JP2012141447A - Photosensitive polyimide precursor and photosensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive polyimide precursor having a small coefficient of thermal expansion and residual stress, excellent adhesiveness to a copper substrate or the like, and high fracture strength of a resin produced from the precursor, and to provide a photosensitive resin composition.SOLUTION: The photosensitive polyimide precursor has a repeating unit (1) obtained by polymerization condensation of a tetracarboxylic acid and an aromatic diamine and has an actinic ray-functional group at both terminals. The photosensitive polyimide precursor contains an aromatic tetracarboxylic acid having a rigid structure by 70 to 100 mol% with respect to the whole molar number of the tetracarboxylic acid. The aromatic diamine contains a thiophene-containing aromatic diamine and an aromatic diamine with a rigid structure by a molar ratio of 3:97 to 30:70. The actinic ray functional group comprises a phenyl amino group having a carbon-carbon double bond or a dicarboxyphenylcarbonyl group having a carbon-carbon double bond as an ester. The photosensitive resin composition contains the above precursor.

Description

  The present invention can form a polyimide resin film having a small coefficient of thermal expansion and residual stress, excellent adhesion to a copper substrate, copper wiring, etc., and having a high breaking strength and breaking elongation. When formed, the present invention relates to a photosensitive polyimide precursor that generates a small amount of warpage in a silicon wafer, and a photosensitive resin composition containing the photosensitive polyimide precursor.

In recent years, a photosensitive polyimide resin excellent in electrical characteristics, mechanical characteristics, and heat resistance is suitably used as a photosensitive resin composition for forming a surface protective film and an interlayer insulating film of a semiconductor element.
However, a film made of polyimide resin (polyimide resin film) has the following problems. That is, the thermal expansion coefficient of the polyimide resin film is generally 20 ppm / ° C. or higher. On the other hand, the thermal expansion coefficient of the metal substrate is usually 20 ppm / ° C. or less, and the thermal expansion coefficient of the silicon wafer is about 3 to 4 ppm / ° C. As described above, the thermal expansion coefficient of the metal wiring and various substrates is generally smaller than that of the polyimide resin film.
When a polyimide resin film is formed on a substrate, even if there is a large difference in the coefficient of thermal expansion between the substrate and the polyimide resin film, cracks and wiring occur due to heating and heat generation during the manufacturing process and use of semiconductor elements. There is a risk of disconnection, warping of the substrate, and the like. Further, when the residual stress of the polyimide resin film is large, the same problem is likely to occur. In particular, with the recent increase in the size of silicon wafers (for example, a substrate having a diameter of 300 mm), warping of the substrate due to stress caused by a passivation film formed from a polyimide resin has become a major problem.
As described above, manufacturing of a multilayer circuit board using a polyimide resin film as an insulating film is also being studied. In a semiconductor element using an extremely thin silicon wafer (for example, a board having a thickness of 50 μm or less), the reduction of the warpage of the board is not achieved. It has become one of the most important issues.

In addition, recently encapsulated elements such as thin silicon power semiconductor elements with a maximum operating temperature of 175 ° C. or higher, high-voltage next-generation power semiconductor elements (using SiC or GaN as a semiconductor substrate), etc. The insulating film is required to have characteristics such as higher heat resistance, high temperature adhesion, and high dielectric breakdown voltage.
Furthermore, in device wiring materials, switching from conventional aluminum wiring to copper wiring is progressing, but conventional photosensitive polyimides generally have difficulties in adhesion to copper, and improvements are required.

  As a solution to these problems, the surface of the semiconductor element is covered with a polyimide resin film having a low coefficient of thermal expansion, and the thermal stress generated at the interface between the substrate and the insulating film is alleviated, so that the semiconductor element is used or manufactured. Attempts have been made to suppress cracks in the insulating film and warpage of the substrate.

  For example, Patent Document 1 has a repeating unit formed from a polycondensation product of tetracarboxylic acid or its acid anhydride and diamine in a main chain on a circuit formed on a silicon wafer. It is disclosed to form a photosensitive polyimide precursor having an actinic functional group at the terminal. This document also describes that the thermal expansion coefficient of the polyimide resin film thus formed is preferably 20 ppm / ° C. or less.

  On the other hand, Non-Patent Document 1 reports the presence of a hardly-developable solubilized layer on the film surface, which is considered to be caused by the surface bleed of the crosslinking aid at the time of pattern formation when using a silicon substrate and photosensitive polyimide in Patent Document 1. ing. Similarly, when the photosensitive polyimide resin composition disclosed in Patent Document 1 is used, if a triethylene glycol diacrylate that is a crosslinking aid is used, a hardly soluble layer during development exists on the pattern surface. There is a problem that the development time becomes long in order to remove this layer. Exposure to a developer for a long time is not preferable because the film characteristics deteriorate. This is particularly true in pattern formation on a copper substrate (copper wiring) that has a problem in adhesion.

JP 2004-285129 A

Master's thesis, Kumamoto University Graduate School of Natural Science, February 2005 (Synthesis and Evaluation of Photosensitive Low Thermal Expansion Polyimide)

  The present invention has been made in view of the above-described conventional technology. A polyimide resin film having a low coefficient of thermal expansion and residual stress, excellent adhesion to a copper substrate, a copper wiring, and the like, and a large breaking strength and breaking elongation. A photosensitive polyimide precursor that can be formed and has a small warp generated on the silicon wafer when a film is formed on the silicon wafer, and a polyimide resin excellent in copper substrate adhesion that does not form a poorly soluble layer during development. It aims at providing the photosensitive resin composition which can form a film | membrane.

  The present inventors have intensively studied to solve the above problems. As a result, it has a repeating unit obtained by polycondensation of a specific tetracarboxylic acid or its acid anhydride and a specific aromatic diamine, and a specific actinic functional group was introduced at both ends thereof. The photosensitive polyimide precursor represented by the formula (3) or (5) described later has a low coefficient of thermal expansion and residual stress, does not form a poorly soluble layer during development, and adheres to a copper substrate, copper wiring, or the like. It has been found that a polyimide resin film having excellent properties and high breaking strength and elongation at break can be formed, and that when the film is formed on the silicon wafer, the warpage generated on the silicon wafer is small. Furthermore, this photosensitive polyimide precursor, and the photosensitive resin composition containing a thiophenecarboxylic acid ester derivative represented by the formula (7) described later as a photosensitive auxiliary agent are excellent in compatibility and are in close contact with copper. The present inventors have found that a polyimide resin film having extremely excellent properties can be formed and generalized these findings to complete the present invention.

