alone or in combination of two or more. Among them, in order to achieve a low thermal expansion coefficient, tetracarboxylic dianhydrides of cycloalkanes having 4 to 7 carbon atoms are preferred, and 1,2,3,4-cyclobutane tetracarboxylic dianhydride or 1,2,3,4-cyclopentane tetracarboxylic dianhydride is more preferred.

[0029] Polyimides based on 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), an alicyclic acid dianhydride, have almost no absorption in the visible light region from 300 nm to 800 nm, and transmit almost all exposure wavelengths such as g-line (436 nm) and i-line (365 nm). By using a photosensitive polyimide such as this CBDA polyimide as a base polymer, it is possible to effectively utilize the exposure wavelength, and a photosensitive polyimide with high sensitivity and high resolution can be obtained.

[0030] In the present invention, in order to increase the transmittance in the visible light region and achieve high sensitivity and high resolution while simultaneously achieving a low coefficient of thermal expansion and solvent solubility, it is necessary to add (a) an alicyclic acid dianhydride residue (Z 1 and Z 2 ) is preferably contained in an amount of 5 mol % or more, 10 mol % or more, 15 mol % or more, or even 20 mol % or more, and 65 mol % or less, 60 mol % or less, or even 55 mol % or less of all the acid dianhydride residues constituting the (A) solvent-soluble polyimide.

[0031] In order to achieve both a low thermal expansion coefficient and solvent solubility, other aromatic acid dianhydrides can be used in combination. Examples of other aromatic acid dianhydrides include 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 4,4'-[propane-2,2-diylbis(1,4-phenyleneoxy)]diphthalic acid dianhydride, 4,4'-oxydiphthalic acid anhydride, and pyromellitic acid dianhydride.

[0032] Furthermore, in order to maintain the solvent solubility of the polyimide while further increasing the transmittance in the visible light region, a fluorine-based acid dianhydride can be used in combination. The fluorine-based acid dianhydride includes aromatic acid dianhydrides having a fluorine atom (or a substituent containing a fluorine atom), and representative examples thereof include 4,4'-(hexafluoroisopropylidene)diphthalic anhydride and 2,2'-bis(trifluoromethyl)-3,3',4,4'-biphenyltetracarboxylic dianhydride.

[0033] (b) a diamine residue having a specific structure (b-1) Residue of an aromatic diamine having an alkyl group at the ortho position of the amino group An aromatic diamine residue having an alkyl group at the ortho position of the amino group (Ar 1 ) includes residues of aromatic diamines having a linear or branched alkyl group having 1 to 12 carbon atoms, preferably 1 to 5 carbon atoms, and more preferably 1 to 3 carbon atoms, at the ortho position of the amino group. Specific examples include residues of aromatic diamines having structures represented by the following formulas (1) to (3) and heterocyclic diamines having a dibenzothiophene sulfone structure or the like.

[0034] [ka]

[0035] In the above formula (1), the free bonds (the two bond positions to which amino groups are bonded) are present in the meta or para positions relative to each other, but from the viewpoint of obtaining a polyimide having a main chain skeleton with high linearity in order to reduce the thermal expansion coefficient, it is preferable that the free bonds are present in the para positions. 5 and R 6 is attached to the two ortho positions of the free bond. In the above formula (2), the free bonds (the two bond positions to which the amino groups are attached) are preferably R 11 It is present at the meta or para position relative to (the linking group), but it is preferably present at the para position from the viewpoint of obtaining a polyimide having a highly linear main chain structure in order to reduce the thermal expansion coefficient. 5 and R 6 is attached to the two ortho positions of the free bond. R 11 represents a group selected from a single bond, -alkyl group (the number of carbon atoms in the alkyl group, n, is 1 to 6)-, -fluorene group, -O-, -S-, -SS-, -SO-, -SO2-, -CO-, -COO-, -NH-, -CONH-, -CON-alkyl group- (the number of carbon atoms in the alkyl group, n, is 1 to 6), and -CON-benzyl group-. In the above formula (3), the free bonds (the two bond positions to which the amino groups are bonded) are present at the 2-, 3-, 6-, or 7-positions, and R 5 and R6 is attached to the two ortho positions of the free bond. In the above formulas (1) to (3), R 7 ~R 10 is a straight-chain or branched alkyl group, alkoxy group (C is n=1 to 12) or alkoxyalkyl group (C is n=2 to 12) having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms.

[0036] As the diamine having a dibenzothiophene sulfone structure, for example, a diamine having an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, at the ortho position of the amino group is preferred, and among these, a diamine having a structure of the following formula (4) is preferred.

[0037] [ka]

[0038] In the present invention, (b-1) an aromatic diamine residue (Ar 1 In order to improve the crosslink density and achieve a low coefficient of thermal expansion, (A) the solvent-soluble polyimide preferably contains 20 mol % or more, 25 mol % or more, 30 mol % or more, 35 mol % or more, or even 40 mol % or more, and 90 mol % or less, 85 mol % or less, or even 80 mol % or less of all diamines constituting the solvent-soluble polyimide. It is preferable to contain (b-1) an aromatic diamine residue (Ar 1 If the amount of the diamine is less than 20 mol % of the total diamine, the crosslink density may decrease.

[0039] (b-2) Residue of an aromatic diamine having an indane structure In the present invention, an aromatic diamine residue having an indane structure (Ar 2 ) includes an amine residue having a structure represented by the following formula (5) or (6).

