JP2000128987A - 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 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 group of formula II [R3 is a fluorocycloalkyl of formula III ((k) is 3-7); R4 to R6 are each H, a fluorocycloalkyl of formula III, F or univalent organic group]; Y is a bivalent organic group}, obtained, for example, by acid chloride method or condensation reaction between a bisaminophenol of formula IV 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 a divalent organic group represented by the general formula (2) or (3), and Y represents a divalent or higher valent organic group. )

[0008]

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Wherein R ₃ is a fluorocycloalkyl group represented by the general formula (4), R _{4 to} R ₆ are H, a fluorocycloalkyl group represented by the general formula (4), F or It is a monovalent organic group and may be the same or different.)

[0010]

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Wherein R ₇ is a fluorocycloalkyl group represented by the general formula (4), R _{8 to} R ₁₀ are H, a fluorocycloalkyl group represented by the general formula (4), F or It is a monovalent organic group and may be the same or different.)

[0012]

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(In the formula, k represents an integer of 3 to 7.)
[2] A polybenzoxazole having a structure in which the polybenzoxazole precursor according to [1] is dehydrated and closed.

[0014]

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 is a method for preparing a bisaminophenol compound represented by the general formula (5) and a dicarboxylic acid represented by the general formula (6) by an acid chloride method or dehydration of polyphosphoric acid or dicyclohexyl dicarbodiimide. It can be obtained by a method such as a condensation reaction in the presence of a condensing agent.

[0015]

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(In the formula, 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 a divalent organic group represented by the general formula (2) or (3), and Y represents a divalent or higher valent organic group. )

[0017]

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Wherein R ₃ is a fluorocycloalkyl group represented by the general formula (4), R _{4 to} R ₆ are H, a fluorocycloalkyl group represented by the general formula (4), F or It is a monovalent organic group and may be the same or different.)

[0019]

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(Wherein R ₇ is a fluorocycloalkyl group represented by the general formula (4), R _{8 to} R ₁₀ are H, a fluorocycloalkyl group represented by the general formula (4), F or It is a monovalent organic group and may be the same or different.)

[0021]

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(In the formula, k represents an integer of 3 to 7.)

[0023]

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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 (5) include, but are not limited to, the compounds of the formulas (7) to (20). These bisaminophenol compounds are used alone,
Or they can be used in combination. Also, 4,
Bis other than the bisaminophenol compound represented by the general formula (5) such as 4′-diamino-3,3′-dihydroxybiphenyl and 2,2′-bis (3-amino-4-hydroxyphenyl) hexafluoropropane It is possible to use an aminophenol compound in combination as long as the performance is not impaired.

[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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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 then dissolved in the presence of an acid acceptor such as pyridine. Then, a polybenzoxazole precursor can be obtained by reacting with dicarboxylic acid chloride at −30 ° C. to room temperature. The polybenzoxazole of the present invention can be obtained by subjecting the thus obtained polybenzoxazole precursor to a dehydration / ring-closing 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 can be used as a photosensitive resin composition by using a naphthoquinonediazide compound as a precursor and a photosensitive agent.

The polybenzoxazole precursor of the present invention is usually dissolved in a solvent and used in the form of a varnish. As the solvent, 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, methyl lactate, ethyl lactate, butyl lactate ,
Methyl-1,3-butylene glycol acetate, 1,
One or a mixture of two or more of 3-butylene glycol-3-monomethyl ether, methyl pyruvate, ethyl pyruvate, methyl-3-methoxypropionate and the like can be used.

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.

[0035]

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. 14.51 g of a bisaminophenol compound represented by the formula (7) (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.

The polybenzoxazole precursor was converted to N-
It was dissolved in methyl-2-pyrrolidone 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 at 70 ℃ 1
After drying for an hour, the film was peeled off to obtain a polybenzoxazole precursor film having a thickness of 20 μm. The film was fixed with a metal frame, and 150 ° C./30 minutes, 250 ° C./30 minutes, 350 ° C.
The mixture was heated under a nitrogen atmosphere in the order of ° 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. 14.51 g (0.02 mol) of the bisaminophenol compound represented by the formula (7)
Was replaced with 23.05 g (0.02 mol) of a bisaminophenol compound represented by the formula (10) by 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 14.51 g (0.02 mol) of the bisaminophenol compound represented by the formula (7), 18.81 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 In place of 14.51 g (0.02 mol) of the bisaminophenol compound represented by the formula (7), 24.57 g (0.02 mol) of the bisaminophenol compound represented by the formula (20) A polybenzoxazole was prepared in the same manner as in Example 1 except that
An evaluation was performed.

Example 5 17.29 g (0.015 mol) of a bisaminophenol compound represented by the formula (18) instead of 14.51 g (0.02 mol) of the bisaminophenol compound represented by the formula (7) ) 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 4.32 g of 3,3′-amino-4,4′-hydroxybiphenyl (0%) instead of 14.51 g (0.02 mol) of the bisaminophenol compound represented by the formula (7) 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.

[0044]

[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 low dielectric constants and are 2.0 to 2.0.
3, indicating good properties such as high heat resistance 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, and thus has a higher dielectric constant than Examples 1 to 5. No values below 5 were obtained.

In Comparative Example 2, since the polyimide prepared using the polyimide precursor was used, the dielectric constant and the water absorption were higher than those of Examples 1 to 5.

[0048]

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.

Claims (2)

[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 a divalent organic group represented by the general formula (2) or (3), and Y represents a divalent or higher valent organic group. ) (Wherein, R ₃ is a fluorocycloalkyl group represented by the general formula (4), R _{4 to} R ₆ are H, a fluorocycloalkyl group represented by the general formula (4), F or monovalent These are organic groups and may be the same or different.) (Wherein, R ₇ is a fluorocycloalkyl group represented by the general formula (4), R _{8 to} R ₁₀ are H, a fluorocycloalkyl group represented by the general formula (4), F or monovalent These are organic groups and may be the same or different from each other.) (In the formula, k represents an integer of 3 to 7.) 2. A polybenzoxazole having a structure in which the polybenzoxazole precursor according to claim 1 is dehydrated and closed.