JPH11322920A - Highly adhesive polyarylene ether - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyarylene ether improved in adhesion to an LSI substrate without detriment to dielectric properties, film formability, heat resistance, and low hygroscopicity inherent in a polyarylene ether by (co)polymerizing one or more phenolic monomers. SOLUTION: One or more phenolic monomers are (co)polymerized to obtain a polyarylene ether containing 10-80 wt.%, desirably, 20-60 wt.%, more desirably, 30-50 wt.%, based on the total polymer, component having a molecular weight of 1,000-50,000 (in terms of the polystyrene as determined by gel permeation chromatography) and comprising 50-98 wt.% 2,6-diphenylphenol repeating units of the formula and 2-50 wt.% phenolic comonomer units. A polymer solution obtained by dissolving 2-70 wt.%, desirably, 5-30 wt.% this polyarylene ether in a solvent is applied to a porous support, and the wet film is cured by heating to obtain a polyarylene ether film having a thickness of 0.1-500 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating film used for a semiconductor device having a multilayer wiring structure.

[0002]

2. Description of the Related Art Conventionally, an insulating film existing between a first wiring conductor layer and a second wiring conductor layer of a multilayer wiring structure most commonly used is a chemical vapor deposition (CVD) method or the like. Is used. However, as semiconductor devices have become denser and more highly integrated, wiring has become finer and more multilayered. In multilayer wiring structures formed by conventional methods, signal delay and crosstalk in wiring layers have become problems. I have. This is a problem due in part to the high relative dielectric constant of the silicon dioxide film. In order to reduce the dielectric constant, doping with fluorine is also performed. However, there is a limit in reducing the dielectric constant due to a trade-off relationship with thermal stability.

[0003] Polymers used for electric and electronic parts are generally required to have high heat resistance, low dielectric constant, low water absorption, and high adhesion to other base materials. For example, phenol resins, epoxy resins, polyimide resins, fluorine resins, bismaleimide resins, polyphenylene ether resins, and the like are used. However, phenol resins and epoxy resins have low heat resistance and high dielectric constant. Polyimide-based resins have high heat resistance, but have the disadvantage that they have strong polarities and therefore have high water absorption and high dielectric constant. Fluorine-based resins have extremely low dielectric constant and water absorption, but have the disadvantage of low adhesion to other substrates. In recent years, bismaleimide-based resins and polyphenylene ether-based resins have been reported particularly as insulators for wiring boards. These resins have a low dielectric constant but are inferior in heat resistance.

As a polyphenylene ether resin, poly-2,6-dimethylphenol has been industrialized and used as an engineering plastic in various fields, and a printed circuit board material based on this resin has been proposed. This resin has a low dielectric constant and low water absorption, and is useful as a material for electric and electronic components.
Heat resistance is not enough compared to polyimide and the like.
It is considered that the reason why poly-2,6-dimethylphenol is inferior in heat resistance is that a methyl group in a side chain is easily desorbed by heating, and therefore, a polyphenylene ether resin having higher heat resistance, that is, polyarylene. Poly-2,6-diphenylphenol was studied as an ether-based resin. The polymer has a glass transition temperature of 230
It is known that it has excellent heat resistance, such as a melting point of 480 ° C. and a thermal decomposition onset temperature of 515 ° C., and has a high potential as a material for electric and electronic parts [macr
omolecules 4,5,643 (197
1)]. However, this polymer is crystalline, and crystallization proceeds when heated. Therefore, for example, poly-2,6
-When a film used as an insulating layer of a wiring board is formed using diphenylphenol, the film may be peeled off or deformed due to heating during film formation or heat generated during use of a wiring board using this film as an insulating layer. However, disadvantages such as cracking of the film may occur. Also, in this case, even if the above-described phenomena such as peeling, deformation, and cracking do not occur, disadvantages such as the film shrinking due to heat generated during the use of the wiring board and the wiring being cut due to the stress generated thereby. May occur. Therefore, in order to put this polymer to practical use, it must be made amorphous.

[0005] A typical method for amorphizing a crystalline polymer is to disrupt the regularity of the structure by copolymerization or chemical modification. As for poly-2,6-diphenylphenol, A.I. S. Hay et al. Are Journal of Polym
er Sci, Part A, vol 31, 2015
(1993) and the like having a substituent on the side chain benzene ring.
It discloses that it can be made amorphous by copolymerizing with 6-diphenylphenol. However, these comonomers require several steps in their synthesis and are difficult to commercialize industrially.Moreover, many comonomers contain an aliphatic group or a fluorine atom, so that The required characteristics such as heat resistance and adhesion to other base materials were reduced.