[0040] [ka]

[0041] In the above formula (5), R1 and R2 each represent an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkoxyalkyl group having 2 to 12 carbon atoms, and R1 and R2 are preferably bonded to the two ortho positions of the free bond (the bonding position of the amino group).

[0042] [ka]

[0043] In the above formula (6), R1, R2, and R3 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and preferably an alkyl group having 1 to 3 carbon atoms. Each of R4 and each of R5 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and preferably a hydrogen atom or a methyl group. Specific examples of the diamine of formula (6) include 5-amino-1-(4'-aminophenyl)-1,3,3-trimethylindan and 6-amino-1-(4'-aminophenyl)-1,3,3-trimethylindan. The (b-2) residue of an aromatic diamine having an indane structure is preferably a residue of an aromatic diamine having a phenylindane structure represented by the above formula (6).

[0044] In the present invention, (b-2) an aromatic diamine residue having an indane structure (Ar 2 In order to improve the crosslink density and achieve a low thermal expansion coefficient, it is preferable that the diamine (A) is contained in an amount of 10 mol % or more, 15 mol % or more, 20 mol % or more, 25 mol % or more, or even 30 mol % or more, and 95 mol % or less, 90 mol % or less, or even 85 mol % or less of all diamines constituting the solvent-soluble polyimide (A). It is preferable that the diamine (A) is contained in an amount of less than 10 mol %. If the amount is less than 10 mol %, the crosslink density tends to decrease.

[0045] In order to reduce the thermal expansion coefficient, it is preferable that the two amino groups substituted on the aromatic ring are substituted at the para-position relative to each other in all diamines including the aromatic diamine having an alkyl group at the ortho-position of the amino group (b-1) and the aromatic diamine having an indane structure (b-2). The aromatic diamine having the two amino groups substituted at the para-position relative to each other is preferably contained in an amount of 30 mol% or more, 40 mol% or more, or even 50 mol% or more, and 90 mol% or less, 80 mol% or less, or even 70 mol% or less of the total aromatic diamine.

[0046] In order to increase the transparency in the visible light region and to achieve both a low thermal expansion coefficient and solvent solubility, other diamines can be used in combination. Examples of such aromatic diamines include aromatic diamines having fluorine atoms or substituents containing fluorine atoms. Representative examples include 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, and 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane.

[0047] The (A) solvent-soluble polyimide may have a repeating unit composed of an aromatic tetracarboxylic dianhydride residue and a diamine residue other than those represented by the above general formulae [I] and [II].

[0048] (A) Method for synthesizing solvent-soluble polyimide The method for synthesizing the solvent-soluble polyimide may be a known method and is not particularly limited, but the solvent-soluble polyimide can be synthesized by using approximately equal amounts of the above-mentioned (a) alicyclic acid dianhydride and (b) diamine, and reacting them in an organic polar solvent in the presence of a catalyst and a dehydrating agent at 160 to 200° C. for several hours. Examples of the organic polar solvent that can be used include N-methylpyrrolidone (NMP), γ-butyrolactone, N,N'-dimethylacetamide, N,N'-dimethylformamide, dimethylsulfoxide, tetramethylurea, and tetrahydrothiophene-1,1-oxide.

[0049] The (A) solvent-soluble polyimide in the present invention is a block copolymer, and can be synthesized by carrying out a block copolymerization reaction as necessary. For example, it can be produced by a two-stage sequential addition reaction, in which a polyimide oligomer is synthesized from the above-mentioned (a) alicyclic acid dianhydride and (b) diamine in the first stage, and then a tetracarboxylic acid dianhydride and / or an aromatic diamine is further added in the second stage to carry out polycondensation to obtain a block copolymer polyimide.

[0050] As a catalyst for block copolymerization, a two-component acid-base catalyst utilizing the equilibrium reaction of lactones can be used to promote the dehydration imidization reaction. Specifically, a two-component catalyst of γ-valerolactone and pyridine or N-methylmorpholine is used. As shown in the formula below, as the imidization proceeds, water is generated, and the generated water participates in the equilibrium of lactones, becoming an acid-base catalyst and exhibiting catalytic action.

[0051] [ka]

[0052] The water produced by the imidization reaction is removed from the system by azeotropy with a dehydrating agent such as toluene or xylene that coexists in the polar solvent. When the reaction is completed, the water in the solution is removed, and the acid-base catalyst becomes γ-valerolactone and pyridine or N-methylmorpholine, which are removed from the system. In this way, a high-purity polyimide solution can be obtained.

[0053] Other two-component catalysts include oxalic acid or malonic acid and pyridine or N-methylmorpholine. In a reaction solution at 160 to 200°C, oxalates or malonates act as acid catalysts to promote the imidization reaction. A catalytic amount of oxalic acid or malonic acid remains in the generated polyimide solvent. When this polyimide solution is applied to a substrate and then heated to 200°C or higher to remove the solvent and form a film, the oxalic acid or malonic acid remaining in the polyimide is thermally decomposed as shown in the following formula and removed from the system as a gas.

[0054] [ka]

[0055] By the above method, it is possible to obtain a high-purity solvent-soluble polyimide (A). The oxalic acid-pyridine catalyst is more active than the valerolactone-pyridine catalyst, and can produce a high-molecular-weight polyimide in a short period of time.

[0056] The term "solvent-soluble" in the present invention is used for the organic polar solvent used in the synthesis of polyimide and the solvent used in the film described below, and means that the polyimide is dissolved in an amount of 5 g or more in 100 g of solvent. Here, examples of the solvent include polar solvents such as N-methyl-2-pyrrolidone, γ-butyrolactone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, sulfolane, and tetramethylurea.

