JP2007031511A - Polybenzoxazole, its positive type photosensitive resin composition and pattern-forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polybenzoxazole having excellent heat resistance and low dielectric characteristics, a polybenzoxazole precursor capable of forming a high resolving degree positive type pattern developable with an alkali aqueous solution when used as a photosensitive resin composition, a positive type photosensitive resin composition containing the same, and a pattern-forming method using the composition. <P>SOLUTION: The polybenzoxazole precursor has a specific structure having a spiroindan skeleton and a phenyldiisopropylidene skeleton (bisphenol P type). The polybenzoxazole is obtained therefrom. The photosensitive resin composition comprises the polybenzoxazole precursor and a sensitizer or the polybenzoxazole precursor, a sensitizer, and a crosslinking agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a polybenzoxazole precursor, polybenzoxazole, which can be developed in an alkaline aqueous solution, and is used for applications requiring heat resistance and fine processing, such as insulating films for printed circuit boards and semiconductor coating films. The present invention relates to a positive photosensitive resin composition and a pattern forming method using the composition. More specifically, polybenzoxazole, a precursor thereof, and a positive-type photosensitive resin containing the precursor have a high resolution pattern-forming property and become a cured film having excellent physical properties such as electrical characteristics and heat resistance. The present invention relates to a composition and a pattern forming method using the composition.

  Polyimides and polybenzoxazoles have excellent properties such as high heat resistance, mechanical properties, chemical resistance, and electrical insulation, so semiconductor surface protective films, interlayer insulating films for multilayer wiring boards, and flexible wiring board cover coats Expansion to the electric and electronic fields such as membranes is expected. In particular, photosensitive polyimide and photosensitive polybenzoxazole having the function of a photoresist are materials that are attracting attention because they can greatly shorten the processing steps. In recent years, there has been a demand for higher speed and larger capacity of computers and measuring instruments in communication information processing technology. The signal propagation speed of printed wiring boards used for this has increased, and the dielectric constant has been reduced. Requests are also increasing. Further, in consideration of safety during work and influence on the environment, there is an increasing demand for a positive photosensitive resin composition that can be developed with an alkaline aqueous solution.

There have been many reports of positive photosensitive polyimides so far, but no one that can satisfy users has been made at present. This is due to inferior moisture resistance derived from the polyimide structure and problems due to moisture absorption. Polyamic acid is
1) Alkali solubility is too high due to the carboxyl group, resulting in severe film loss during development. 2) When phenolic hydroxyl groups are introduced, they remain in the final cured product, resulting in reduced moisture resistance and improved semiconductor reliability. There is a problem that it cannot be obtained.

  Therefore, recently, photosensitive polybenzoxazole precursors have attracted attention (for example, Patent Documents 1 and 2). Since polybenzoxazole has a characteristic that it has a phenolic hydroxyl group during alkali development and disappears after curing (excellent moisture resistance), development as a photosensitive polybenzoxazole attracts attention.

However, in recent years, the required level of electrical characteristics is very high, and the polybenzoxazole resins reported so far have not reached the required level because the dielectric constant is 3.0 or more. Therefore, with the aim of improving dielectric properties, polybenzoxazole containing fluorine atoms has been developed (for example, Patent Document 3), but the glass transition temperature, which is an index of heat resistance, is low, and is expensive. There was a problem.
Japanese Unexamined Patent Publication No. 27140 Japanese Patent Laid-Open No. 11451 Japanese Patent Laid-Open No. 237736

  An object of the present invention is to provide a polybenzoxazole having excellent heat resistance and low dielectric property, and a polybenzox having a high resolution positive pattern forming ability that can be developed in an alkaline aqueous solution when used as a photosensitive resin composition. The present invention provides an oxazo precursor, a positive photosensitive resin composition containing the same, and a pattern forming method using the composition.

As a result of intensive studies to solve the above problems, the present inventors have found a novel polybenzoxazole precursor having a spirobiindane skeleton or a phenylenediisopropylidene skeleton, and have completed the present invention. That is, the present invention is provided by the items described in [1] to [9] below.
[1] A polybenzoxazole precursor having a repeating unit represented by the general formula (1) (wherein X is a divalent organic group, R ₁ and R ₁ ′ are halogen atoms bonded to a benzene ring) Or a hydrocarbon group having 1 to 8 carbon atoms, and when there are a plurality thereof, they may be the same or different, and y and y ′ are each independently an integer of 0 to 3).

