JP2000128986A - Polybenzoxazole precursor and polybenzoxazole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polybenzoxazole precursor for the corresponding heat- resistant resin with excellent electrical properties, thermal properties and low water absorptivity, useful in semiconductor applications by including repeating units of a specific structure. SOLUTION: This polybenzoxazole precursor is composed of a repeating unit of formula I [(n) is 1-1,000; R1 and R2 are each a fluoroalkyl group of CmF2m+1 ((m) is 1-10); X is a bivalent or higher valent fluorogroup-contg. aromatic group; Y is a bivalent or higher valent organic group], obtained, for example, by acid chloride method or condensation reaction between a bisaminophenol of formula II (e.g. a compound of formula III) and a dicarboxylic acid of the formula HOOC-Y COOH (e.g. isophthalic acid) in the presence of a dehydrocondensation agent such as a polyphosphoric acid or dicyclohexyldicarbodiimide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to electrical characteristics, thermal characteristics,
This is related to polybenzoxazole resins with excellent mechanical and physical properties, such as interlayer insulating films for semiconductors, protective films, interlayer insulating films for multilayer circuits, cover coats for flexible copper clad plates, solder resist films, liquid crystal alignment films, etc. Applicable as

[0002]

2. Description of the Related Art Among the characteristics required for insulating materials for semiconductors, electrical characteristics, particularly dielectric constant and heat resistance, are the most important characteristics. In order to make these two characteristics compatible, an organic insulating film having high heat resistance is expected. For example, a conventionally used inorganic insulating film such as silicon dioxide has high heat resistance, but has a high dielectric constant, and it is becoming difficult to achieve the above-mentioned characteristics at the same time. An organic insulating film represented by a polyimide resin has excellent electrical properties and heat resistance, and can achieve both of the two properties.
It is used for liquid crystal alignment films and the like. However, with the recent advancement of functions and performance of semiconductors, remarkable improvements in electrical characteristics and heat resistance have been required, so that even higher performance resins have been required. In particular, a low dielectric constant material having a dielectric constant of less than 2.5 is expected, and even in a polyimide resin, it is possible to achieve both electrical characteristics and heat resistance by introducing fluorine and a trifluoromethyl group into a polymer. Attempts have been made, but not to the required level at this time.

[0003] Among resins other than polyimide resins, polybenzoxazole resins are expected. The polyimide resin has two bad carboxyl groups on the imide ring, which adversely affects the electrical characteristics. Therefore, polybenzoxazole resins are generally very useful resins because they have better electrical properties and the same heat resistance as polyimide resins. However, the required level of electric characteristics is extremely high, and the level of the conventional polybenzoxazole resin has not reached the required level. Furthermore, low water absorption is one of the important characteristics. This is because when the resin absorbs water, one or both of the electrical characteristics and the heat resistance deteriorate. Also in this respect, polybenzoxazole resin is generally superior to polyimide resin because it exhibits lower water absorption.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-resistant resin excellent in electric properties, heat resistance and low water absorption.

[0005]

The present invention provides [1] a polybenzoxazole precursor having a repeating unit represented by the general formula (1):

[0006]

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(Wherein, n represents an integer of 1 to 1000. R ₁ and R ₂ are fluoroalkyl groups represented by C _m F _{2m + 1,} which may be the same or different. m is 1
Shows an integer from 10 to 10. X represents an aromatic group having a divalent or higher valent fluoro group, and Y represents a divalent or higher valent organic group. Wherein [2] X is represented by the general formula (2).

[0008]

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(Wherein R ₃ is a fluoroalkyl group represented by C _k F _{2k + 1} , R _{4 to} R ₆ are H or a fluoroalkyl group represented by C _k F _{2k + 1} , They may be the same or different, and k represents an integer of 0 to 10.)
[3] wherein R ₃ is CF ₃ , one of R _{4 to} R ₆ is CF ₃ , and the remaining two of R _{4 to} R ₆ are H [2]
The polybenzoxazole precursor described in [4] X
Is a polybenzoxazole precursor according to [1], represented by the general formula (3):

[0010]