[0057] The (A) solvent-soluble polyimide synthesized as described above can be used in the form of a solution dissolved in the above organic polar solvent or a solvent used in the film described below so that the solid content is, for example, 10 to 30% by weight. The molecular weight of the (A) solvent-soluble polyimide is preferably 10,000 to 400,000 as a weight average molecular weight converted into polystyrene. Within this range, good solvent solubility, film properties, and insulating properties can be achieved. The appropriate viscosity of the (A) solvent-soluble polyimide is preferably 2 to 10 Pa·s / 25°C when the solid content is 20 to 40% by weight. The glass transition temperature (Tg) (measured by TMA measurement method) of the solvent-soluble polyimide is preferably 200°C or higher, more preferably 250°C or higher.

[0058] The concentration of the solvent-soluble polyimide (A) in the solution is preferably 5 to 50% by weight, more preferably 10 to 40% by weight. The polyimide obtained by the direct imidization reaction using the catalyst system consisting of the lactone and the base can be obtained in the form of a solution dissolved in a polar solvent, and the polyimide concentration can be set within the above-mentioned preferred range, so that the produced polyimide solution can be used as it is.

[0059] The produced polyimide solution can be further diluted, if desired, with a diluent, such as, but not limited to, a solvent that does not significantly impair the solubility, such as dioxane, dioxolane, N-methyl-2-pyrrolidone, γ-butyrolactone, cyclohexanone, cyclopentanone, propylene glycol monomethyl ether acetate, methyl lactate, anisole, methyl benzoate, ethyl acetate, etc.

[0060] (B) Diazide compounds In the present invention, a diazide compound (B) is added to the photosensitive polyimide resin composition as another essential component. The diazide compound (B) is a photocrosslinking agent for interpolymer crosslinking of the solvent-soluble polyimide (A). By using the diazide compound (B) in combination with the solvent-soluble polyimide (A) having a specific structure of the present invention, there is an effect of significantly improving the exposure and developability.

[0061] (B) Examples of the diazide compound include 4,4'-diazidobenzalacetophenone, 2,6-di(4'-azidobenzal)cyclohexanone, 2,6-di(4'-azidobenzal)-4-methylcyclohexanone, 2,6-di(4'-azidobenzal)-4-ethylcyclohexanone, 2,6-di(4'-azidobenzal)-4-t-amylcyclohexanone, 4,4'-diazidodiphenylsulfone, 4,4'-diazidodiphenylether, 4,4'-diazidophenylsulfide, 4,4'-diazidodiphenylmethane, etc. Among these, those having a diazidobenzalcyclohexanone structure are preferred, and from the viewpoint of crosslinking property and storage stability, 2,6-di(4'-azidobenzal)-4-ethylcyclohexanone is particularly excellent.

[0062] The (B) diazide compound is preferably contained in the photosensitive polyimide resin composition in an amount of 2.0 to 150 parts by weight, more preferably 5.0 to 100 parts by weight, and particularly preferably 10.0 to 80 parts by weight, per 100 parts by weight of the (A) solvent-soluble polyimide. If the amount is less than 2.0 parts by weight, the crosslink density tends to decrease, and if the amount is more than 150 parts by weight, the film properties tend to decrease. In order to complement the crosslinking property, a diazirine compound, a maleimide compound, or a bismaleimide compound may be used in combination.

[0063] The photosensitive polyimide resin composition of the present invention, which contains the above-mentioned (A) solvent-soluble polyimide and the above-mentioned (B) diazide compound, can be used as a negative-type photosensitive polyimide resin composition because the (A) solvent-soluble polyimide in the exposed area undergoes a photocrosslinking reaction upon exposure, and the exposed area remains even after development treatment.

[0064] The photosensitive polyimide resin composition of the present invention has poor light transmittance at low wavelengths, and therefore, in particular in the case of thick-film specifications, the pattern shape is prone to the reverse taper seen in negative solvent development. In order to improve this, it has been found that it is also effective to use photosensitive monomers or polymers with different photosensitive crosslinking length methods in combination. Among them, it has been found that the combination of (C) epoxy resin and (D) photobase generator, which have excellent compatibility with the photosensitive polyimide resin composition, is particularly effective as a component of the photosensitive polyimide resin composition of the present invention.

[0065] (C) Epoxy resin The epoxy resin (C) is not particularly limited and can be selected based on the reactivity with the photobase generator and the compatibility with the photosensitive polyimide resin composition. Examples of the epoxy resin include phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, triazine skeleton-containing epoxy resin, fluorene skeleton-containing epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, crystalline epoxy resin, bisphenol A type epoxy resin, etc., and these polymer epoxy resins can also be used. The content of the epoxy resin (C) in the photosensitive polyimide resin composition is preferably 2 to 50 parts by weight, and most preferably 2 to 20 parts by weight, based on 100 parts by weight of the solvent-soluble polyimide (A).

[0066] (D) Photobase generator (D) Photobase generators are components that generate anions (bases) when irradiated with ultraviolet light, and are broadly classified into non-ionic and ionic types. Non-ionic types include those that absorb light and generate primary amines, secondary amines, imidazoles, etc., while ionic types include those that generate strong organic bases such as amidines, guanidines, and phosphazenes. As the (D) photobase generator, those which generate a primary amine or a secondary amine in the reaction with the (C) epoxy resin are less likely to cause a chain reaction, and therefore, preferred are non-ionic ones which generate imidazole, and ionic ones which generate amidine, guanidine, or the like.