[2] A polybenzoxazole precursor having a repeating unit represented by the general formula (2) (wherein X is a divalent organic group, R ₂ and R ₂ ′ are halogen atoms bonded to a benzene ring) Or a hydrocarbon group having 1 to 8 carbon atoms, and when there are a plurality thereof, they may be the same or different, and z and z ′ are each independently an integer of 0 to 3).

[3] A polybenzoxazole precursor having a repeating unit represented by the general formula (3) (wherein X is a divalent organic group, R ₁ , R ₁ ′, R ₂ and R ₂ ′ are A halogen atom bonded to a benzene ring or a hydrocarbon group having 1 to 8 carbon atoms, and when there are a plurality thereof, they may be the same or different, and y, y ′, z and z ′ are independently from 0 3 and m and n are copolymerization ratios, the sum of m and n is 100, and m and n are integers from 1 to 99).

[4] A polybenzoxazole represented by the general formula (4) in which the polybenzoxazole precursor according to the above [1] is thermally or chemically closed (wherein X is a divalent organic group) , R ₁ and R ₁ ′ represent a halogen atom bonded to a benzene ring or a hydrocarbon group having 1 to 8 carbon atoms, and when there are a plurality thereof, they may be the same or different, and y and y ′ are Independently an integer from 0 to 3).

[5] A polybenzoxazole represented by the general formula (5) obtained by thermally or chemically cyclizing the polybenzoxazole precursor according to the above [2] (wherein X is a divalent organic group) , R ₂ and R ₂ ′ represent a halogen atom bonded to a benzene ring or a hydrocarbon group having 1 to 8 carbon atoms, and when there are a plurality thereof, they may be the same or different, and z and z ′ Independently an integer from 0 to 3).

[6] A polybenzoxazole represented by the general formula (6) in which the polybenzoxazole precursor according to the above [3] is thermally or chemically closed (wherein X is a divalent organic group) , R ₁ , R ₁ ′, R ₂ and R ₂ ′ each represent a halogen atom bonded to the benzene ring or a hydrocarbon group having 1 to 8 carbon atoms, and when there are a plurality of them, they may be the same or different from each other , Y, y ′, z and z ′ are each independently an integer of 0 to 3, m and n represent a copolymerization ratio, the sum of m and n is 100, and m and n are 1 to 99).

[7] A photosensitive resin composition comprising the polybenzoxazole precursor according to the above [1] to [3] and a photosensitizer.

[8] A photosensitive resin composition comprising the polybenzoxazole precursor according to the above [1] to [3], a crosslinking agent, and a photosensitizer.

[9] A coating process in which the positive photosensitive resin composition described in [7] above is coated on a substrate and dried at 50 to 160 ° C., and active ultraviolet rays are transmitted through the mask pattern through the obtained coating film. After the exposure, the step of heating at 80 to 350 ° C., the positive pattern development step of developing the exposed coating film by dissolving only the exposed portion using an alkaline aqueous solution, and the developed positive pattern by heat treatment And a ring-closing heat treatment step for forming a benzoxazole positive pattern.

  A polybenzoxazole precursor useful for a positive photosensitive resin composition can be provided, and a cured film of polybenzoxazole obtained therefrom has high heat resistance and low resistance without introducing expensive fluorine atoms. Since it is a positive photosensitive resin composition having a dielectric property and a highly sensitive fine pattern can be formed, an inexpensive positive photosensitive resin composition can be provided.

Polybenzoxazole Precursor The spirobiindane structure-containing o-aminophenol derivative represented by the general formula (7), which is a raw material of the polybenzoxazole precursor of the present invention, is a known method of the spirobiindane compound represented by the general formula (8). To obtain a dinitro compound represented by the general formula (9), and then reducing the nitro group. The spirobiindane compound represented by the general formula (8) is obtained by a known method using bisphenol A as a raw material.