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(Wherein R ₇ is a fluoroalkyl group represented by C _k F _{2k + 1} , R _{8 to} R ₁₀ are H or a fluoroalkyl group represented by C _k F _{2k + 1} , They may be the same or different, and k represents an integer of 0 to 10.)
[5] A polybenzoxazole having a structure in which the polybenzoxazole precursor according to any one of the above [1] to [4] is dehydrated and closed.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have made intensive studies in view of the above-mentioned conventional problems, and as a result, have found that a polybenzoxazole precursor represented by the general formula (1) and a polybenzoxazole precursor A polybenzoxazole resin having a structure obtained by dehydration ring closure was found, and the present invention was completed. The method for producing a polybenzoxazole precursor according to the present invention comprises the steps of: subjecting a bisaminophenol compound represented by the general formula (4) and a dicarboxylic acid represented by the general formula (5) to an acid chloride method or dehydration of polyphosphoric acid, dicyclohexyl dicarbodiimide, or the like. It can be obtained by a method such as a condensation reaction in the presence of a condensing agent.

[0013]

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(Wherein R ₁ and R ₂ are C _m F _{2m + 1} and may be the same or different. M represents an integer of 1 to 10. X is a divalent or higher fluoro group. Represents an aromatic group having a group.)

[0015]

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(In the formula, Y represents a divalent or higher valent organic group.) Examples of the bisaminophenol compound represented by the general formula (4) include compounds of the formulas (6) to (18). , But is not necessarily limited to these. Among these, the expressions (6) to (15) and (17)
When a bisaminophenol compound represented by the formula (18) or the like is used, particularly good characteristics are obtained, which is preferable. These bisaminophenol compounds can be used alone or in combination. In addition, compounds other than compounds of formulas (6) to (18) such as 4,4'-diamino-3,3'-dihydroxybiphenyl and 2,2'-bis (3-amino-4-hydroxyphenyl) hexafluoropropane It is also possible to use the bisaminophenol compound in combination within a range not to impair the performance.

[0017]

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[0018]

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[0019]

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[0020]

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Examples of dicarboxylic acids include isophthalic acid, terephthalic acid, 3-fluoroisophthalic acid, 2-fluoroisophthalic acid, 3-fluorophthalic acid, 2-fluorophthalic acid, 2-fluoroterephthalic acid, 2,4,4
5,6-tetrafluoroisophthalic acid, 3,4,5,6
-Tetrafluorophthalic acid, 2,2-bis (4-carboxyphenyl) hexafluoropropane, perfluorosuberic acid, 2,2'-bis (trifluoromethyl)-
Examples thereof include 4,4′-biphenylenedicarboxylic acid and 4,4′-oxybisbenzoic acid, but are not necessarily limited thereto. It is also possible to use two or more carboxylic acids in combination.

As an example of the synthesis of a polybenzoxazole precursor by the acid chloride method, a bisaminophenol compound is usually dissolved in a polar solvent such as N-methyl-2-pyrrolidone, and the solution is dissolved in the presence of an acid acceptor such as pyridine. To react with tetrafluoroisophthalic chloride at -30 ° C to room temperature to obtain a polybenzoxazole precursor. Polybenzoxazole resin of the present invention,
The polybenzoxazole precursor thus obtained can be subjected to a condensation reaction by heating or treating with a dehydrating agent as in a conventional method. If necessary, various additives such as surfactants and coupling agents are added, and interlayer insulating films for semiconductors, protective films, interlayer insulating films for multilayer circuits, cover coats for flexible copper clad boards, solder resist films, It can be used as a liquid crystal alignment film or the like.
Further, the polybenzoxazole resin in the present invention,
By using a naphthoquinonediazide compound as the precursor and the photosensitizer, it can be used as a photosensitive resin composition.

It is preferable that the polybenzoxazole precursor of the present invention is usually dissolved in a solvent and used in the form of a varnish. Examples of the solvent include N-methyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylacetamide, dimethyl sulfoxide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, Propylene glycol monomethyl ether acetate, methyl lactate, ethyl lactate,
One or two or more of butyl lactate, methyl-1,3-butylene glycol acetate, 1,3-butylene glycol-3-monomethyl ether, methyl pyruvate, ethyl pyruvate, methyl-3-methoxypropionate, etc. They can be used in combination.

In the method of using the polybenzoxazole precursor of the present invention, the precursor is dissolved in the above-mentioned solvent and applied to a suitable support, for example, a glass, metal, silicone wafer or ceramic substrate. The coating method is spin coating using a spinner, spray coating using a spray coater,
Immersion, printing, roll coating, etc. are selected. After forming a coating film in this way, it is preferable to perform a heat treatment to convert it to polybenzoxazole before use. Further, by selecting a dicarboxylic acid component, it can be used as a polybenzoxazole which is soluble in a solvent.