[0067] As the photobase generator (D) in the present invention, commercially available products can be used, such as WPBG-018, WPBG-140, WPBG-266, WPBG-300, WPBG-345, WPBG-027, and WPBG-165 (all manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). The content of the photobase generator (D) in the photosensitive polyimide resin composition is preferably 0.1 to 3% by weight relative to the epoxy resin (C).

[0068] (Photosensitizer) The photosensitive polyimide resin composition of the present invention can contain a photosensitizer to enhance the sensitivity of pattern resolution in order to adapt it to each final use. As the photosensitizer, those that act on the long wavelength side (>350 nm) are particularly preferable. As the photosensitizer, for example, anthracene-based sensitizers, thioxanthone-based sensitizers, etc. are mentioned. The content of the photosensitizer is preferably about 0.05 to 2% by weight based on the photosensitive polyimide resin composition.

[0069] Specific examples of the anthracene-based sensitizer include 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-diisopropoxyanthracene, 9,10-dibutoxyanthracene, 9,10-dipentyloxyanthracene, 9,10-dihexyloxyanthracene, 9,10-bis(2-methoxyethoxy)anthracene, 9,10-bis(2-ethoxyethoxy)anthracene, 9,10-bis(2-butoxyethoxy)anthracene, and 9,10-bis(3-butoxypropoxy). ) anthracene, 2-methyl- or 2-ethyl-9,10 dimethoxyanthracene, 2-methyl- or 2-ethyl-9,10-diethoxyanthracene, 2-methyl- or 2-ethyl-9,10-dipropoxyanthracene, 2-methyl- or 2-ethyl-9,10-diisopropoxyanthracene, 2-methyl- or 2-ethyl-9,10-dibutoxyanthracene, 2-methyl- or 2-ethyl-9,10-dipentyloxyanthracene, 2-methyl- or 2-ethyl-9,10-dihexyloxyanthracene, and the like. Commercially available anthracene sensitizers can be used, such as "Anthracure UVS-1331", "Anthracure UVS-1101" and "Anthracure UVS-1221" (all manufactured by Kawasaki Chemical Industries, Ltd.).

[0070] Examples of thioxanthone sensitizers include 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, and chloropropoxythioxanthone. Commercially available products can be used as the thioxanthone sensitizers. Examples of commercially available products include "KAYACURE DETX-S" (manufactured by Nippon Kayaku Co., Ltd.), "Speedcure ITX", "Speedcure DETX", and "Speedcure CPTX" (all manufactured by LAMBSON).

[0071] (Other additives) The photosensitive polyimide resin composition of the present invention may contain modifiers that are added to ordinary photosensitive polyimide resin compositions, such as coupling agents, plasticizers, film-forming resins, surfactants, stabilizers, spectral sensitivity regulators, etc. In particular, when the adhesion of the polyimide to the substrate is poor, coupling agents, particularly vinyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltrialkoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-trimethoxysilylpropylsuccinic anhydride, hexamethyldisiloxane ... By adding a silane coupling agent such as disilazane, 1,3-bis(3-aminopropyl)tetramethyldisiloxane, N-[3-(triethoxysilyl)propyl]phthalamic acid, 7-octenyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, N-2-(aminoethyl)-8-aminooctyltrimethoxysilane, 8-methacryloxyoctyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, 3-trimethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-(1-phenylethylidene)-3-(triethoxysilyl)-1-propylamine, or N-(1-phenylethylidene)-3-(trimethoxysilyl)-1-propylamine, the adhesion to the substrate can be improved. In this case, the amount of the silane coupling agent added is preferably 0.1 to 5% by weight of the photosensitive polyimide resin composition. If the adhesion is not good even after adding the silane coupling agent, it is effective to perform surface treatment of the substrate using the coupling agent.

[0072] In addition, when a substrate made of copper or a copper alloy is used, an azole compound can be added to the photosensitive polyimide resin composition in order to suppress discoloration of the substrate. Examples of the azole compound include 1H-benzotriazole, tolyltriazole, 5-methyl-1H-benzotrial, 4-methyl-1H-benzotrial, 5-carboxy-1H-benzotrial, and 4-carboxy-1H-benzotrial. In this case, the amount of the azole compound added is preferably 0.1 to 1% by weight of the photosensitive polyimide resin composition.

[0073] Furthermore, in order to suppress discoloration on copper, a hindered phenol compound can be blended into the photosensitive polyimide resin composition. Examples of the hindered phenol compound include 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-5-ethyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, and 1,3,5-tris(4-triethylmethyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione. In this case, the amount of the hindered phenol compound added is preferably 0.1 to 2% by weight of the photosensitive polyimide resin composition. Other resins that can be used in combination include polyarylate resins and polyethersulfone resins.

[0074] The photosensitive polyimide resin composition of the present invention can be in the form of a solution suitable for application onto a substrate, in which case the solvent can be a polar solvent such as N-methyl-2-pyrrolidone, γ-butyrolactone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, sulfolane, or tetramethylurea, which is used as a solvent for imidization reactions.

[0075] [Method for producing photosensitive polyimide patterns] A photosensitive polyimide pattern can be produced on a substrate by using the photosensitive polyimide resin composition containing the above-mentioned components. Specifically, the photosensitive polyimide pattern can be produced by a method including the steps of: (1) forming a resin layer on a substrate by applying the above-mentioned photosensitive polyimide resin composition of the present invention on the substrate; (2) exposing the resin layer; (3) developing the exposed resin layer to form a photosensitive polyimide pattern for an insulating material of an electronic component, and a passivation film, a buffer coat film, an interlayer insulating film, etc. in a semiconductor package; and (4) completing the photosensitive polyimide pattern as a permanent insulating film by heat treatment.