Thus, according to the first aspect of the present invention, the following photosensitive polyimide precursors (1) to (3) are provided.
(1) In the main chain, the formula (a)

(Wherein R ¹ represents a tetravalent organic group) and a tetracarboxylic acid represented by the formula (b)

(Wherein R ² represents a divalent organic group having an aromatic group) and obtained by polycondensation with an aromatic diamine represented by formula (1)

(Wherein R ¹ and R ² represent the same meaning as described above.)
Having a repeating unit represented by
A photosensitive polyimide precursor having actinic functional groups introduced at both ends thereof,
The tetracarboxylic acid represented by the formula (a) or its acid anhydride is an aromatic tetracarboxylic acid having a rigid structure or its acid anhydride with respect to the total number of moles of the tetracarboxylic acid or its acid anhydride. ~ 100 mol% is contained,
The aromatic diamine represented by the formula (b) is represented by the formula (2)

(Wherein r ¹ , r ² , r ³ , r ⁴ , r ⁵ , r ⁶ , r ⁷ , r ⁸ , r ⁹ , and r ¹⁰ are each independently a hydrogen atom, a halogen atom, or C 1-6. A thiophene-containing aromatic diamine represented by an alkyl group, a C1-6 alkoxy group, or a phenyl group which may have a substituent, and an aromatic diamine having a rigid structure (formula (2) A thiophene-containing aromatic diamine represented by the formula (1) and (a rigid aromatic diamine) in a molar ratio of 3:97 to 50:50, and
Said actinic radiation functional group is of formula (c)

(Wherein A ¹ represents a photopolymerizable carbon-carbon double bond group) or a formula (d)

(Wherein, A ² is photopolymerizable carbon - represents a group having a carbon double bond.) Photosensitive polyimide precursor, which is a group represented by the.
(2) Formula (3)

[Wherein R ¹ and R ² represent the same meaning as described above. Z ¹ represents the formula (4)

(In the formula, R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ each independently represents a substituent having a photopolymerizable carbon-carbon double bond, and X represents —C (= O) —O—, —O—, —C (═O) —CH ₂ —O—, —O—C (═O) —O—, —SO ₂ —, —SO ₃ —, or a single bond is represented. , J is 0 or 1, and k is an integer of 1 to 3. When k is 2 or 3, the formula (e)

The groups represented by may be the same or different. ), And i represents an integer of 5 to 10,000. ] The photosensitive polyimide precursor as described in (1) represented by these.
(3) Formula (5)

[Wherein R ¹ and R ² represent the same meaning as described above. Z ² represents the formula (6)

(Wherein R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² each independently represents a substituent having a photopolymerizable carbon-carbon double bond, and q is 0 or 1) .) Represents an actinic functional group represented by p), and p represents an integer of 5 to 10,000. ] The photosensitive polyimide precursor as described in (1) which is a compound represented by this.

According to the second aspect of the present invention, the following photosensitive resin compositions (4) and (5) are provided.
(4) (A) The photosensitive polyimide precursor described in (1), (B) a photoauxiliary agent having a photopolymerizable functional group, (C) 1H-tetrazole derivative, (D) a photopolymerization initiator, and ( E) A photosensitive resin composition containing a solvent.
(5) (B) Photosensitive auxiliary having a photopolymerizable functional group is represented by the formula (7)

(In the formula, each of s and t independently represents an integer of 2 to 16, R ¹³ and R ¹⁴ each independently represents a hydrogen atom, a carboxyl group, —CONH ₂ or a cyano group, R ¹⁵ , R ¹⁶ each independently represents a hydrogen atom or a C1-5 alkyl group.) The photosensitive resin composition according to (4), which contains a thiophenecarboxylic acid ester derivative represented by:

By using the photosensitive polyimide precursor of the present invention, it is possible to form a polyimide resin film having a small coefficient of thermal expansion and residual stress, excellent adhesion to a copper substrate or copper wiring, and a large breaking strength and breaking elongation. it can.
Further, when a film is formed on a silicon wafer by using the photosensitive polyimide precursor of the present invention, even when the film is formed only on one side of the silicon wafer, the warp generated on the silicon wafer is small.
By using the photosensitive resin composition of the present invention, the coefficient of thermal expansion and residual stress are small, a hardly soluble layer is not formed at the time of development, excellent adhesion to a copper substrate or copper wiring, etc., breaking strength and breaking elongation A large polyimide resin film can be formed.

  Hereinafter, the present invention will be described in detail by dividing it into 1) a photosensitive polyimide precursor and 2) a photosensitive resin composition.

1) Photosensitive polyimide precursor The photosensitive polyimide precursor of the present invention comprises:
(Α) obtained by polycondensing the tetracarboxylic acid represented by the formula (a) or an acid anhydride thereof and the aromatic diamine represented by the formula (b) in the main chain, A photosensitive polyimide precursor having a repeating unit represented by formula (1) and having an actinic functional group introduced at both ends thereof,
(Β) The tetracarboxylic acid or acid anhydride thereof contains a rigid structure aromatic tetracarboxylic acid or acid anhydride thereof in an amount of 50 to 100 mol% based on the total number of moles of the tetracarboxylic acid or acid anhydride. Is,
(Γ) The aromatic diamine is a thiophene-containing aromatic diamine represented by the formula (2) and an aromatic diamine having a rigid structure (thiophene-containing aromatic diamine represented by the formula (2)); (Rigid structure aromatic diamine) in a molar ratio of 3:97 to 50:50, and
(Δ) The actinic radiation functional group is a group represented by the formula (c) or a group represented by the formula (d).

(Α) Repeating Unit Represented by Formula (1) The photosensitive polyimide precursor of the present invention contains, in the main chain, a tetracarboxylic acid represented by the formula (a) or an acid anhydride thereof (hereinafter referred to as “ Tetracarboxylic acid or the like (sometimes referred to as (a) ") and the aromatic diamine represented by the formula (b) (hereinafter also referred to as" aromatic diamine (b) ") are polycondensed. It has a repeating unit represented by the above formula (1).

(A) Tetracarboxylic acid etc. In the present invention, tetracarboxylic acid etc. (a) is a compound (or compound group) represented by the above formula (a), and has a rigid structure aromatic tetracarboxylic acid or acid anhydride thereof. Product (hereinafter sometimes referred to as “rigid structure aromatic tetracarboxylic acid etc.”) with respect to the total number of moles of tetracarboxylic acid etc. (a), 50 to 100 mol%, preferably 80 to 100 mol%, More preferably, it contains 85 to 100 mol%. In this specification, tetracarboxylic acid or its acid anhydride may be collectively referred to as “tetracarboxylic acid or the like”.
In the present specification, the “rigid structure” means a structure composed of a rod-like rigid straight chain that has low mobility and is not easily bent by itself. A rigid aromatic tetracarboxylic acid or acid anhydride thereof is (x) a tetracarboxylic acid or acid anhydride having an aromatic ring composed of a single ring or a condensed ring, and (y) the fragrance of (x) above. A tetracarboxylic acid having a structure in which a group ring is bonded by a single bond or an acid anhydride thereof. Examples of (x) include pyromellitic acid, pyromellitic dianhydride, naphthalenetetracarboxylic acid and naphthalenetetracarboxylic dianhydride, and examples of (y) include biphenyltetracarboxylic acid and biphenyltetracarboxylic acid. A dianhydride is mentioned. When the content ratio of the aromatic tetracarboxylic acid having a rigid structure in the tetracarboxylic acid etc. (a) is smaller than 50 mol%, the breaking strength and breaking elongation of the formed polyimide resin film are also lowered. In addition, the coefficient of thermal expansion and residual stress increase, and it becomes difficult to suppress warpage of the silicon wafer.