[0025]

EXAMPLES The present invention will be described in detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

(Example 1) 4,4'-Hexafluoroisopropylidenediphenyl-1,1'dicarboxylic acid 25
g, 45 ml of thionyl chloride and 0.5 ml of dry DMF were placed in a reaction vessel and reacted at 60 ° C. for 2 hours. After completion of the reaction, excess thionyl chloride was distilled off by heating and reduced pressure. The precipitate was recrystallized using hexane to obtain 4,4 ′
-Hexafluoroisopropylidene diphenyl-1,
1 ′ dicarboxylic acid chloride was obtained. 13.29 g of a bisaminophenol compound represented by the formula (9) (0.02 m
ol) was dissolved in 100 g of dried dimethylacetamide, and 3.96 g (0.05 mol) of pyridine was added.
Under dry nitrogen at −15 ° C., 8.46 g (0.02 g) of 4,4′-hexafluoroisopropylidenediphenyl-1,1 ′ dicarboxylic acid chloride was added to 50 g of dimethylacetamide.
mol) was added dropwise over 30 minutes. After completion of the dropwise addition, the mixture was returned to room temperature and stirred at room temperature for 5 hours. Thereafter, the reaction solution was dropped into 1000 ml of distilled water, and the precipitate was collected and dried to obtain a polybenzoxazole precursor.

This polybenzoxazole precursor is converted to N-
It was dissolved in methyl-2-pyrrolidone and filtered through a Teflon (registered trademark) filter having a pore size of 0.2 μm to obtain a varnish.
This varnish was applied on a glass plate using a doctor knife having a gap of 300 μm. Then, in the oven 70
The resultant was dried at a temperature of 1 ° C. for 1 hour and peeled off to obtain a polybenzoxazole precursor film having a thickness of 20 μm. The film was fixed with a metal frame, 150 ° C./30 minutes, 250 ° C./30 minutes, 3
Heating was performed under a nitrogen atmosphere in the order of 50 ° C./30 minutes to obtain polybenzoxazole. Various characteristics were evaluated using this test film, and the results are summarized in Table 1.

Example 2 50 g of 1,2,3,5-tetrafluoro-2,6-dicyanobenzene was added to 250 g of 65% aqueous sulfuric acid. After heating to dissolve, the mixture was heated under reflux conditions for 3 hours. The precipitated crystals were filtered by suction, and the collected crystals were washed with concentrated hydrochloric acid and air-dried. Thus, tetrafluoroisophthalic acid was obtained. 13.29 g (0.02 mol) of the bisaminophenol compound represented by the formula (9)
In place of the above, 14.57 g (0.02 mol) of the bisaminophenol compound represented by the formula (11) was added to 4,4′-
Hexafluoroisopropylidene diphenyl-1,1 '
Instead of 8.46 g (0.02 mol) of dicarboxylic acid chloride, 5.42 g (0.02 mol) of tetrafluoroisophthalic chloride synthesized from tetrafluoroisophthalic acid was used.
mol)), a polybenzoxazole was prepared and evaluated in the same manner as in Example 1.

Example 3 Instead of 13.29 g (0.02 mol) of the bisaminophenol compound represented by the formula (9), 16.09 g (0.02 mol) of the bisaminophenol compound represented by the formula (17) A polybenzoxazole was prepared in the same manner as in Example 1 except that
An evaluation was performed.

(Example 4) Instead of 13.29 g (0.02 mol) of the bisaminophenol compound represented by the formula (9), 16.25 g (0.02 mol) of the bisaminophenol compound represented by the formula (18) A polybenzoxazole was prepared in the same manner as in Example 1 except that
An evaluation was performed.

Example 5 Instead of 13.29 g (0.02 mol) of the bisaminophenol compound represented by the formula (9), 12.31 g (0.015 mol) of the bisaminophenol compound represented by the formula (16) ) And 2.51 g of 2,2′-bis (3-amino-4-hydroxy-5-trifluorophenyl) hexafluoropropane (0.001 g)
Polybenzoxazole was prepared and evaluated in the same manner as in Example 1 except that 5 mol) was used.