[0006] When fabricating a semiconductor device having a multi-layer wiring structure, it is general that temperature cycles are required many times. In addition to heat resistance when subjected to temperature cycling as an insulating material, adhesion to other base materials is extremely important, and adhesion is poor, and phenomena such as film peeling must not occur. In order to improve adhesion, an adhesive aid is generally used, but the use of an adhesive aid makes the process complicated.
In some cases, the cost is increased, and problems may occur in the heat resistance and dielectric properties of the bonding aid itself. Polyarylene ether resins developed as materials for electrical and electronic components
For example, it is described in JP-A-9-202823. This polymer is a wholly aromatic polyether containing no fluorine, and is a material having both high heat resistance, low dielectric constant, and low water absorption, but an adhesion promoter can also be used for adhesion to an LSI substrate. It is not mentioned at all.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an insulating film having the above-mentioned requirements, that is, having heat resistance, non-crystallinity and high adhesion.

[0008]

Means for Solving the Problems The present inventors diligently studied the conditions under which polyarylene ether exhibits high adhesion to an LSI substrate without impairing the dielectric properties, thin film forming properties, heat resistance and low water absorption. As a result, they have found that this object can be achieved by controlling the molecular weight component of the polyarylene ether, and have completed the present invention.

That is, the present invention provides (1) a polyarene ether comprising a component having a molecular weight of 1,000 to 50,000 in a total polymer of 10 to 80% by weight, and (2) a polyarylene ether. 2. The polyarylene ether aromatic copolymer chain according to claim 1, wherein the aromatic copolymer chain comprises a plurality of the following aromatic copolymer chains.

Embedded image And (B) a phenolic comonomer unit inserted in a repetition of the 2,6-diphenylphenol unit represented by the following formula (3): 2 to 0.1 to 50 formed from the polyarylene ether according to any one of
A polymer film having a thickness of 0 μm.

Hereinafter, the present invention will be described in detail. In the present invention, a component having a molecular weight in terms of polystyrene of not less than 1000 and not more than 50,000 in gel permeation chromatography (GPC) is preferably not less than 10% by weight and not more than 80% by weight, more preferably not less than 20% by weight and not more than 60% by weight in the whole polymer. Is a polyarylene ether containing not less than 30% by weight and not more than 50% by weight. The polyarylene ether containing 10 to 80% by weight of a component having a molecular weight of 1,000 or more and 50,000 or less has a remarkable improvement in adhesion to a Si wafer for LSI as compared with a polyarylene ether not containing it.

If the component having a molecular weight of 1,000 or more and 50,000 or less is less than 10% by weight, the adhesion to the Si wafer for LSI is remarkably reduced. 1000 or more and 50,000
Adhesion of a polyarylene ether containing a component having the following molecular weight in excess of 80% by weight to a Si wafer for LSI is better, but the mechanical strength of the polymer may be reduced. A component having a molecular weight of less than 1000 is effective for improving the adhesion, but may cause a decrease in mechanical strength, heat resistance and the like. On the other hand, components having a molecular weight of more than 50,000 are not very effective in improving adhesion.

In order to obtain a polyarylene ether containing 10 to 80% by weight of a component having a molecular weight of 1,000 to 50,000, a polymerization reaction of the polyarylene ether is carried out.
The reaction time may be controlled while tracking the molecular weight by GPC, and various molecular weight components may be isolated in advance and easily obtained by appropriately mixing them. The molecular weight of all polyarylene ethers is usually from 1,000 to 3,000,000. More preferably, it is from 1,000 to 200,000.

In order to improve the adhesion between the Si wafer for LSI and the insulating film, an adhesion aid is generally used.
The polyarene ether of the present invention can also be used depending on the situation. Examples of the adhesion aid include trimethylchlorosilane, γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinyltris (β-
(Methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- Examples thereof include (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -β-aminopropylmethyldimethoxysilane, and hexamethyldisilazane.

The polyarylene ether used in the present invention is a polymer obtained from one or more phenolic monomers. Examples of the phenolic monomer include 2-phenylphenol, 3-phenylphenol, 4-phenylphenol, 2,6-diphenylphenol, 2,3-diphenylphenol,
4-diphenylphenol, phenol, α-naphthol, β-naphthol and the like. These may be polymerized alone or, if necessary, in combination. Also, a phenol containing a small amount of an aliphatic group, for example, 2,6-, within a range not to impair the gist of the present invention.
Copolymerization of dimethylphenol, o-cresol, or the like may be used. Copolymerized polyarylene ethers are disclosed in JP-A-9-202823 and WO97 / 015.
94.