Examples of the tetracarboxylic acid (a) include the following compounds.
Examples of the rigid aromatic tetracarboxylic acid include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, benzene-1,2,3,4-tetra Carboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, naphthalene-2,3,6 7-tetracarboxylic dianhydride, naphthalene-1,2,5,6-tetracarboxylic dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,2,5 , 8-tetracarboxylic dianhydride, naphthalene-1,2,6,7-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1 , 2,5,6-tetracarboxylic Dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1, 4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4 , 5,8-tetracarboxylic dianhydride, 1,4,5,8-tetrachloronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl Tetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-diphenyltetracarboxylic dianhydride, 2,3 ″, 4 4 "-p-terphenyltetracarboxylic dianhydride, 2,2", 3,3 "- -Terphenyltetracarboxylic dianhydride, 2,3,3 ", 4" -p-terphenyltetracarboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -propane dianhydride 2,2-bis (3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride Bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride, bis (3 4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride Perylene-2,3,8,9-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, perylene-4,5,10,11-tetracarboxylic dianhydride Anhydride, perylene-5,6,11,12-tetracarboxylic dianhydride, phenanthrene-1,2,7,8-tetracarboxylic dianhydride, phenanthrene-1,2,6,7-tetracarboxylic acid Aromatic tetracarboxylic dianhydrides such as dianhydrides and phenanthrene-1,2,9,10-tetracarboxylic dianhydrides and their water additions; cyclopentane-1,2,3,4-tetracarboxylic acids Dianhydride, cyclobutanetetracarboxylic dianhydride, bicyclo [2,2,2] oct-7-ene-2-exo, 3-exo, 5-exo, 6-exotetracarboxylic acid 2,3: 5 6-2 Alicyclic acid dianhydrides such as bicyclo [2,2,1] heptane-2-exo, 3-exo, 5-exo, 6-exotetracarboxylic acid 2,3: 5,6-dianhydride Pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride Heterocyclic derivative acid dianhydrides such as tetracarboxylic acids corresponding to these.

  Among these, since a coefficient of thermal expansion and residual stress is small and a film having excellent adhesion to a copper substrate or the like can be obtained more easily, in the present invention, as a rigid structure aromatic tetracarboxylic acid, etc. It is preferable to use at least one selected from the group consisting of acid, pyromellitic dianhydride (PMDA), biphenyltetracarboxylic acid, and biphenyltetracarboxylic dianhydride (s-BPDA).

  The tetracarboxylic acid or the like (a) used in the present invention may contain a flexible tetracarboxylic acid or the like (flexible structure tetracarboxylic acid or the like) in addition to the rigid aromatic tetracarboxylic acid or the like. Examples of the tetracarboxylic acid having a flexible structure include an aromatic tetracarboxylic acid having a structure in which two or more aromatic rings are bonded by a carbonyl group (> C═O) or an oxygen atom (—O—). Of these, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) is preferably used.

(B) Aromatic diamine The aromatic diamine (b) used in the present invention is a thiophene-containing aromatic diamine represented by the formula (2) (hereinafter sometimes referred to as “aromatic diamine (2)”). The aromatic diamine having a rigid structure in a molar ratio of (aromatic diamine (2)) and (aromatic diamine having a rigid structure) is 3:97 to 50:50, preferably 3:97 to 30:70. It contains in the ratio.
In the formula (b), examples of the “divalent organic group” as R ² include a thiophene-containing aromatic diamine represented by the formula (2) and a rigid structure aromatic diamine. A rigid structure part is mentioned. The “rigid structure” in the aromatic diamine having a rigid structure refers to a structure having a rod-like rigid straight chain. A rigid aromatic diamine is distinguished from a flexible aromatic diamine having a single bond such as an ether bond or a methylene (—CH ₂ —) group in the main chain in that it has a rigid structure.

  By using the aromatic diamine (2) in the above proportion as the aromatic diamine (b), the thermal expansion coefficient and residual stress, which are the objects of the present invention, are small, excellent in adhesion to a copper substrate, etc., and fractured. A film capable of suppressing warpage of the silicon wafer can be easily obtained without reducing the strength and elongation at break.

In the formula (2), r ^{1 to} r ¹⁰ each independently represent a hydrogen atom, a halogen atom, a C 1-6 alkyl group, a C 1-6 alkoxy group, or an optionally substituted phenyl group. To express. As this substituent, a halogen atom, a C1-6 alkyl group, etc. are mentioned, for example.

Examples of the halogen atom for r ^{1 to} r ¹⁰ include a fluorine atom, a chlorine atom, and a bromine atom. As C1-6 alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, n-pentyl group, isopentyl group, neopentyl group , N-hexyl group and the like. Examples of the C1-6 alkoxy group include methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, t-butoxy group, pentyloxy group, hexyloxy group and the like. Examples of the phenyl group that may have a substituent include a phenyl group, a 4-chlorophenyl group, and a 4-methylphenyl group.
Among these, all of r ^{1 to} r ¹⁰ are preferably hydrogen atoms.
The aromatic diamine (2) can be produced, for example, by the method shown below.

(Wherein, r ^{1 to} r ¹⁰ represent the same meaning as described above, and X represents a halogen atom such as a bromine atom.)
That is, 4-nitrophenacyl halide represented by formula (f) and sodium sulfide (which may be a hydrate) are reacted in the presence of a base, and represented by formula (g). After obtaining the diketosulfide derivative, further reacting this with a glyoxal represented by the formula (h) to obtain a nitrobenzoylthiophene derivative represented by the formula (i), and reducing this The target product can be obtained.
In any reaction, the reaction proceeds smoothly in a temperature range from 0 ° C. to the boiling point of the solvent used.
After completion of the reaction, the target product can be isolated according to a conventional method.

  Examples of the rigid aromatic diamine used in the present invention include 4,4′-diaminobenzanilide, 4,4′-diamino-2,2′-ditrifluoromethylbiphenyl, and 2,2′-di (p- Aminophenyl) -5,5′-bisbenzoxazole, 2,2′-di (p-aminophenyl) -6,6′-bisbenzoxazole, 2,2′-di (p-aminophenyl) -5, 5'-bisbenzimidazole, 3,6- (4-aminophenyl) pyridazine, 4,4'-diaminobenzanilide, p-phenylenediamine (PPDA), 4,4'-diaminobiphenyl, m-phenylenediamine, 1 -Isopropyl-2,4-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl Rufide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 1,4-bis (4-aminophenoxy) benzene, benzidine 4,4 ″ -diamino-p-terphenyl, 3,3 ″ -diamino-p-terphenyl, bis (p-aminocyclohexyl) methene, bis (p-β-amino-t-butylphenyl) ether, bis (P-β-methyl-δ-aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl-5-aminopentyl) benzene, 1,5- Diaminonaphthalene, 2,6-diaminonaphthalene, 2,4-bis (β-amino-t-butyl) toluene, 2,4-diamidine Examples include toluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylenediamine, and p-xylylenediamine.

  Among these, 2,2′-di (p-aminophenyl) -5,5′-bisbenzoxazole (abbreviation = NPN), 2,2′-di (p-aminophenyl) -6,6′-bis Benzoxazole (abbreviation = OPO), 2,2′-di (p-aminophenyl) -5,5′-bisbenzimidazole, 3,6- (4-aminophenyl) pyridazine (abbreviation = DAPPZ), 4,4 '-Diaminobenzanilide (abbreviation = DABA) is preferred. These chemical formulas are shown below in order.

In the present invention, in addition to the aromatic diamine, a diamine having a flexible structure may be used in order to improve the flexibility of the formed polyimide film and the adhesion to a metal or a substrate.
Here, the flexible structure means that it is not the rigid structure.
When using a flexible structure diamine, the ratio of the flexible structure diamine with respect to the whole aromatic diamine (b) is usually 30 mol% or less, preferably 20 mol%.

  As the flexible structure diamine, the bonding position of the substituent bonded to the heterocyclic ring of the main chain such as aromatic diamine (2) (for example, 2,5-bis (4-aminobenzoyl) thiophene) is ortho-position or meta-position. A diamine containing an ether structure in the main chain such as oxydianiline; and a siloxane structure in the main chain such as 1,3-diaminopropyl-1,1,3,3-tetramethyldisiloxane Examples include diamines. Specific examples of the flexible structure diamine include 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 4,4'-diaminodiphenylethane, 3,3'-diaminodiphenylethane, 4,4'- Examples thereof include diaminodiphenylmethane and 3,3′-diaminodiphenylmethane.