Comparative Example 1 Instead of 13.29 g (0.02 mol) of the bisaminophenol compound represented by the formula (9), 4.32 g of 3,3'-amino-4,4'-hydroxybiphenyl (0 Polybenzoxazole was prepared in the same manner as in Example 1 except that
An evaluation was performed.

Comparative Example 2 2,2-bis [4,4'-
(4-aminophenoxy) phenyl] propane 10.3
6 g (0.02 mol) is dissolved in 150 g of dried N-methyl-2-pyrrolidone. The solution was cooled to 10 ° C. under dry nitrogen, and 4.36 pyromellitic dianhydride was added. Five hours after the introduction, the temperature was returned to room temperature, and the mixture was stirred at room temperature for 2 hours to obtain a polyimide precursor solution. The polyimide precursor was filtered through a Teflon filter having a pore size of 0.2 μm to obtain a varnish. This varnish is placed on a glass plate with a gap of 300.
The coating was performed using a μm doctor knife. Then, it is dried in an oven at 70 ° C for 1 hour, peeled off, and the film thickness is 20 μm.
Was obtained. The film was fixed with a metal frame, 150 ° C./30 minutes, 250 ° C./30 minutes, 3
Heating was performed under a nitrogen atmosphere in the order of 50 ° C./30 minutes to obtain a polyimide. This polyimide was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results of the examples and the comparative examples.

[0034]

[Table 1]

From the results shown in Table 1, all of the polybenzoxazoles prepared using the polybenzoxazole precursors of the present invention of Examples 1 to 5 have a low dielectric constant, which is lower than 2.5, and furthermore a low heat resistance. It showed good characteristics of high and low water absorption.

In Comparative Example 1, although it is a polybenzoxazole, it does not have the repeating unit represented by the general formula (1) of the present invention. No values below 5 were obtained.

In Comparative Example 2, since a polyimide prepared using a polyimide precursor was used, only higher values of dielectric constant and water absorption were obtained as compared with Examples 1 to 5.

[0038]

The polybenzoxazole precursor and polybenzoxazole of the present invention relate to a resin having excellent electrical properties, heat resistance and physical properties. Therefore, these properties are required in various fields such as interlayer insulating films for semiconductors, protective films, interlayer insulating films for multilayer circuits, cover coats for flexible copper clad plates, solder resist films, and liquid crystal alignment films. It is a polymer material.

Continued on the front page F-term (reference) 4J043 PA02 PA19 PB24 PC145 PC146 PC155 PC156 QB15 QB21 QB23 QB34 RA52 SA06 SA71 SB01 TA12 TA26 TB01 UA122 UA131 UA132 UA141 UA151 UB061 UB062 UB121 VA012 VA052 VA092 VA101 XA06 Z06 Z08 ZA60 ZB02 ZB50

Claims (5)

[Claims] 1. A polybenzoxazole precursor having a repeating unit represented by the general formula (1). Embedded image (In the formula, n represents an integer of 1 to 1000. R ₁ , R ₂
Is a fluoroalkyl group represented by C _m F _{2m + 1,} which may be the same or different. m represents an integer of 1 to 10. X represents an aromatic group having a divalent or higher valent fluoro group, and Y represents a divalent or higher valent organic group. ) 2. The method according to claim 1, wherein X is represented by the general formula (2).
The polybenzoxazole precursor according to the above. Embedded image (In the formula, R ₃ is a fluoroalkyl group represented by C _k F _{2k + 1} , and R _{4 to} R ₆ are H or a fluoroalkyl group represented by C _k F _{2k + 1} and are the same as each other. And k represents an integer of 0 to 10.) Wherein one of R ₃ is CF ₃ R ₄ to R ₆ is CF _3, the polybenzoxazole precursor of the rest two claim 2, wherein the H of R ₄ to R _6. 4. The method according to claim 1, wherein X is represented by the general formula (3).
The polybenzoxazole precursor according to the above. Embedded image (In the formula, R ₇ is a fluoroalkyl group represented by C _k F _{2k + 1} , and R _{8 to} R ₁₀ are H or a fluoroalkyl group represented by C _k F _{2k + 1} and are the same as each other. And k represents an integer of 0 to 10.) 5. A polybenzoxazole having a structure in which the polybenzoxazole precursor according to claim 1 is dehydrated and ring-closed.