（式中、Ｒ_１およびＲ_１’は、ベンゼン環に結合するハロゲン原子、または炭素数１〜８の炭化水素基を示し、複数ある場合には各々同一でも異なっていてもよく、ｙおよびｙ’は、独立に０から３の整数である）。

(Wherein R ₁ and R ₁ ′ represent a halogen atom bonded to a benzene ring or a hydrocarbon group having 1 to 8 carbon atoms, and when there are a plurality of them, they may be the same or different, and y and y 'Is independently an integer from 0 to 3).

（式中、Ｒ_１、Ｒ_１’、ｙおよびｙ’は、前記同様である）。

(Wherein R ₁ , R ₁ ′, y and y ′ are the same as above).

（式中、Ｒ_１、Ｒ_１’、ｙおよびｙ’は、前記同様である）。

(Wherein R ₁ , R ₁ ′, y and y ′ are the same as above).

  The trinuclear o-aminophenol derivative represented by the general formula (10) can also be obtained in the same manner as described above using commercially available bisphenol M as a raw material.

（式中、Ｒ_２、Ｒ_２’は、ベンゼン環に結合するハロゲン原子、または炭素数１〜８の炭化水素基を示し、複数ある場合には各々同一でも異なっていてもよく、ｚおよびｚ’は、独立に０から３の整数である）。

(Wherein R ₂ and R ₂ ′ represent a halogen atom bonded to a benzene ring or a hydrocarbon group having 1 to 8 carbon atoms, and when there are a plurality of them, they may be the same or different, and z and z 'Is independently an integer from 0 to 3).

  In the general formulas (1) to (3), the divalent organic group represented by X is a residue of a dicarboxylic acid derivative that forms a polyamide structure by reacting with diamine, and the heat resistance of polybenzoxazole. Any carboxylic acid derivative having a structure that does not deteriorate and does not adversely affect the dielectric properties and has a high transmittance in the i-line or g-line region is not limited.

  Specific examples include isophthalic acid, terephthalic acid, 2,2-bis (4-carboxyphenyl) -1,1,1,3,3,3-hexafluoropropane, 4,4′-dicarboxybiphenyl, 4,4. Aromatic dicarboxylic acids such as' -dicarboxydiphenyl ether and bis (4-carboxyphenyl) sulfone, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-adamantanedicarboxylic acid, 1,4 -Alicyclic structures such as adamantyl dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, (4-carboxymethyl-cyclohexyl) acetic acid, (3-carboxymethyl-cyclohexyl) acetic acid, discontinuous aromatic ring structures, etc. Can be used alone or in admixture of two or more.

  In the present invention, the polybenzoxazole precursor having the repeating units represented by the general formulas (1) to (3) can be generally synthesized from a dicarboxylic acid derivative and o-aminophenols by a known method. . Specifically, it can be synthesized by converting the carboxylic acid derivative into a dihalide derivative and then reacting with the o-aminophenol. As the dihalide derivative, a dichloride derivative is preferable. Moreover, a carboxylic acid derivative can also be used as it is by using an activator.

  In the reaction between the dichloride derivative and the diamine, an organic base such as pyridine or triethylamine is usually used as an acid acceptor. As a solvent for the polycondensation reaction for synthesizing the polybenzoxazole precursor used in the present invention, a known organic solvent used for producing a polybenzoxazole precursor can be used.

In particular,
(I) phenolic solvents, phenol, o-chlorophenol, m-chlorophenol, p-chlorophenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol,
(B) N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazo, which are aprotic amide solvents Lysinone, N-methylcaprolactam, hexamethylphosphorotriamide,
(C) Ether solvents such as 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, tetrahydrofuran, bis [2- (2-methoxyethoxy) Ethyl] ether, 1,4-dioxane, diphenyl ether, tetrahydrofuran (d) amine solvents, pyridine, quinoline, isoquinoline, α-picoline, β-picoline, γ-picoline, isophorone, piperidine, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, tributylamine, and (e) other solvents, dimethyl sulfoxide, dimethyl sulfone, sulfolane, diphenyl sulfone, tetramethyl urea, γ-butyrolactone, anisole, water, benzene, Ruene, o-xylene, m-xylene, p-xylene, chlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, bromobenzene, o-dibromobenzene, m-dibromobenzene, p-dibromobenzene, o -Chlorotoluene, m-chlorotoluene, p-chlorotoluene, o-bromotoluene, m-bromotoluene, p-bromotoluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, methanol, ethanol, propanol, isopropanol , Butanol, isobutanol, pentane, hexane, heptane, cyclohexane, dichloromethane, chloroform, carbon tetrachloride, fluorobenzene, methyl acetate, ethyl acetate, butyl acetate, methyl formate, formic acid And ethyl.