[0076] A typical embodiment of each step will be described below. (1) forming a resin layer on a substrate by applying a photosensitive resin composition onto the substrate; In this step, the photosensitive resin composition of the present invention is applied onto a substrate such as a silicon wafer, a metal substrate, a ceramic substrate, an organic substrate, etc., and then dried as necessary to form a resin layer. As the application method, a method that has been conventionally used for applying a photosensitive resin composition, such as a method of applying with a spin coater, a bar coater, a blade coater, a curtain coater, a screen printer, etc., or a method of spray application with a spray coater, etc. can be used.

[0077] If necessary, the coating film made of the photosensitive resin composition can be dried. As the drying method, air drying, heat drying with an oven or a hot plate, vacuum drying, etc. can be used. Specifically, when air drying or heat drying is performed, drying can be performed under conditions of 20 to 140°C for 1 to 30 minutes. There is no limitation to this range as long as it does not impair the various properties of the photosensitive resin composition of the present invention.

[0078] (2) Step of exposing the resin layer to light: In this step, the resin layer formed in the above step (1) is exposed to an ultraviolet light source or the like through a photomask or reticle having a pattern, or directly, using an exposure device such as a contact aligner, mirror projection, or stepper. Thereafter, for the purpose of improving photosensitivity, etc., post-exposure baking and / or pre-development baking may be performed at any combination of temperature and time, as necessary. The range of baking conditions is preferably a temperature of 40 to 120° C. and a time of 10 to 240 seconds, but is not limited to this range as long as it does not impair the various properties of the photosensitive resin composition of the present invention.

[0079] (3) A process of developing the exposed resin layer to form a photosensitive polyimide pattern: In this step, the unexposed portion of the photosensitive resin layer after exposure is developed and removed. As the development method, any method can be selected from conventionally known photoresist development methods, such as the rotary spray method, the paddle method, and the immersion method accompanied by ultrasonic treatment. After development, post-development baking may be performed at any combination of temperature and time as necessary for the purpose of adjusting the shape of the photosensitive polyimide pattern.

[0080] The developer used for development is preferably a good solvent for the photosensitive resin composition, or a combination of the good solvent and a poor solvent. For example, the good solvent is preferably N-methylpyrrolidone, N-cyclohexyl-2-pyrrolidone, N,N-dimethylacetamide, cyclopentanone, cyclohexanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, etc. The poor solvent is preferably toluene, xylene, methanol, ethanol, isopropyl alcohol, ethyl lactate, propylene glycol methyl ether acetate, etc. When a good solvent and a poor solvent are used in combination, it is preferable to adjust the ratio of the poor solvent to the good solvent according to the solubility of the polymer in the photosensitive resin composition. In addition, two or more solvents, for example, several types, can be used in combination for each of the good solvent and the poor solvent.

[0081] (4) A process of completing the photosensitive polyimide pattern as a permanent insulating film by heat treatment: In this process, the photosensitive polyimide pattern obtained by the above development is heated to complete it as a permanent insulating film. That is, unlike the polyamic acid type, since imidization has already been completed, it can be completed as a permanent insulating film by removing the residues such as the solvent. As the method of heat curing, various methods can be selected, such as using a hot plate, an oven, or a temperature-elevating oven that can set a temperature program. Heating is performed under conditions sufficient to evaporate the contained solvent, for example, at 150 to 300°C for about 30 minutes to 2 hours. The atmospheric gas during heating may be air, or an inert gas such as nitrogen or argon may be used.

[0082] The photosensitive polyimide pattern thus formed can be used as an interlayer insulating film, a passivation film or a surface protective film for a semiconductor package, an electronic element, a display element or an organic multilayer wiring board. EXAMPLES

[0083] The present invention will be described in detail below using examples, but the present invention is not limited to these.

[0084] (Synthesis of block copolymer polyimide) Synthesis Example 1 A glass separable three-neck flask was equipped with a stirrer, a nitrogen inlet tube, and a cooling tube equipped with a water receiver. 14.39 g (0.046 mol) of 4,4-oxydiphthalic anhydride (hereinafter referred to as ODPA), 9.10 g (0.046 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (hereinafter referred to as CBDA), 21.64 g (0.079 mol) of 3,7-diamino-2,8-dimethyldibenzothiophenesulfone (hereinafter referred to as TSN) (an aromatic diamine having an alkyl group at the ortho position of the amino group), 1.9 g (0.019 mol) of valerolactone, 3.0 g (0.04 mol) of pyridine, 125 g of NMP, and 50 g of toluene were charged and stirred at room temperature under a nitrogen atmosphere at 180 rpm for 30 minutes, and then heated to 180° C. and stirred for 1.5 hours. During the reaction, the toluene-water azeotrope was removed. After cooling to room temperature, 21.32g (0.098mol) of pyromellitic anhydride (hereinafter referred to as PMDA), 34.17g (0.107mol) of 2,2-bis(trifluoromethyl)benzidine (hereinafter referred to as TFMB), and 400g of NMP were added and stirred at room temperature for 30 minutes, and then the temperature was raised to 180°C and heated and stirred for 1 hour. The reaction was terminated by heating and stirring at 180°C for 5 hours while removing the water-toluene azeotropic reflux from the system. A block copolymer polyimide solution with a solid content of 15% by weight was obtained.