Further, various kinds of polyarylene ethers can be used as a mixture. If the polyarylene ether is an aromatic copolymer comprising a plurality of the following aromatic copolymer chains, in addition to low dielectric constant, heat resistance, it is easy to control the molecular weight at the time of polymerization, and can be industrially manufactured at low cost. It is preferable because it is excellent in that it is easy to purify and contains a small amount of impurities such as Na which is very important for semiconductor use. Each aromatic copolymer chain is composed of (A) a 2,6-diphenylphenol repeating unit represented by the above formula (1), and (B) a phenolic compound inserted into the 2,6-diphenylphenol repeating unit. An aromatic copolymer containing comonomer units.

In the present invention, the phenolic comonomer unit (B) is (i) a monosubstituted phenol having one substituent selected from the group consisting of a monovalent aromatic group having 6 to 18 carbon atoms and a halogen atom. A derived comonomer unit,
(Ii) a comonomer unit derived from α-naphthol,
(Iii) a comonomer unit derived from β-naphthol; and (iv) an alkyl group having 1 to 10 carbon atoms, 1 to 1 carbon atoms.
0 selected from the group consisting of comonomer units derived from phenol substituted with at least one aliphatic group selected from the group consisting of an alkoxyl group having 0, an alkenyl group having 2 to 10 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms. At least one phenolic comonomer unit.

Specific examples of the monosubstituted phenol that can be used as the above comonomer unit (i) include 2-
Examples include phenylphenol, 3-phenylphenol, 4-phenylphenol, naphthylphenol, biphenylphenol, fluorophenol and chlorophenol. Particularly preferred comonomer units (i) in the present invention are those derived from 2-phenylphenol.

Examples of the phenol substituted with at least one aliphatic group which can be used as the above comonomer unit (iv) include 2,6-dimethylphenol and cresol. The aromatic copolymer of the present invention does not necessarily contain the comonomer unit (iv), and does not contain the comonomer unit (iv) when the copolymer of the present invention is required to have particularly high heat resistance. Is preferred. When the aromatic copolymer of the present invention contains a comonomer unit (iv), its amount must be 20% by weight or less, preferably 10% by weight, based on the amount of the phenolic comonomer unit (B). % By weight or less. When the amount of the comonomer unit (iv) exceeds 20% by weight, there is a disadvantage that the thermal decomposition temperature of the aromatic copolymer decreases. In the present invention, each of the phenolic comonomer units (B) is preferably a comonomer unit derived from 2-phenylphenol.

In the 2,6-diphenylphenol copolymer of the present invention, the amount of the 2,6-diphenylphenol repeating unit (A) is from 50 to 98 based on the weight of the 2,6-diphenylphenol copolymer. %, And the amount of the phenolic comonomer unit (B) is 2 to 50% by weight based on the weight of the 2,6-diphenylphenol copolymer. [However, as described above, the amount of the comonomer unit (iv) is 20% by weight or less based on the weight of the phenolic comonomer unit (B). The above 2,6-
The content of the diphenylphenol repeating unit (A) is
Preferably it is 60 to 95% by weight, more preferably 70 to 90% by weight. When the content of the 2,6-diphenylphenol repeating unit (A) is less than 50% by weight, heat resistance is not sufficient, and when it is more than 98% by weight, it does not become sufficiently amorphous.

The polyarylene ether of the present invention can be molded by various molding methods used for molding ordinary polymers. Structural parts by injection molding, extrusion molding, etc.
Although it can be formed into a film or the like, the polyarylene ether of the present invention is dissolved in an appropriate solvent to form a polymer solution, and then formed into a film by a known method such as a casting method, a casting method, or a spin coating method. By doing so, the film thickness can be advantageously used as an insulating film or the like for electric or electronic parts.
A 500 μm polyarylene ether film can be obtained. Also, a glass cloth, a suitable porous support such as a nonwoven fabric is impregnated with the polymer solution to form a prepreg,
A plate formed by heating and curing can also be used as a substrate for a wiring board.