  These solvents may be used alone or in combination of two or more. These solvents are preferably used in an amount of 100 to 1000 parts by weight with respect to 100 parts by weight of the polybenzoxazole precursor to be produced.

  The reaction temperature is preferably in the range of −10 ° C. to 100 ° C. as an approximate range, but more preferably in the range of from around the ice-cooling temperature to around 50 ° C. The reaction pressure is sufficient at normal pressure. Furthermore, although reaction time changes with kinds of monomer to be used, a kind of solvent, and reaction temperature, 1-48 hours are preferable. More preferably, it is 1 to 24 hours, particularly preferably 1 to 12 hours, and most preferably 1 to 6 hours from the efficiency of the process.

  The molecular weight of the polybenzoxazole precursor of the present invention is not particularly limited, but is preferably 10,000 or more in terms of weight average molecular weight.

Photosensitive resin composition The photosensitive resin composition of this invention is based on the following (a) and (b).
(A) A polybenzoxazole precursor and a photosensitizer are included.
(B) includes a polybenzoxazole precursor, a crosslinking agent, and a photosensitizer.

Photosensitive resin composition (a)
As the photosensitive agent used in (a), a compound that generates an acid by actinic rays such as ultraviolet rays is used. Examples of the type include o-quinonediazide compounds and aryldiazonium salts. The o-quinonediazide compounds give high sensitivity and high contrast. The chemical structure is not particularly limited, but specifically, a compound represented by the chemical formula group (11) is preferable.

（化学式群中、Ｑは下記の１価の基である）

(In the chemical formula group, Q is the following monovalent group)

  The addition amount of the photosensitizer is preferably 1 to 50 parts by weight with respect to 100 parts by weight of the polybenzoxazole precursor. More preferably, it is 15-40 weight part, More preferably, it is 25-30 weight part.

  The photosensitive resin composition (a) of the present invention can be obtained by using the polybenzoxazole precursor and a photosensitizer as essential components and dissolving them in a solvent.

  Solvents that can be used include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N -Aprotic amide solvents such as methylcaprolactam and hexamethylphosphorotriamide, propylene glycol methyl ether acetate, esters such as ethyl lactate, ketones such as a-butyrolactone, cyclohexanone, diglyme and 2-methoxyethanol, ethers, alcohols It is a system.

  These may be used alone or in combination of two or more. The solvent is preferably used in an amount of 100 to 3000 parts by weight based on 100 parts by weight of the polybenzoxazole to be produced.

  The photosensitive resin composition (a) can be easily formed into a positive pattern simply by adding about 30 parts by weight of a naphthoquinonediazide compound according to a conventional method.

Photosensitive resin composition (b)
The crosslinking agent used in (b) is a vinyl ether group-containing crosslinking agent and is a compound represented by the general formula (13). The central structure of the vinyl ether is not particularly limited, but is preferably a divalent or trivalent compound. Those in which a vinyl ether unit is bonded with an aromatic group, an aliphatic group or the like are preferable.

（式中、ｍは、１以上の整数、Ｒは、１価以上の芳香族基、または脂肪族基を示す）

(In the formula, m represents an integer of 1 or more, and R represents a monovalent or higher-valent aromatic group or aliphatic group.)

  These compounds can be easily synthesized as known literature (for example, Chem. Mater. 1994, 6, 1854-1860). The central structure of vinyl ether (R in the general formula (13)) is not particularly limited, and examples thereof include a compound group represented by the following chemical formula (14). These may be used alone or in combination of two or more.

  The addition amount of the crosslinking agent is 1 to 50 parts by weight, more preferably 5 to 20 parts by weight, and still more preferably 10 to 18 parts by weight with respect to 100 parts by weight of the polybenzoxazole precursor.