[0085] Synthesis Example 2 A glass separable three-neck flask was equipped with a stirrer, a nitrogen inlet tube, and a cooling tube equipped with a water receiver. 14.39 g (0.046 mol) of 4,4-oxydiphthalic anhydride (hereinafter referred to as ODPA), 9.10 g (0.046 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (hereinafter referred to as CBDA), 21.64 g (0.079 mol) of 3,7-diamino-2,8-dimethyldibenzothiophenesulfone (hereinafter referred to as TSN) (an aromatic diamine having an alkyl group at the ortho position of the amino group), 1.9 g (0.019 mol) of valerolactone, 3.0 g (0.04 mol) of pyridine, 125 g of NMP, and 50 g of toluene were charged and stirred at room temperature under a nitrogen atmosphere at 180 rpm for 30 minutes, and then heated to 180° C. and stirred for 1.5 hours. During the reaction, the toluene-water azeotrope was removed. After cooling to room temperature, 15.33g (0.049 mol) of ODPA, 9.69g (0.049 mol) of CBDA, 34.17g (0.107 mol) of 2,2-bis(trifluoromethyl)benzidine (hereinafter referred to as TFMB), and 420g of NMP were added and stirred at room temperature for 30 minutes, and then the temperature was raised to 180°C and heated and stirred for 1 hour. The reaction was terminated by heating and stirring at 180°C for 5 hours while removing the water-toluene azeotropic reflux from the system. A block copolymer polyimide solution with a solid content of 15% by weight was obtained.

[0086] Synthesis Example 3 A three-necked separable glass flask was equipped with a stirrer, a nitrogen inlet tube, and a cooling tube equipped with a water receiver. 14.39 g (0.046 mol) of 4,4-oxydiphthalic anhydride (hereinafter referred to as ODPA), 9.75 g (0.046 mol) of trans-1,2,3,4-cyclopentanetetracarboxylic dianhydride, 21.64 g (0.079 mol) of 3,7-diamino-2,8-dimethyldibenzothiophenesulfone (hereinafter referred to as TSN) (an aromatic diamine having an alkyl group at the ortho position of the amino group), 1.9 g (0.019 mol) of valerolactone, 3.0 g (0.04 mol) of pyridine, 130 g of NMP, and 50 g of toluene were charged and stirred at room temperature under a nitrogen atmosphere at 180 rpm for 30 minutes, and then heated to 180° C. and stirred for 1.5 hours. During the reaction, the toluene-water azeotrope was removed. After cooling to room temperature, 21.32g (0.098mol) of pyromellitic anhydride (hereinafter referred to as PMDA), 34.17g (0.107mol) of 2,2-bis(trifluoromethyl)benzidine (hereinafter referred to as TFMB), and 400g of NMP were added and stirred at room temperature for 30 minutes, and then the temperature was raised to 180°C and heated and stirred for 1 hour. The reaction was terminated by heating and stirring at 180°C for 5 hours while removing the water-toluene azeotropic reflux from the system. A block copolymer polyimide solution with a solid content of 15% by weight was obtained.

[0087] Synthesis Example 4 A three-necked separable glass flask was equipped with a stirrer, a nitrogen inlet tube, and a cooling tube equipped with a water receiver. 14.39g (0.046 mol) of 4,4-oxydiphthalic anhydride (hereinafter referred to as ODPA), 9.10g (0.046 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (hereinafter referred to as CBDA), 21.04g (0.079 mol) of 5-amino-1-(4'-aminophenyl)-1,3,3-trimethylindane (aromatic diamine containing a phenylindane structure), 1.9g (0.019 mol) of valerolactone, 3.0g (0.04 mol) of pyridine, 125g of NMP, and 50g of toluene were charged and stirred at room temperature under a nitrogen atmosphere at 180 rpm for 30 minutes, and then heated to 180°C and stirred for 1.5 hours. During the reaction, the toluene-water azeotrope was removed. After cooling to room temperature, 21.32g (0.098mol) of pyromellitic anhydride (hereinafter referred to as PMDA), 34.17g (0.107mol) of 2,2-bis(trifluoromethyl)benzidine (hereinafter referred to as TFMB), and 400g of NMP were added and stirred at room temperature for 30 minutes, and then the temperature was raised to 180°C and heated and stirred for 1 hour. The reaction was terminated by heating and stirring at 180°C for 5 hours while removing the water-toluene azeotropic reflux from the system. A block copolymer polyimide solution with a solid content of 15% by weight was obtained.

[0088] Comparative Synthesis Example 1 A glass separable three-neck flask was equipped with a stirrer, a nitrogen inlet tube, and a cooling tube equipped with a water receiver. 64.45g (0.2 mol) of 3,4,3',4'-benzophenonetetracarboxylic dianhydride (hereinafter referred to as BTDA), 29.23g (0.1 mol) of 1,3-bis(3-aminophenoxy)benzene, 1.5g (0.015 mol) of valerolactone, 2.4g (0.03 mol) of pyridine, 200g of NMP, and 30g of toluene were charged and stirred at room temperature under a nitrogen atmosphere at 200 rpm for 30 minutes, and then heated to 180°C and stirred for 1 hour. During the reaction, the toluene-water azeotrope was removed. After cooling to room temperature, 48.33g (0.15 mol) of BTDA, 44.57g (0.25 mol) of 2,4-diethyl-6-methyl-1,3-benzenediamine (an aromatic diamine having an alkyl group at the ortho position relative to the N-), 360g of NMP, and 90g of toluene were added and stirred at room temperature for 30 minutes, and then the temperature was raised to 180°C and heated and stirred for 1 hour. The reaction was terminated by heating and stirring at 180°C for 2 hours and 30 minutes while removing the water-toluene azeotropic reflux from the system. The obtained product was diluted with NMP to obtain a block copolymer polyimide solution with a solid content of 20% by weight.