The photosensitive polyimide precursor of the present invention is represented by the formula (1) obtained by polycondensation of the tetracarboxylic acid or the like (a) and the aromatic diamine (b) in the main chain. It has a repeating unit and has an actinic functional group introduced at both ends thereof.
The actinic functional group is a group represented by the formula (c) or a group represented by the formula (d). In the formulas (c) and (d), A ¹ and A ² each independently represents a group having a photopolymerizable carbon-carbon double bond.
Among them, as the photosensitive polyimide precursor of the present invention, the formula (3)

Or a compound represented by the formula (5)

It is preferable that it is a compound represented by these.
In formulas (3) and (5), R ¹ and R ² represent the same meaning as described above, and i and p represent an integer of 5 to 10,000. i and p are preferably 20 to 500, more preferably 30 to 300, from the balance of resin strength (membrane mechanical properties) and ease of varnish handling (varnish viscosity).
Z ¹ represents the formula (4)

The actinic radiation functional group represented by these is shown.
In formula (4), R ^{3 to} R ⁷ each independently represent a substituent having a photopolymerizable carbon-carbon double bond.

  Examples of the substituent having a photopolymerizable carbon-carbon double bond include an acryloyloxymethylene group; a methacryloyloxymethylene group; an optionally substituted vinyl group, propenyl group, isopropenyl group, butenyl group, C2-6 alkenyl groups such as a pentynyl group, a hexynyl group, and a 2-ethylbutenyl group; Examples of the substituent for the C2-6 alkenyl group include halogen atoms such as fluorine atom, chlorine atom and bromine atom; phenyl group; methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl. C1-4 alkyl groups such as a group; C1-4 alkoxy groups such as a methoxy group, an ethoxy group, and an n-propoxy group; and the like.

X is —C (═O) —O—, —O—, —C (═O) —CH ₂ —O—, —O—C (═O) —O—, —SO ₂ —, —SO _3. -Represents a single bond or -C (= O) -O-.
j is 0 or 1, and k is an integer of 1 to 3. When k is 2 or 3, the following formula

The groups represented by may be the same or different. Further, the substitution (bonding) position of the group may be any of o-, m-, and p-positions with respect to the amino group.
Z ² represents the formula (6)

The actinic radiation functional group represented by these is shown.
In the formula, R ^{8 to} R ¹² each independently represent a substituent having a photopolymerizable carbon-carbon double bond similar to R ^{3 to} R ^7, and q is 0 or 1. Also, the following formula

The substitution (bonding) position of the group represented by is not particularly limited.

  The photosensitive polyimide precursor of the present invention can be synthesized by polycondensing the tetracarboxylic acid or the like (a) and the aromatic diamine (b) in a polar organic solvent by a conventional method. Each monomer [the tetracarboxylic acid and the like (a) and the aromatic diamine (b)] is used in an approximately equimolar ratio. Furthermore, in order to introduce actinic functional groups at both ends, usually, at the time of polycondensation of these monomer components, it has a photopolymerizable carbon-carbon double bond, and tetracarboxylic acid or the like (a), or A compound having reactivity with the aromatic diamine (b) is present.

The compound represented by the formula (3) having the actinic functional group Z ¹ at both ends is obtained by adding, for example, tetracarboxylic acid or the like (a) to a mixture of an aromatic diamine (b) and aminobenzenes described later. It can be obtained by a polycondensation reaction by a conventional method. According to this method, the polymer compound represented by the high molecular weight formula (3) can be obtained stably.

  More specifically, (i) tetracarboxylic acid or the like (a) 1 mol of aromatic diamine (b) is usually 0.850 to 0.990 mol, preferably 0.900 to 0.970 mol. (Ii) Aminobenzene is usually used in an amount of 0.400 to 0.020 mol, preferably 0.110 to 0.040 mol, more preferably 0.000 mol per 1 mol of aromatic diamine (b). It is used in a proportion of 100 to 0.050 mol, and (iii) tetracarboxylic acid or the like (a) 1 mol of aromatic diamine (b) and aminobenzenes in a total amount, usually 1.100. To 0.900 mol, preferably 1.100 to 0.950 mol, more preferably 1.060 to 0.990 mol.

In the polycondensation reaction, each component may be reacted in a polar organic solvent such as dimethylacetamide according to a conventional method for synthesizing polyimide.
The reaction temperature is usually in the range of −20 ° C. to + 80 ° C., and the reaction time is in the range of 0.5 to 80 hours.

  When the solubility of the monomer in the reaction system is low, the temperature can be raised to a temperature at which the monomer can be dissolved, and a preliminary reaction can be performed until the oligomer becomes soluble in the reaction system. However, the photosensitive polyimide precursor of the present invention is not limited to a specific synthesis method.

  Examples of aminobenzenes to be used include compounds represented by the following formula (4-1).

(Wherein R ^{3 to} R ⁷ , X, j and k represent the same meaning as described above).
Specific examples of the compound represented by the formula (4-1) include o-aminobenzoic acid [tris (methacryloyl) pentaerythritol] ester, o-aminobenzoic acid [tris (acryloyl) pentaerythritol] ester, m-amino. Benzoic acid [tris (methacryloyl) pentaerythritol] ester, m-aminobenzoic acid [tris (acryloyl) pentaerythritol] ester, p-aminobenzoic acid [tris (methacryloyl) pentaerythritol] ester, p-aminobenzoic acid [tris ( Acryloyl) pentaerythritol] ester, 5-amino-isophthalic acid [tris (methacryloyl) pentaerythritol] diester, 5-amino-isophthalic acid [tris (acryloyl) pentaerythritol] diester, o- Minobenzoic acid [pentakis (methacryloyl) dipentaerythritol] ester, o-aminobenzoic acid [pentakis (acryloyl) dipentaerythritol] ester, m-aminobenzoic acid [pentakis (methacryloyl) dipentaerythritol] ester, m-aminobenzoic acid Examples include acid [pentakis (acryloyl) dipentaerythritol] ester, p-aminobenzoic acid [pentakis (methacryloyl) dipentaerythritol] ester, p-aminobenzoic acid [pentakis (acryloyl) dipentaerythritol] ester, and the like. Among these, p-aminobenzoic acid [tris (methacryloyl) pentaerythritol] ester is particularly preferable because of its excellent economic efficiency, operability, high sensitivity, high resolution, and the like.
Such aminobenzenes such as aminobenzenecarboxylic acid esters can be produced according to the method described in JP-A-8-82931.

The compound represented by the formula (5) having the actinic functional group Z ² at both ends is, for example, trimellitic such as aromatic diamine (b), trimellitic acid anhydride [tris (methacryloyl) pentaerythritol] ester, etc. It can be obtained by adding an acid derivative and tetracarboxylic acid (a) and performing a condensation reaction by a conventional method.
In addition, the compound represented by the formula (5) is obtained by subjecting a polymer obtained by condensation reaction of a tetracarboxylic acid or the like (a) and an aromatic diamine (b) to a terminal such as aminobenzenesulfonic acid. It can also be produced by adding a denaturant and reacting it later. According to these methods, the polymer compound represented by the high molecular weight formula (5) can be obtained stably.

  Examples of trimellitic acid derivatives used include compounds represented by the following formula (6-1).