The photosensitive agent used in the photosensitive agent (b) of (b) is preferably one that decomposes to an active ray such as ultraviolet rays and generates an acid, and a known photosensitive agent can be used. Specific examples include, for example, seven compound groups represented by chemical formula groups (15) to (21) as shown below, and these compounds are more preferable in the present invention. The structure is not limited to the following as long as it decomposes and generates an acid efficiently. Moreover, these can be used individually or in mixture.

  The addition amount of the photosensitizer is preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the polybenzoxazole precursor. More preferably, 0.5 to 10 parts by weight, and still more preferably 3 to 8 parts by weight are added. Within the above range, the sensitivity to ultraviolet rays is high, and the properties of the coating film are preferable.

  The photosensitive resin composition (b) of the present invention can be obtained by dissolving the polybenzoxazole precursor, the crosslinking agent, and the photosensitive agent in a solvent, and the solvent used is the above-described photosensitive property. The same as in the case of the resin composition (a).

  The photosensitive resin compositions (a) and (b) of the present invention include any other components other than the essential components depending on the purpose, such as a sensitizer, a leveling agent, a coupling agent, and a monomer. , Oligomers, stabilizers, wetting agents, pigments, dyes and the like.

  The method for producing the photosensitive resin compositions (a) and (b) of the present invention is not particularly limited, and any known method may be applied, but if necessary, a positive photosensitive resin composition In the final step of the product, it is preferable to add a step of filtration through a filtration membrane such as a Teflon (registered trademark) filter and degassing under reduced pressure.

  A photosensitive mechanism using the resin composition (b) of the present invention will be described.

  The compound having a phenolic hydroxyl group and a vinyl ether moiety of the polybenzoxazole precursor represented by the general formulas (1) to (3) forms an acetal bond by heat drying after spin coating on the substrate. , Take a cross-linked structure. Next, by irradiating and heating actinic rays such as ultraviolet rays, in the actinic ray exposure part, the photoacid generating photosensitive agent is decomposed, acid is generated and diffused, and the acetal bond is cleaved to regenerate the phenolic hydroxyl group. The hydroxyl acid of this polymer has moderate solubility in an aqueous alkali solution. As a result, only the portion irradiated with actinic rays such as ultraviolet rays shows high solubility in the aqueous alkali solution, and the unirradiated portion is insoluble. So it doesn't melt at all. By using this concept of chemical amplification type, the amount of additives other than resin can be reduced, and a highly sensitive positive pattern can be formed.

Positive Pattern Formation Method A positive pattern formation method using the photosensitive resin composition obtained according to the present invention will be described.

  When considering application to a semiconductor device, first, the resin composition is coated on a wafer using a spin coater, and then the coating film is dried at 50 to 160 ° C., preferably 70 to 140 ° C. .

  The obtained coating film is passed through a mask on which a pattern is drawn and irradiated with active ultraviolet rays such as 365 nm and 436 nm. Next, the coating film is heated again at 110 to 200 ° C., preferably 120 to 180 ° C., and then the coating film is subjected to an alkaline aqueous solution, for example, an inorganic alkali such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, or ammonia. Primary amines such as aqueous solution, ethylamine and n-propylamine, secondary amines such as diethylamine and di-n-propylamine, tertiary amines such as triethylamine and methyldimethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, Using an aqueous solution of a quaternary amine such as tetramethylammonium hydroxide or tetraethylammonium hydroxide, only the actinic ray irradiated area is dissolved and developed, and rinsed with pure water.

  As a developing method, methods such as spraying, paddle, dipping, and ultrasonic waves can be used. Thereby, a desired positive pattern can be obtained on the target wafer. Furthermore, the photosensitive resin composition is cured by a heat treatment in which the coating film is heated at 80 to 350 ° C. The heat treatment temperature by heating is preferably 150 to 350 ° C, more preferably 200 to 350 ° C, and particularly preferably 300 to 350 ° C. The heat treatment time by heating varies depending on the treatment temperature and film thickness, but is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours, and most preferably 1 to 6 hours. Moreover, it is also preferable to heat in steps by combining these temperatures and times. For example, heat treatment can be performed at 150 ° C. for 1 hour and then at 250 ° C. for 1 hour. In this way, a polybenzoxazole film having excellent film characteristics can be formed.