[0089] (Preparation of Photosensitive Polyimide Resin Composition) In the following examples and comparative examples, "parts" means "parts by weight".

[0090] Examples 1 to 4 To 500 parts of the block copolymer polyimide solutions (solid content 15 wt%) of Synthesis Examples 1 to 4, 40 parts of 2,6-di(4'-azidobenzal)-4-ethylcyclohexanone and 0.06 parts of 9,10-dibutoxyanthracene were added and dissolved in NMP to obtain a photosensitive resin composition with a solid content of 20 wt%.

[0091] Examples 5 to 8 500 parts of the block copolymer polyimide solution (solid content 15% by weight) of Synthesis Examples 1 to 4 were added with 40 parts of 2,6-di(4'-azidobenzal)-4-ethylcyclohexanone, 0.06 parts of 9,10-dibutoxyanthracene, 0.75 parts of 3-glycidoxypropylmethyldimethoxysilane, 0.075 parts of 5-methyl-1H-benzotrial, and 0.75 parts of 1,3,5-tris(4-triethylmethyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, and dissolved in NMP to obtain a photosensitive resin composition with a solid content of 20%.

[0092] Example 9 500 parts of the block copolymer polyimide solution (solid content 15% by weight) of Synthesis Example 1 was added with 40 parts of 2,6-di(4'-azidobenzal)-4-ethylcyclohexanone, 0.06 parts of 9,10-dibutoxyanthracene, 0.75 parts of 3-glycidoxypropylmethyldimethoxysilane, 0.075 parts of 5-methyl-1H-benzotrial, 0.75 parts of 1,3,5-tris(4-triethylmethyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 4 parts of TEPIC-VL (trifunctional epoxy: Nissan Chemical Industries, Ltd.), and 0.075 parts of WPBG (photobase generator: Fujifilm Wako Pure Chemical Industries, Ltd.), and dissolved in NMP to obtain a photosensitive resin composition with a solid content of 20%.

[0093] Comparative Example 1 20 parts of 2,6-di(4'-azidobenzal)-4-ethylcyclohexanone, 1 part of 9,10-dibutoxyanthracene, 1 part of 3-glycidoxypropylmethyldimethoxysilane, 0.1 parts of 5-methyl-1H-benzotrial, and 1 part of 1,3,5-tris(4-triethylmethyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione were added to 500 parts of the block copolymer polyimide solution (solid content 20% by weight) of Synthesis Comparative Example 1, and dissolved in methyl benzoate to obtain a photosensitive resin composition with a solid content of 25%.

[0094] (Performance evaluation of polyimide resin composition) 1. Mechanical strength, thermal expansion coefficient and 5% thermal weight loss temperature The resin compositions of the above-mentioned Examples and Comparative Examples (Examples 1 to 3 are resin compositions that had been previously treated with a silane coupling agent) were spin-coated onto a 6-inch silicon wafer so that the film thickness after final drying would be 15 to 17 μm, and the wafer was pre-baked at 90° C. for 360 seconds. After that, the wafer was exposed to a high-pressure mercury lamp at an i-line equivalent of 2,500 mJ / cm 2 After exposure to light of all wavelengths, the film was immersed in an NMP solution (cyclopentanone solution in the comparative example) for 120 seconds, and then dried by heating at 250° C. (or 200° C.) for 90 minutes to prepare a dried resin film. This dry resin film was peeled off from the wafer with hydrofluoric acid or the like to prepare a test sample for measuring mechanical strength, thermal expansion coefficient, and 5% thermal weight loss temperature.

[0095] 2. Adhesion strength The dried resin film formed on the silicon wafer prepared above is used. (1) Using a cutter knife, make 11 cuts reaching down to the base material on the test surface to create 100 grids. Use a cutter guide to make the cuts 1 mm apart. (2) Firmly press cellophane tape (registered trademark) onto the grid, then pull off the end of the tape at a 45° angle in one go, and evaluate the state of the grid by comparing it with the standard diagram. Determine the adhesion strength after 240 hours under normal conditions and HAST (80℃ x 85% RH).

[0096] 3. Film Remaining Rate The resin compositions obtained in each of the Examples and Comparative Examples (Examples 1 to 3 are resin compositions that had been previously treated with a silane coupling agent) were spin-coated onto a 6-inch silicon wafer so that the film thickness after final drying would be 5 to 7 μm and 10 to 12 μm, respectively, and the wafers were pre-baked at 90° C. for 240 seconds and 90° C. for 300 seconds, after which the thickness (t1) was measured with a film thickness gauge. Next, a high-pressure mercury lamp was used to measure the thickness of the wafer at 1,000 (or 2,500) mJ / cm in terms of i-line. 2 After exposure to all wavelengths, the film is immersed in an NMP solution (cyclopentanone solution in the comparative example) for 120 seconds, and then the thickness (t2) is measured with a film thickness gauge. The film is then dried by heating at 250°C (or 200°C) for 90 minutes, and the thickness (t3) is then measured with a film thickness gauge. From this value, t2 / t 1、 The ratio t3 / t1 and the ratio t3 / t2 were calculated to obtain the remaining film ratio.