(In formula, R < ⁸ > -R < ¹² > and q represent the same meaning as the above.)
Among these, the following formula (6-2)

(Wherein, R represents a hydrogen atom; or a C1-5 alkyl group such as a methyl group, an ethyl group, or an n-propyl group) is preferable, and trimellitic acid anhydride [tris (acryloyl)] Pentaerythritol] ester [in the above formula (6-2), when R = H], trimellitic acid anhydride [tris (methacryloyl) pentaerythritol] ester [in the above formula (6-2), R = methyl group The case] is particularly preferred in view of economy, operability, high sensitivity, high resolution, and the like.

  Such trimellitic acid derivatives can be synthesized according to the method described in JP-A-8-95247.

A compound in which the actinic functional group Z ² represented by the formula (6) is introduced into both ends is condensed by an ordinary method by adding a trimellitic acid derivative and tetracarboxylic acid (a) to the aromatic diamine (b). It can be obtained by reacting or adding a tetracarboxylic acid or the like (a) to a mixture of the aromatic diamine (b) and trimellitic acid derivative and subjecting it to a condensation reaction by a conventional method.

  More specifically, (i) tetracarboxylic acid or the like (a) is usually 0.850-0.990 mol, preferably 0.900-0.970 mol, per 1 mol of aromatic diamine (b). (Ii) tetracarboxylic acid or the like (a) 1 mol of trimellitic acid derivative is usually 0.400 to 0.020 mol, preferably 0.110 to 0.040 mol, more preferably 0 In addition, it is used at a ratio of 100 to 0.050 mol, and (iii) tetracarboxylic acid or the like (b) and trimellitic acid derivative in a total amount with respect to 1 mol of aromatic diamine (b), usually 1 .100 to 0.900 mol, preferably 1.100 to 0.990 mol, more preferably 1.060 to 1.020 mol.

In the polycondensation reaction, each component may be reacted in a polar organic solvent such as dimethylacetamide according to a conventional method for synthesizing polyimide. The reaction temperature is usually in the range of −20 ° C. to + 80 ° C., and the reaction time is in the range of 0.5 to 80 hours.
When the solubility of the monomer in the reaction system is low, the temperature can be raised to a temperature at which the monomer can be dissolved, and a preliminary reaction can be performed until the oligomer becomes soluble in the reaction system. However, the photosensitive polyimide precursor of the present invention is not limited to a specific synthesis method.

  The thermal expansion coefficient of the polyimide resin film formed using the photosensitive polyimide precursor of the present invention is usually 2.0 to 24 ppm / ° C., preferably 2.5 to 17 ppm / ° C. Therefore, there is no possibility of generation of cracks, disconnection of wiring, warping of the substrate, etc. due to heating or heat generation during manufacture or use. The coefficient of thermal expansion can be measured by the method described in <Measurement of coefficient of thermal expansion> described later.

  The polyimide resin film formed using the photosensitive polyimide precursor of the present invention is excellent in adhesiveness with a copper substrate, copper wiring or the like. The excellent adhesion can be achieved, for example, by preparing a polyimide resin film on a copper substrate obtained by forming a copper film on a silicon wafer by a sputtering process, and performing a pressure cooker test (121 ° C., 2.1 atm., 90 It can be confirmed from the absence of peeling by performing a cross-cut peeling test after 100 ° C. for 100 hours.

2) Photosensitive resin composition The photosensitive resin composition of the present invention comprises (A) a photosensitive polyimide precursor of the present invention, (B) a photosensitive auxiliary having a photopolymerizable functional group, and (C) a 1H-tetrazole derivative. , (D) a photopolymerization initiator, and (E) a solvent.

  The photosensitive resin composition of the present invention contains the photosensitive polyimide precursor of the present invention. Therefore, by using this, it is possible to form a polyimide resin film having a small coefficient of thermal expansion and residual stress, excellent adhesion to a copper substrate, copper wiring, and the like, and a large breaking strength and breaking elongation. Further, when a film is formed on the silicon wafer, a film with a small warpage generated on the silicon wafer can be formed.

(B) Photosensitive auxiliary The photosensitive auxiliary used in the photosensitive resin composition of the present invention has a photopolymerizable functional group and is generally used as a photocurable monomer.
For example, those described in Japanese Patent Application Laid-Open No. 2004-285129 and the formula (7)

The thiophenecarboxylic acid ester derivative etc. which are represented by these are mentioned.
In the present invention, it is particularly preferable to use the thiophenecarboxylic acid ester derivative represented by the formula (7) from the viewpoint of forming a film that is superior in adhesion to copper.

In formula (7), s and t each independently represent an integer of 2 to 16, R ¹³ and R ¹⁴ each independently represent a hydrogen atom, a carboxyl group, —CONH ₂ or a cyano group,
R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom; or a C1-5 alkyl group such as a methyl group or an ethyl group.

  Although the usage-amount of a photosensitive adjuvant is not specifically limited as long as it is compatible with the (A) photosensitive polyimide precursor of this invention to be used, Usually, 10-50 weight part with respect to 100 weight part of photosensitive polyimide precursor, Preferably Is 15 to 40 parts by weight, more preferably 20 to 35 parts by weight, and particularly preferably 23 to 28 parts by weight. When the amount of the photosensitive aid used is too large, it is difficult to disassemble and remove the photosensitive polyimide precursor when it is converted into a polyimide by heat treatment, and the residual stress of the film becomes high, and the semiconductor element substrate is deformed such as warpage. May be more likely to occur.

(C) 1H-tetrazole derivative In addition to (A) the photosensitive polyimide precursor of the present invention, and (B) a photosensitive assistant having a photopolymerizable functional group, the photosensitive resin composition of the present invention further includes ( C) Contains a 1H-tetrazole derivative.
By adding the 1H-tetrazole derivative, it is possible to prevent the corrosiveness to copper and copper alloy, and to improve the adhesion of the formed polyimide resin film to the substrate and prevent the remaining film of the photosensitive film. .

  Examples of 1H-tetrazole derivatives include: 1H-tetrazole; 5-substituted-1H-tetrazole such as 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole; 1-methyl-1H-tetrazole 1-substituted-1H-tetrazole such as 1-phenyl-5-mercapto-1H-tetrazole and the like. Among these, 1H-tetrazole and 5-substituted-1H-tetrazole are preferable.

  The amount of 1H-tetrazole derivative used is usually 0.05 to 20 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 100 parts by weight (based on solid content) of (A) photosensitive polyimide precursor. Is 0.3 to 3 parts by weight. If the amount used is too small, the effect of addition cannot be obtained. Conversely, if the amount used is too large, the effect tends to be saturated.

(D) Photopolymerization initiator In the photosensitive resin composition of the present invention, (A) the photosensitive polyimide precursor of the present invention, (B) a photosensitive auxiliary agent having a photopolymerizable functional group, and (C) 1H— In addition to the tetrazole derivative, it further contains (D) a photopolymerization initiator.
A conventionally well-known photoinitiator can be used as a photoinitiator. Specifically, those described in JP-A No. 2004-285129, 3,3′-bismethoxycarbonyl-4,4′-bis-t-butylperoxycarbonyl) benzophenone, 3,4′-bismethoxycarbonyl -4,3'-bis-t-butylperoxycarbonyl) benzophenone, 4,4'-bismethoxycarbonyl-3,3'-bis-t-butylperoxycarbonyl) benzophenone, and the like.
A photoinitiator can be used individually by 1 type or in combination of 2 or more types.

  Although the usage-amount of a photoinitiator is not specifically limited, It is 0.01-10 weight part normally with respect to 100 weight part of (A) photosensitive polyimide precursors of this invention, Preferably it is 0.1-5 weight part. More preferably, it is 1 to 5 parts by weight.