[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not restrict | limited at all by this. Each evaluation method in the examples is shown below.
i) Glass transition temperature (Tg): Measured by DSC (Differential Scanning Calorimeter, DSC-60 manufactured by Shimadzu Corporation) from 25 ° C. to 350 ° C. at a heating rate of 10 ° C./min.
ii) Weight average molecular weight (Mw): Measured by gel permeation chromatography (GPC) in terms of polystyrene using a Jasco 2000 system manufactured by JASCO Corporation using chloroform as an eluent.
iii) Dielectric constant and dielectric loss tangent: Measured by an automatic equilibrium bridge method using Precision LCR meter HP4284A manufactured by Agilent Technologies.

[Synthesis Example 1] Synthesis of o-aminophenol of chemical formula (22)

  15.42 g (0.05 mol) of 6,6′-dihydroxy-3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane (SPI) was dissolved in 43.26 g of monochlorobenzene and 65% nitric acid 9.7g (2 equivalent with respect to 0.1 mol / SPI) was dripped at 15 degreeC. After reacting at 15 to 20 ° C. for 2 hours, the mixture was neutralized with 5% aqueous sodium hydrogen carbonate solution. After further washing with water, the organic layer was separated and concentrated, and washed with hot isopropanol to obtain the desired product.

  To 5.98 g (0.015 mol) of this compound, 1.856 g (15 wt%) of 5% palladium / carbon, 18 g of dimethylacetamide and 6 g of ethanol were added and reacted for 12 hours. After completion of the reaction, palladium / carbon was removed by filtration, concentrated, and then crystallized by adding water. The yield was 60% and the melting point was 277.1 ° C.

[Synthesis Example 2] Synthesis of o-aminophenol of chemical formula (23)

Instead of 6,6′-dihydroxy-3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane (SPI) in Synthesis Example 1, 4,4 ′-((p-phenylene) diisopropylidene ) Synthesis was performed in the same manner except that diphenol was used.
The yield was 60% and the melting point was 248.1 ° C.

Example 1 Synthesis of Polybenzoxazole Precursor of Formula (24)

（式中、ｎは重合度を示す）

(Where n represents the degree of polymerization)

  In a reaction flask equipped with a stirrer and a nitrogen introduction tube, 4.52 g (0.012 mol) of the compound represented by the chemical formula (22) and 1.12 g (0.026 mol) of lithium chloride were added to N-methyl-2-pyrrolidone (NMP). ) It was dissolved in 28 mL and cooled on ice. To this, 2.44 g (0.012 mol) of isophthalic acid chloride was added, stirred for 1 hour in an ice bath and 24 hours at room temperature, and then discharged into water to obtain a polymer. The weight average molecular weight was 12000. 1H-NMR of the synthesized polybenzoxazole precursor, an infrared absorption spectrum, and the infrared absorption spectrum of the thermosetting film obtained by heat-processing this at 350 ° C./1 hour are shown in FIGS. The logarithmic viscosity was 0.30 dL / g, and the glass transition temperature was not observed below the decomposition start temperature.

Example 2 Synthesis of Polybenzoxazole Precursor of Formula (25)

（式中、ｎは重合度を示す）

(Where n represents the degree of polymerization)

  Polymerization was carried out in the same manner as in Example 1 except that o-aminophenol represented by the general formula (24) was used instead of the compound of the chemical formula (22) in Example 1. The weight average molecular weight was 18000. 4 to 6 show the 1H-NMR, infrared absorption spectrum of the synthesized polybenzoxazole precursor and the infrared absorption spectrum of the thermosetting film obtained by heat treatment at 350 ° C./1 hour. The logarithmic viscosity was 0.36 dL / g, and the glass transition temperature was not observed below the decomposition start temperature.

[Example 3] Synthesis of polybenzoxazole precursor of formula (26) (m = 70, n = 30)

（式中、ｍとｎは共重合比を示す）

(Wherein m and n are copolymerization ratios)

  Polymerization was carried out in the same manner as in Example 2 except that two kinds of o-aminophenol and compounds represented by chemical formula (22) and chemical formula (23) were used at a molar ratio of 70:30. The weight average molecular weight was 11000. The logarithmic viscosity was 0.31 dL / g, and the glass transition temperature was not observed below the decomposition start temperature.