The solution of the polyarylene ether of the present invention will be described below. The solvent is not particularly limited as long as it dissolves the polyarylene ether of the present invention, but includes aromatic hydrocarbons such as toluene, xylene, mesitylene, durene, and tetralin; chloroform, dichloromethane, dichloroethane, trichloroethane, tetrachloroethane, and chlorobenzene. , Dichlorobenzene, etc .; ketones, such as cyclohexanone, cyclopentanone, acetophenone; esters, such as ethyl lactate; ethers, such as tetrahydrofuran, dioxane, anisole; N-methylpyrrolidone; tetramethylurea; Glycol-1-monomethyl ether-2-acetate; 1
-Methoxy-2-propanol. Among them, preferred in consideration of workability, safety, economy, film forming property, and the like are toluene, xylene, mesitylene, cyclohexanone, cyclopentanone, anisole, N-methylpyrrolidone, ethyl lactate,
Propylene glycol-1-monomethyl ether-2-
Acetate. These solvents may be used alone, but several kinds of solvents may be mixed and used in order to improve film forming property, wettability to a substrate, workability, and the like.

The appropriate concentration of the polyarylene ether solution varies depending on the purpose of use, the molecular weight of the polymer, and the like.
A range of -70% by weight, preferably 5-30% by weight is used. After the obtained polymer solution is formed into a film by the method described above, the solvent is evaporated to obtain a polymer film. This polymer film is not only excellent in heat resistance, water resistance and adhesiveness as it is, but also has excellent electrical properties such as low dielectric constant and dielectric loss and high dielectric breakdown voltage. However, heat treatment, solvent resistance, adhesion and the like are further improved by subjecting to a crosslinking treatment, and a polymer film having more excellent properties can be obtained. Crosslinking can be performed by a known method such as heat treatment, light irradiation, or electron beam irradiation. Since the manufacturing process of electric and electronic devices often includes a heat treatment step, it is the simplest to crosslink a polyarylene film by heat treatment when manufacturing an electric or electronic device using the polymer film of the present invention. preferable. Crosslinking by heating proceeds only by heating the polyarylene film of the present invention at an appropriate temperature, but by using a solution obtained by adding a radical generator to the polyarylene solution, the crosslinking density is effectively increased. A crosslinked polyarylene ether film can be obtained.

As the radical generator in the present invention, those generally known as a radical generator can be used. For example, peroxides such as benzoyl peroxide, dicumyl peroxide, t-butylperoxyisobutyrate, di-t-butylperoxy-2-methylcyclohexane, 1,1-bis (t-butylperoxy) 3,3,5-trimethyl Cyclohexane, 1,1-
Bis (t-butylperoxy) cyclohexane, 2,2
-Bis (4,4-di-t-butylperoxycyclohexyl) propane, 1,1-bis (t-butylperoxy) cyclododecane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy -3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,
5-dimethyl-2,5-di (m-toluylperoxy)
Hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate,
2,2-bis (t-butylperoxy) butane, t-butylperoxybenzoate, n-butyl-4,4-bis (t-butylperoxo) valerate, di-t-butylperoxyisophthalate, α, α′- Bis (t-butylperoxy) diisopropylbenzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butyl peroxide, p-menthanehydroperoxide, 2,5-dimethyl-2,5- Di (t-butylperoxy) -3-hexyne, diisopropylbenzene hydroperoxide, t-butyltrimethylsilyl peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumyl hydroperoxide, t-hexyl hydroperoxide, t- Butyl hydroperoxide, t-butyl cumylpe Oxide, p- summation hydroperoxide, diacetyl peroxide, diisobutyryl peroxide, dioctanoyl peroxide, didecanoyl peroxide, dilauroyl peroxide, m
-Toluyl peroxide, t-butylperoxylaurate, 1,3-bis (t-butylperoxyisopropyl) benzene.

Further, a bibenzyl compound represented by the following formula (2) can be preferably used as a radical generator.

Embedded image (R in the formulas each independently represents a hydrogen atom and a carbon number of 1 to 1.
20 hydrocarbon groups, cyano group, nitro group, carbon number 1-2
Represents an alkoxyl group of 0 or a halogen atom. )

Specific examples of the bibenzyl compound represented by the above formula (2) include 2,3-dimethyl-2,3-diphenylbutane, α, α′-dimethoxy-α, α′-diphenylbibenzyl, and α, α ′ -Diphenyl-α-methoxybibenzyl, α, α′-dimethoxy-α, α′dimethylbibenzyl, α, α′-dimethoxybibenzyl, 3,4-dimethyl-3,4-diphenyl-n-hexane, , 2,
Nitrile 3,3-tetraphenylsuccinate, dibenzyl and the like can be mentioned.

The decomposition temperature of the radical generator of the present invention is preferably higher. When a radical generator having a low decomposition temperature is used, not only the pot life is shortened, but also the radical generator is rapidly decomposed when the solvent is dried, so that crosslinking is not effectively generated and the film quality is deteriorated. Although it is not clear why a radical generator that decomposes at a high temperature gives a film with superior properties, it is not clear, but since many of the polymers of the present invention have a high glass transition temperature of 200 ° C. or higher, the motion of the polymer chain It is considered that even if radicals are generated at a low temperature where the properties are poor, they are deactivated before a crosslinking reaction is caused. Preferably 1
The half-life temperature per minute is 150 ° C. or higher, more preferably 2
A radical generator at a temperature of 00 ° C. or higher is used.