(E) Solvent As the solvent used in the photosensitive resin composition of the present invention, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, tetramethylurea, hexamethylphosphoric triamide, etc. Imides; sulfur-containing solvents such as dimethyl sulfoxide and sulfolane; lactones such as γ-butyrolaclone; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone; methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate Esters such as diethyl malonate; ethers such as diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran; dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane Chlorobenzene, o- halogenated hydrocarbons dichlorobenzene and the like; hexane, heptane, octane, benzene, toluene, hydrocarbons such as xylene; and the like.
These solvents can be used alone or in combination of two or more.
Especially, since it is excellent in solubility, a polar solvent is preferable and N-methyl-2-pyrrolidone, N, N-dimethylformamide, and N, N-dimethylacetamide are more preferable.

  The amount of solvent used is sufficient to dissolve each component uniformly. Specifically, although it varies depending on the type of component to be used, the weight ratio is usually 3 to 25 times, preferably 5 to 20 times, and more preferably 6 to the amount of (A) the photosensitive polyimide precursor. 10 times the amount.

  The photosensitive resin composition of the present invention may contain other components as desired within a range not impairing the intended effect of the present invention. Examples of other components include an adhesion aid, a leveling agent, and a polymerization inhibitor.

  The photosensitive resin composition of the present invention comprises (A) the photosensitive polyimide precursor of the present invention, (B) a photoauxiliary agent having a photopolymerizable functional group, (C) 1H-tetrazole derivative, and (D) photopolymerization. It can be prepared by mixing and kneading the initiator, the solvent (E), and, if necessary, other components by a conventionally known method.

The photosensitive resin composition of the present invention (hereinafter sometimes referred to as “the composition of the present invention”) can be used as follows.
First, the composition of the present invention is applied to a suitable support surface such as a silicon wafer, a ceramic substrate, or an aluminum substrate.
Examples of the coating method include spin coating using a spinner, spray coating using a spray coater, dipping, printing, roll coating, and the like. Although there is no restriction | limiting in particular about an application quantity, After application | coating, the exposure film thickness after prebaking at 60-100 degreeC for 1 to 60 minutes and drying a coating film is 1-50 micrometers normally, Preferably it is 2-20 micrometers, More preferably It is preferable to adjust so that it may become 3-15 micrometers. Subsequently, actinic radiation is irradiated to a desired pattern shape. As the actinic radiation, X-rays, electron beams, ultraviolet rays, visible rays and the like can be used, but those having a wavelength in the range of 200 to 500 nm are preferable.

  Next, a relief pattern is obtained by dissolving and removing the unirradiated portion with a developer. Examples of the developer include amide solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide; cyclic ketone solvents such as cyclopentanone and cyclohexanone; methanol, isopropyl alcohol, and the like. Alcohol solvents; water; mixed solvents thereof; and the like. As a developing method, various methods such as spraying, paddle, dipping, and ultrasonic can be employed.

  Next, the relief pattern formed by development is rinsed. Examples of the rinsing liquid include alcohols such as methanol, ethanol and isopropyl alcohol; esters such as butyl acetate; Next, heat treatment is performed to form an imide ring, and the polyamic acid compound is converted to a polyimide to obtain an insulating film having high heat resistance.

  The photosensitive resin composition according to the present invention can be used not only for applications related to semiconductor elements but also as an interlayer insulating film for multilayer circuits, a cover coat for flexible copper-clad plates, a solder resist film, a liquid crystal alignment film, and the like.

  According to the photosensitive resin composition of the present invention, it is possible to form a low thermal expansion photosensitive polyimide resin film excellent in adhesion to a copper substrate by suppressing formation of a surface hardly soluble layer during exposure and development. Further, even when a multilayer circuit board is produced on a silicon wafer and the silicon wafer is polished and thinned, the silicon wafer is hardly warped. The photosensitive resin composition of the present invention is suitable for production of a thin-film multilayer circuit board or a thinned power semiconductor substrate.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to these Examples.
Synthesis Example 1 Synthesis of 2,5-bis (4-aminobenzoyl) thiophene

  13 g of sodium sulfide nonahydrate dissolved in water was added dropwise to a solution of 24.4 g of 4-nitrophenacyl bromide represented by the formula (f-1) in 300 ml of acetone while stirring with ice cooling. After stirring for 1 hour, 300 ml of ice water was added to the reaction mixture, and the deposited precipitate was filtered and dried to obtain 14.6 g of a diketosulfide derivative represented by the formula (g-1).

  While stirring 7.2 g of the obtained diketosulfide derivative (g-1) and 3.5 g of a 40% aqueous solution of glyoxal represented by the formula (h-1) in a mixed solvent of 100 ml of methanol and 100 ml of dichloromethane, Then, 4 ml of 28% sodium methoxide was added dropwise and stirred at 40 ° C. for 6 hours. The precipitate deposited from the reaction solution was collected by filtration to obtain 6.1 g of a nitrobenzoylthiophene derivative represented by the formula (i-1). 3.8 g of the obtained nitrobenzoylthiophene derivative (i-1) was dissolved in 50 ml of acetic acid, and with stirring, a solution of 17.0 g of tin chloride dissolved in 30 ml of hydrochloric acid was added dropwise. Warmed and stirred for 4 hours. After allowing to cool, the reaction mixture was neutralized with an aqueous sodium hydroxide solution, and the deposited precipitate was collected by filtration. Recrystallization from ethanol gave 2.2 g of crystals.

From the melting point and NMR spectrum measurement of the obtained crystal, it was confirmed that the crystal was 2,5-bis (4-aminobenzoyl) thiophene represented by the formula (2-1).
Melting point (mp): 190-192 ° C
· ¹ H-NMR spectral data (nuclear magnetic resonance apparatus: manufactured by JEOL Ltd., using JNM.ECM Type 500M): 7.75ppm (d-d ) 4H benzene ring, 7.72ppm (s) 2H thiophene ring, 6 .79 ppm (dd) 4H benzene ring, 6.30 ppm (s) 4H amino group

Example 1
In the reactor, as aromatic diamine, 2,2′-di (p-aminophenyl) -6,6′-bisbenzoxazole 27.28 g (0.0652 mol), 2,5-bis (4-aminobenzoyl) ) 0.65 g (0.002 mol) of thiophene and 100 g of N, N-dimethylacetamide and 100 g of N-methyl-2-pyrrolidone were added as a solvent to obtain a mixed solution. To this solution, 15.26 g (0.07 mol) of pyromellitic dianhydride was added as a powder while stirring on ice. The whole volume was stirred under ice cooling for 2 hours, and then the reaction temperature was raised to 30 ° C. and reacted for 2 hours. When the reaction solution became almost uniform, the reaction solution was cooled to 10 ° C., and then 2.57 g (0.0056 mol) of p-aminobenzoic acid [tris (methacryloyl) pentaerythritol] ester was added. The mixture was reacted at 10 ° C. for 2 hours and then at 25 ° C. for 12 hours to obtain a solution containing the photosensitive polyimide precursor 1 at a resin concentration of 16% by weight. The terminal modification rate of the obtained photosensitive polyimide precursor 1 was 8%.

(Example 2)
In Example 1, the aromatic diamine was converted to 2,2′-di (p-aminophenyl) -6,6′-bisbenzoxazole 26.71 g (0.0638 mol), 2,5-bis (4-amino). A solution containing the photosensitive polyimide precursor 2 was obtained in the same manner as in Example 1 except that 1.1 g (0.0034 mol) of benzoyl) thiophene was changed.
The terminal modification rate of the photosensitive polyimide precursor 2 was 8%.