[Example 4] Synthesis of polybenzoxazole precursor of formula (27) (m = 30, n = 70)

（式中、ｍとｎは共重合比を示す）

(Wherein m and n are copolymerization ratios)

  Polymerization was carried out in the same manner as in Example 3 except that two kinds of o-aminophenol and compounds represented by chemical formula (22) and chemical formula (23) were used at a molar ratio of 30:70. The weight average molecular weight was 11000. The logarithmic viscosity was 0.31 dL / g, and the glass transition temperature was not observed below the decomposition start temperature.

[Examples 5 to 8]
1.2 g of the polybenzoxazole precursor obtained in Examples 1 to 4 was dissolved in 4 mL of cyclohexanone, and 0.36 g of naphthoquinone diazide which is a photosensitizer of the chemical formula (28) was added. This solution was filtered using a 1 μm pore Teflon (registered trademark) filter to obtain a photosensitive resin composition as Samples 1-4.

Samples 1 to 4 were coated on a 4-inch silicon wafer by a spin coater and dried in a drying oven at 100 ° C. for 10 minutes to obtain a 3 μm coating film. This coating film was irradiated with a test pattern with an energy of 220 to 240 mJ / cm ² by a broadband ultraviolet exposure machine. Next, paddle development was performed for 15 seconds with a 2.38 wt% TMAH (tetramethylammonium hydride) aqueous solution, followed by washing with pure water.

  By this operation, a positive relief pattern in which only the ultraviolet irradiation part of the coating film was dissolved could be obtained. When the obtained pattern was observed with an optical microscope, it was confirmed that a pattern of 12 to 20 μm was formed. Furthermore, this pattern was heat-treated at 350 ° C. for 1 hour to complete the polybenzoxazolization of the coating film. The obtained film maintained good pattern formability. Table 1 shows the results of the characteristic evaluation of Samples 1 to 4.

[Examples 9 to 12]
1.2 g of the polybenzoxazole precursor obtained in Examples 1 to 4 was dissolved in 4 mL of cyclohexanone, and 0.06 g of a photoacid generator and 0.18 g of a crosslinking agent, which are photosensitizers of the chemical formula (29), were added. This solution was filtered using a 1 μm pore Teflon (registered trademark) filter to obtain a photosensitive resin composition as Samples 5-8.

Samples 5 to 8 were coated on a 4-inch silicon wafer with a spin coater and dried in a drying oven at 120 ° C. for 5 minutes to obtain a 3 μm coating film. This coating film was irradiated with a test pattern with an energy of 150 to 180 mJ / cm ² by a broadband ultraviolet exposure machine, and subsequently heated at 120 ° C. for 5 minutes. Next, paddle development was performed for 60 seconds with a 2.38% aqueous solution of TMAH (tetramethylammonium hydride), followed by washing with pure water.

  By this operation, a positive relief pattern in which only the ultraviolet irradiation part of the coating film was dissolved could be obtained. When the obtained pattern was observed with an optical microscope, it was confirmed that a pattern of up to 10 μm was formed. Furthermore, this pattern was performed at 350 ° C. for 1 hour to complete the polybenzoxazolation of the coating film. The obtained film maintained good pattern formability. The characteristics of Samples 5 to 8 are shown in Table 2.

[Comparative Example 1]
In the same manner as in Example 1, 4,4 ′-(hexafluoroisopropylidene) bis (o-aminophenol) was used in place of the compound represented by the chemical formula (22) used in Example 1 as o-aminophenol. The corresponding polybenzoxazole precursor was synthesized. Furthermore, it carried out similarly to Examples 5-8, and obtained the photosensitive resin composition as the sample 9, and performed the evaluation. The results are shown in Table 3. The resolution is 5 μm, which is equivalent to 10 μm, and since it has a glass transition temperature, it was found that it cannot be used above that temperature.

  As described above, it has been found that the photosensitive resin composition obtained in the present invention is excellent in sensitivity and heat resistance while maintaining a low dielectric property while having a structure not using fluorine.