[0097] 4. Exposure and development properties The pattern evaluation was carried out by the following method. (1) Resolution The resin compositions obtained in each of the above Examples and Comparative Examples (Examples 1 to 3 are resin compositions that had been previously treated with a silane coupling agent) were dropped onto a 6-inch silicon wafer, spin-coated for 30 seconds, and then pre-baked on a hot plate at 90°C for 240 seconds. At this time, the coating rotation was adjusted so that the film thickness after baking would be approximately 6 to 8 μm. Next, exposure was performed using a high-pressure mercury lamp. The exposure dose measured with i-line was 1,000 mJ / cm. 2 Then, the substrate was developed with an NMP solution (cyclopentanone solution in the comparative example), rinsed, and then dried by heating at 250°C (or 200°C) for 90 minutes. The resolution was determined as the smallest resolution among L / S=5 / 5, 10 / 10, 15 / 15, 20 / 20, 30 / 30, 50 / 50μm and square via hole patterns of 10, 15, 20, 30, 40, and 50μm.

[0098] (2) Pattern edge residue, cracks Pattern processing was performed in the same manner as in (1) above, and first, the film surface after development was visually observed for abnormalities. Next, a 15 μm square via hole pattern was observed with an optical microscope, and if there was a crack at the corner of the pattern, it was judged to have a crack. Furthermore, the pattern edge of L / S=15 / 15 was observed, and if there was a development residue, it was judged to have a residue.

[0099] The evaluation results of the resin compositions obtained in the above Examples and Comparative Examples are shown in Tables 1 and 2 below.

[0100] [Table 1]

[0101] [Table 2]

[0102] From the results of Tables 1 and 2, it can be seen that the composition of Comparative Example 1 using a polyimide having only aromatic dianhydride residues and no alicyclic dianhydride residues as the acid dianhydride residues (a) had a thermal expansion coefficient of 56 ppm / °C, an elastic modulus of 2.5 GPa, and a breaking strength of 115 MPa, whereas the compositions of Examples 1 to 9 using polyimides having alicyclic dianhydride residues (a) achieved a thermal expansion coefficient of 18 to 30 ppm / °C, an elastic modulus of 4.0 to 4.7 GPa, and a breaking strength of 140 to 173 MPa. It can also be seen that the compositions of Examples 1 to 9 maintained high adhesion strength, high film remaining rate, and good exposure developability. These results show that a composition containing a solvent-soluble polyimide having (a) an alicyclic acid dianhydride residue and (b) a specific diamine residue in the same repeating unit, and a diazide compound, has solubility in the developer during development and insolubility in the developer after photocrosslinking, and can achieve good film properties and high sensitivity, as well as a low thermal expansion coefficient and excellent mechanical strength. [Industrial Applicability]

[0103] The photosensitive polyimide resin composition of the present invention has solubility in a developer during development and insolubility in a developer after photocrosslinking, and can achieve good film properties and high sensitivity. In addition, it has a low thermal expansion coefficient and excellent mechanical strength. Therefore, it is useful for producing, for example, semiconductor packages such as FO-WLP, FO-PLP, WLP, etc.; thin-film magnetic elements such as thin-film magnetic heads, thin-film inductors, and common-mode choke coils; electronic elements; display elements such as TFT liquid crystal elements, color filter elements, and organic EL elements; and organic multilayer wiring boards, and can be suitably used in the field of photosensitive materials.

Claims

1. A photosensitive polyimide resin composition comprising a solvent-soluble polyimide and a diazide compound as essential components, wherein the solvent-soluble polyimide is a block copolymer having, in the same repeating unit, (a) an alicyclic acid dianhydride residue, and (b) a residue of at least one diamine selected from the group consisting of an aromatic diamine having an alkyl group at the ortho-position of an amino group and an aromatic diamine having an indane structure.

2. 2. The resin composition according to claim 1, wherein the solvent-soluble polyimide has (b) a residue of an aromatic diamine having an alkyl group at the ortho position of an amino group, and the two amino groups of the aromatic diamine are located at the para position of a benzene ring relative to each other.

3. 2. The resin composition according to claim 1, wherein the solvent-soluble polyimide (b) has a residue of an aromatic diamine having an alkyl group at the ortho position of an amino group, the aromatic diamine has two benzene rings linked by a linking group, and the two amino groups of the aromatic diamine are present at the para position to the linking group.

4. The resin composition according to any one of claims 1 to 3, wherein the (a) alicyclic acid dianhydride residue is a residue of 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride.

5. The resin composition according to any one of claims 1 to 4, wherein the residue of the at least one diamine (b) is a residue of 3,7-diamino-2,8-dimethyldibenzothiophene sulfone.

6. The resin composition according to any one of claims 1 to 5, wherein the diazide compound is 2,6-di(4'-azidobenzal)-4-ethylcyclohexanone.

7. 7. The resin composition according to claim 1, wherein the content of the diazide compound is 5.0 to 100 parts by weight based on 100 parts by weight of the solvent-soluble polyimide.

8. The resin composition according to any one of claims 1 to 7, wherein the photosensitive polyimide resin composition has a thermal expansion coefficient of 20 ppm / °C or less.

9. The resin composition according to any one of claims 1 to 8, wherein the photosensitive polyimide resin composition further contains an epoxy resin and a photobase generator.

10. The resin composition according to any one of claims 1 to 9, wherein the photosensitive polyimide resin composition is a negative-tone solvent-developable composition.

11. A method for forming a pattern, comprising exposing a substrate coated with the resin composition according to any one of claims 1 to 10 to ultraviolet light and developing and removing unexposed areas.

12. A semiconductor package, a magnetic element, a display element, or an organic multilayer wiring board having an interlayer insulating film, a passivation film, or a surface protective film formed using the resin composition according to any one of claims 1 to 10.

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