(Example 3)
In Example 1, the aromatic diamine was converted to 2,2′-di (p-aminophenyl) -6,6′-bisbenzoxazole 25.87 g (0.0618 mol), 2,5-bis (4-amino). Example 1 except that 0.866 g (0.0027 mol) of benzoyl) thiophene and 1.392 g (0.0056 mol) of 1,3-diaminopropyl-1,1,3,3-tetramethyldisiloxane In the same manner as above, a solution containing the photosensitive polyimide precursor 3 was obtained.
The terminal modification rate of the photosensitive polyimide precursor 3 was 8%.

Example 4
In Example 1, the acid anhydride was changed to 20.60 g (0.07 mol) of 3,3′-4,4′-biphenyltetracarboxylic dianhydride, and the aromatic diamine was changed to 2,2′-di ( p-aminophenyl) -6,6′-bisbenzoxazole 25.87 g (0.0618 mol) and 2,5-bis (4-aminobenzoyl) thiophene 1.74 g (0.0054 mol) In the same manner as in Example 1, a solution containing the photosensitive polyimide precursor 4 was obtained.
The terminal modification rate of the photosensitive polyimide precursor 4 was 8%.

(Example 5)
In Example 1, the acid anhydride was changed to 20.60 g (0.07 mol) of 3,3′-4,4′-biphenyltetracarboxylic dianhydride, and the aromatic diamine was changed to 2,2′-di (p -Aminophenyl) -6,6'-bisbenzoxazole except 23.02 g (0.055 mol) and 2,5-bis (4-aminobenzoyl) thiophene 3.864 g (0.012 mol) In the same manner as in Example 1, a solution containing the photosensitive polyimide precursor 5 was obtained.
The terminal modification rate of the photosensitive polyimide precursor 5 was 8%.

(Example 6)
In Example 1, the acid anhydride was changed to 20.60 g (0.07 mol) of 3,3′-4,4′-biphenyltetracarboxylic dianhydride, and the aromatic diamine was changed to 2,2′-di (p -Aminophenyl) -6,6'-bisbenzoxazole, except that it was changed to 20.25 g (0.048 mol) and 2,5-bis (4-aminobenzoyl) thiophene 6.06 g (0.0188 mol) In the same manner as in Example 1, a solution containing the photosensitive polyimide precursor 6 was obtained.
The terminal modification rate of the photosensitive polyimide precursor 6 was 8%.

(Example 7)
In Example 1, 20.3 g (0.07 mol) of 3,3′-4,4′-biphenyltetracarboxylic dianhydride was used as the acid anhydride, and 3,6- (4-aminophenyl) was used as the aromatic diamine. ) Photosensitive polyimide precursor in the same manner as in Example 1 except that 17.10 g (0.0652 mol) of pyridazine and 0.65 g (0.002 mol) of 2,5-bis (4-aminobenzoyl) thiophene were changed. A solution containing body 7 was obtained.
The terminal modification rate of the photosensitive polyimide precursor 7 was 8%.

(Example 8)
In Example 1, the aromatic diamine was changed to 14.82 g (0.0652 mol) of 4,4′-diaminobenzanilide and 0.65 g (0.002 mol) of 2,5-bis (4-aminobenzoyl) thiophene. A solution containing the photosensitive polyimide precursor 8 was obtained in the same manner as in Example 1 except that.
The terminal modification rate of the photosensitive polyimide precursor 8 was 8%.

(Comparative Example 1)
Example 1 except that the aromatic diamine was changed to only 28.12 g (0.0672 mol) of 2,2′-di (p-aminophenyl) -6,6′-bisbenzoxazole in Example 1. In the same manner as above, a solution containing the photosensitive polyimide precursor 9 was obtained.
The terminal modification rate of the photosensitive polyimide precursor 9 was 8%.

(Comparative Example 2)
In Example 1, the aromatic diamine was mixed with 2,2′-di (p-aminophenyl) -6,6′-bisbenzoxazole 27.28 g (0.0652 mol) and 1,3-diaminopropyl-1, A solution containing the photosensitive polyimide precursor 10 was obtained in the same manner as in Example 1 except that the amount was changed to 0.5 g (0.0020 mol) of 1,3,3-tetramethyldisiloxane.
The terminal modification rate of the photosensitive polyimide precursor 10 was 8%.

(Comparative Example 3)
In Example 1, the acid anhydride was changed to 3,3′-4,4′-biphenyltetracarboxylic dianhydride 20.60 g (0.07 mol), and the aromatic diamine was changed to 2,2′-di (p -Aminophenyl) -6,6'-bisbenzoxazole A solution containing the photosensitive polyimide precursor 11 was obtained in the same manner as in Example 1 except that the amount was changed to 28.12 g (0.0672 mol).
The terminal modification rate of the photosensitive polyimide precursor 11 was 8%.

  About the photosensitive polyimide precursors 1-11 obtained in Examples 1-8 and Comparative Examples 1-3, the terminal modification rate by a monomer composition and an actinic functional group is shown together in the following Table 1.

<Measurement of thermal expansion coefficient>
Each of the solutions containing the photosensitive polyimide precursors 1 to 11 obtained in Examples 1 to 8 and Comparative Examples 1 to 3 was spinnered on a 6-inch silicon wafer (thickness: 625 μm, silane coupling agent treated product). And dried in an oven at 60 ° C. for 30 minutes. Next, in an inert oven, hold at 50 ° C. for 60 minutes, raise the temperature at 5 ° C./1 minute, hold at 200 ° C. for 60 minutes, further raise the temperature at 5 ° C./1 minute, hold at 400 ° C. for 60 minutes, Thereafter, the temperature was returned to room temperature and maintained for 4 hours to prepare a polyimide resin film.

  Subsequently, the polyimide resin film was peeled and collected from the silicon substrate by 50% hydrofluoric acid treatment, sufficiently washed with water, and then vacuum dried at 130 ° C. for 3 hours to obtain a polyimide resin film for evaluation. The thermal expansion coefficient of each obtained polyimide resin film was measured with the following apparatus and conditions. The results are shown in Table 1 below.

In the table, abbreviations have the following meanings.
PMDA: pyromellitic dianhydride s-BPDA: 3,3′-4,4′-biphenyltetracarboxylic dianhydride NPN: 2,2′-di (p-aminophenyl) -6,6 '-Bisbenzoxazole DABT: 2,5-bis (4-aminobenzoyl) thiophene Si diamine: 1,3-diaminopropyl-1,1,3,3-tetramethyldisiloxane DAPPZ: 3,6- (4-aminophenyl) pyridazine, DABA: 4,4′-diaminobenzanilide, TMEA: p-aminobenzoic acid [tris (methacryloyl) pentaerythritol] ester

・ Measuring device: TMA120c type manufactured by Seiko Denshi Kogyo Co., Ltd. ・ Measuring conditions: Test piece shape = width 4 mm, length 25 mm, measurement length 10 mm,
・ Measurement format: Tensile load = 2g
Measurement temperature: 1 cycle = room temperature → 300 ° C → 20 ° C
2 cycles = 20 ° C → 200 ° C
The change in average expansion coefficient at 20 to 200 ° C. in the second cycle of temperature increase is described.
・ Temperature increase rate: 5 ° C./min ・ Measurement atmosphere: In nitrogen gas

(Examples 9 to 17 and Comparative Examples 4 to 6)
For 100 parts by weight of the photosensitive polyimide precursors 1 to 11 obtained in Examples 1 to 8 and Comparative Examples 1 to 3, triethylene glycol diacrylate: “3EG-A” and 2, 5-thiophenedicarboxylic acid di (2-acryloyloxyethyl) ester “TCDAE”, as a photopolymerization initiator, N-phenylglycine: “NPG”, and “BT-2” (organic peracid benzophenone derivative; manufactured by Chisso Corporation) ), And 1H-tetrazole in an amount (parts by weight) shown in Table 2 below, and further a solvent (dimethylacetamide (DMAc): N-methylpyrrolidone (NMP) = 1: 1 weight ratio mixed solvent). In addition, the resin concentration was adjusted to 13% by weight to obtain a uniform solution (photosensitive resin compositions 1 to 12).