  Since the positive photosensitive resin composition of the present invention reacts with ultraviolet rays in a chemical amplification manner, a positive pattern with high contrast and high sensitivity can be obtained. The present invention can be used for applications that require heat resistance and fine processing, such as insulating films for printed wiring boards and semiconductor coating films.

2 is a 1H-NMR spectrum of a polybenzoxazole precursor film obtained in Example 1. FIG.

2 is an infrared absorption spectrum of the polybenzoxazole precursor film obtained in Example 1.

2 is an infrared absorption spectrum of polybenzoxazole obtained in Example 1.

2 is a 1H-NMR spectrum of a polybenzoxazole precursor film obtained in Example 2. FIG.

3 is an infrared absorption spectrum of the polybenzoxazole precursor film obtained in Example 2.

2 is an infrared absorption spectrum of polybenzoxazole obtained in Example 2.

Claims (9)

A polybenzoxazole precursor having a repeating unit represented by the general formula (1) (wherein X is a divalent organic group, R ₁ and R ₁ ′ are a halogen atom bonded to a benzene ring, or carbon A hydrocarbon group having a number of 1 to 8 and a plurality of hydrocarbon groups may be the same or different, and y and y ′ are each independently an integer of 0 to 3).

A polybenzoxazole precursor having a repeating unit represented by the general formula (2) (wherein X is a divalent organic group, R ₂ and R ₂ ′ are a halogen atom bonded to a benzene ring, or carbon A hydrocarbon group having a number of 1 to 8 and a plurality thereof may be the same or different, and z and z ′ are each independently an integer of 0 to 3).

A polybenzoxazole precursor having a repeating unit represented by the general formula (3) (wherein X is a divalent organic group, R ₁ , R ₁ ′, R ₂ and R ₂ ′ are A halogen atom to be bonded or a hydrocarbon group having 1 to 8 carbon atoms, and when there are a plurality thereof, they may be the same or different, and y, y ′, z and z ′ are each independently an integer of 0 to 3 And m and n represent the copolymerization ratio, the sum of m and n is 100, and m and n are integers from 1 to 99).

A polybenzoxazole represented by the general formula (4) obtained by thermally or chemically cyclizing the polybenzoxazole precursor according to claim 1, wherein X is a divalent organic group, R ₁ and R ₁ ′ represents a halogen atom bonded to a benzene ring or a hydrocarbon group having 1 to 8 carbon atoms, and when there are a plurality thereof, they may be the same or different, and y and y ′ are independently from 0 3).

A polybenzoxazole represented by the general formula (5) obtained by thermally or chemically cyclizing the polybenzoxazole precursor according to claim 2 (wherein X is a divalent organic group, R ₂ and R ₂ ′ represents a halogen atom bonded to a benzene ring or a hydrocarbon group having 1 to 8 carbon atoms, and when there are a plurality thereof, they may be the same or different, and z and z ′ are independently from 0 3).

A polybenzoxazole represented by the general formula (6) in which the polybenzoxazole precursor according to claim 3 is thermally or chemically closed (wherein X is a divalent organic group, R ₁ , R ₁ ′, R ₂ and R ₂ ′ each represent a halogen atom bonded to a benzene ring or a hydrocarbon group having 1 to 8 carbon atoms, and when there are a plurality thereof, they may be the same or different, and y, y ', Z and z' are each independently an integer of 0 to 3, m and n are copolymerization ratios, the sum of m and n is 100, and m and n are integers of 1 to 99. is there).

  A photosensitive resin composition comprising the polybenzoxazole precursor according to claim 1 and a photosensitizer.   A photosensitive resin composition comprising the polybenzoxazole precursor according to claim 1, a crosslinking agent, and a photosensitive agent. The positive photosensitive resin composition according to claim 1 is coated on a substrate and dried at 50 to 160 ° C., and the obtained coating film is exposed to active ultraviolet rays through a mask pattern. Thereafter, a step of heating at 80 to 350 ° C., a positive pattern developing step of developing the exposed coating film by dissolving only the exposed portion using an alkaline aqueous solution, and heat-treating the developed positive pattern to polybenzoxazole And a ring-closing heat treatment step for forming the positive pattern.

Images