  About the obtained photosensitive resin compositions 1-12, according to the method shown below, the measurement of the thermal expansion coefficient of the photosensitive evaluation, the copper substrate adhesion evaluation, the presence or absence of the pattern surface hardly soluble layer, and the photosensitive polyimide resin film was performed. It was. The results are shown in Table 2 below.

<Evaluation of photosensitive resin composition>
The photosensitive resin compositions 1 to 12 obtained in Examples 9 to 17 and Comparative Examples 4 to 6 were respectively converted into copper substrate wafers (γ-APS on a substrate obtained by forming copper on a 4-inch silicon substrate by a sputtering process). A film treated with a coupling agent) was applied with a spinner and dried in an oven at 60 ° C. for 30 minutes (film thickness after prebaking 10 μm). The resulting photosensitive polyamic acid resin film was exposed through a pattern mask with PL-A501F (manufactured by Canon Inc.) at an exposure energy of 500 mj / cm ² . Next, it is immersed in a developer (CPN: NMP: H ₂ O = 63: 30: 7 weight ratio) for 2 minutes, immersed in isopropyl alcohol for 60 seconds, rinsed, and blown with nitrogen gas to dry the resolution pattern. Thereafter, the substrate was thermally imidized in an inert oven under the same heating conditions as described above. CPN is cyclopentanone.
SEM observation of the pattern (magnification: 1000 times) confirms that the pattern of L / S = 20 μm is clearly resolved (confirmation of presence or absence of poorly soluble layer). “Yes”, and the case where there was no hardly soluble layer was evaluated as “No”.

  In addition, as a photosensitivity evaluation, ○ when there is no pattern peeling (floating), △ when there is unevenness in resolution, or slight pattern peeling (floating) is seen, insufficient resolution, or pattern peeling The case where woke up occurred was evaluated as x.

<Physical property evaluation of photosensitive polyimide resin film-Measurement of thermal expansion coefficient>
Each photosensitive resin composition was spin coated on a silicon substrate (treated with a silane coupling agent). Next, after drying at 60 ° C. for 30 minutes, the entire surface of the silicon substrate was irradiated with an exposure amount of 500 mj / cm ² , and then development, rinsing and drying were performed. This substrate was heat-treated under the thermal imidization conditions to obtain a photosensitive polyimide resin film. This film was peeled from the silicon wafer using 50% hydrofluoric acid, sufficiently washed with distilled water, and then vacuum-dried at 130 ° C. for 3 hours to obtain a photosensitive polyimide resin film. The thickness of the obtained film was about 5 μm. The thermal expansion coefficient of this film was measured (the measurement apparatus, measurement conditions, etc. are the same as above).

<Evaluation of adhesion to copper>
Photosensitive resin compositions 1 to 11 were respectively applied to copper substrates obtained by forming a copper film on a silicon wafer by a sputtering process, and polyimide resin films were produced in the same manner as described above.
The adhesion between the substrate and the polyimide resin film was evaluated by a cross-cut peel test. When the cross-cut peel test is performed immediately after film formation and after the pressure cooker test (121 ° C., 2.1 atm, 90 ° C., 100 hours) and there is no peel (0/25) ○ It was evaluated.

From Table 2, it was found that the photosensitive resin composition of the present invention can form a polyimide resin film having a practical level of photosensitive performance on a copper substrate while maintaining thermal expansion rate control and copper substrate adhesion. .
Furthermore, by blending a thiophene carboxylic acid ester derivative with the photosensitizer (Examples 9 to 16), it suppresses the formation of a poorly soluble layer, and at the same time has excellent effects such as shortening the time during development and flattening the pattern surface. The effect was seen in pattern formation (development adhesion improvement) on a copper substrate.

Claims (5)

In the main chain, the formula (a)

(Wherein R ¹ represents a tetravalent organic group) and a tetracarboxylic acid represented by the formula (b)

(Wherein R ² represents a divalent organic group having an aromatic group) and obtained by polycondensation with an aromatic diamine represented by formula (1)

(Wherein R ¹ and R ² represent the same meaning as described above.)
Having a repeating unit represented by
A photosensitive polyimide precursor having actinic functional groups introduced at both ends thereof,
The tetracarboxylic acid represented by the formula (a) or an acid anhydride thereof is an aromatic tetracarboxylic acid having a rigid structure or an acid anhydride thereof in a ratio of 70 to the total number of moles of the tetracarboxylic acid or the acid anhydride. Containing 100 mol%,
The aromatic diamine represented by the formula (b) is represented by the formula (2)

(Wherein r ¹ , r ² , r ³ , r ⁴ , r ⁵ , r ⁶ , r ⁷ , r ⁸ , r ⁹ , and r ¹⁰ are each independently a hydrogen atom, a halogen atom, or C 1-6. A thiophene-containing aromatic diamine represented by an alkyl group, a C1-6 alkoxy group, or a phenyl group which may have a substituent, and an aromatic diamine having a rigid structure (formula (2) In a molar ratio of (thiophene-containing aromatic diamine represented by formula) and (rigid structure aromatic diamine), and a ratio of 3:97 to 30:70, and
Said actinic radiation functional group is of formula (c)

(Wherein A ¹ represents a photopolymerizable carbon-carbon double bond group) or a formula (d)

(Wherein, A ² is photopolymerizable carbon - represents a group having a carbon double bond.) Photosensitive polyimide precursor, which is a group represented by the. Formula (3)

[Wherein R ¹ and R ² represent the same meaning as described above. Z ¹ represents the formula (4)

(In the formula, R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ each independently represents a substituent having a photopolymerizable carbon-carbon double bond, and X represents —C (= O) —O—, —O—, —C (═O) —CH ₂ —O—, —O—C (═O) —O—, —SO ₂ —, —SO ₃ —, or a single bond is represented. , J is 0 or 1, and k is an integer of 1 to 3. When k is 2 or 3, the formula (e)

The groups represented by may be the same or different. ), And i represents an integer of 5 to 10,000. ] The photosensitive polyimide precursor of Claim 1 represented by these. Formula (5)

[Wherein R ¹ and R ² represent the same meaning as described above. Z ² represents the formula (6)

(Wherein R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² each independently represents a substituent having a photopolymerizable carbon-carbon double bond, and q is 0 or 1) .) Represents an actinic functional group represented by p), and p represents an integer of 5 to 10,000. The photosensitive polyimide precursor according to claim 1, which is a compound represented by the formula:   (A) The photosensitive polyimide precursor according to claim 1, (B) a photoauxiliary agent having a photopolymerizable functional group, (C) 1H-tetrazole derivative, (D) a photopolymerization initiator, and (E) a solvent. Containing a photosensitive resin composition. (B) A photosensitizer having a photopolymerizable functional group is represented by the formula (7)

(In the formula, each of s and t independently represents an integer of 2 to 16, R ¹³ and R ¹⁴ each independently represents a hydrogen atom, a carboxyl group, —CONH ₂ or a cyano group, R ¹⁵ , 5. The photosensitive resin composition according to claim 4, wherein each of R ¹⁶ independently represents a hydrogen atom or a C1-5 alkyl group.