The amount of the radical generator to be added is preferably from 0.1 to 200% by weight, more preferably from 1 to 50% by weight, most preferably from 5 to 30% by weight, based on the polymer. If the amount is too small, the effect of addition cannot be seen. Regarding the method of adding the radical generator, it is most convenient to dissolve it in a solvent together with the polymer when preparing the polymer solution. At this time, additives for improving workability and film characteristics, such as an adhesion improver and a leveling agent, can also be added. In general, in electric and electronic materials, it is necessary to avoid mixing of so-called particles as much as possible, and the polymer obtained by the above method,
Alternatively, it is preferable that the solution of the polymer and the radical generator be filtered through a filter of about 0.1 μm to 1 μm before use.

In order to obtain an interlayer insulating film, a passivation film and the like of an LSI multilayer wiring using the polymer solution of the present invention, a spin coating method is generally applied. At this time, the substrate is often subjected to a surface treatment in order to improve wettability, adhesion, and the like. A film of usually 0.1 to 10 μm can be obtained by one spin coating. Of course, when it is desired to increase the film thickness, the polymer concentration in the solution may be increased, or spin coating may be repeated after heat curing. The drying temperature of the obtained film varies depending on the type of the solvent, but is generally from room temperature to 200 ° C. Evaporation too rapidly deteriorates the smoothness of the film surface. In order to control the evaporation rate of the solvent, a method such as heating and drying in two stages is also preferable. For example, when toluene is used as the solvent, a method of preliminarily drying at 40 to 80 ° C. or lower than the boiling point of toluene and then completely volatilizing the toluene at about 180 ° C. or higher than the boiling point of toluene can be used. .

In the case where the film obtained as described above is crosslinked, a treatment such as heating is performed thereafter. When performing thermal crosslinking, the heating temperature is usually 200 ° C. or higher, preferably 3 ° C.
The temperature is at least 00 ° C, more preferably at least 350 ° C. 2
When the temperature is lower than 00 ° C., the crosslinking reaction does not substantially proceed even if the radical generator is added. An example of the crosslinking condition is a temperature of 350 to 450 ° C. in a nitrogen atmosphere for about 1 minute to 3 hours.
The presence of oxygen in the heating atmosphere increases the rate of the crosslinking reaction. For example, the crosslinked polymer film of the present invention is used as a buffer film of a semiconductor element using aluminum as a wiring material or an insulating film of a wiring structure used for a semiconductor element. In the case where is used, when heating is performed in the presence of oxygen, aluminum as a wiring material is oxidized. When heating in the presence of oxygen is not preferable, crosslinking proceeds at a practically no problem rate even in an inert atmosphere such as a nitrogen, helium, or argon atmosphere.

The polymer before cross-linking is soluble in a general organic solvent, but in a sufficiently cross-linked polymer, it hardly dissolves or swells in the solvent. In addition, the adhesion to an LSI Si wafer or the like is remarkably improved. It is easy to pattern this film using a normal resist if necessary. Further, by appropriately setting the molecular weight and the concentration, the material is excellent in impregnation into a porous support and embedding into a fine wiring pattern. Further, it is extremely excellent in adhesion to wiring materials such as aluminum and copper, and ceramic materials such as glass and silica. The crosslinked thin film obtained in this way has extremely excellent heat resistance,
It has electrical properties, mechanical properties, low water absorption and high adhesion.
It can be advantageously used as an electric or electronic material such as an interlayer insulating film of an SI multilayer wiring, an LSI passivation film, a printed circuit board, a substrate material such as a BGA or an MCM.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited by these. The weight average molecular weight of the polyarylene ether is TSKgel-G500 manufactured by TOSOH.
0H, Showa Denko GPC K-801 and Showa Denko GPC K-803 columns were connected in series, and chloroform was used as a developing solvent (flow rate 1 ml / m 2
in), and measured by gel permeation chromatography (GPC) using a GPC device manufactured by JASCO Corporation, and determined in terms of polystyrene. The differential thermal analysis (DSC) was performed at a rate of 10 ° C./min in nitrogen using a DSC7 differential thermal analyzer manufactured by PerkinElmer.

Heat resistance is THERM manufactured by Rigaku Denki Co., Ltd.
Measured in helium using an OFLEX Tas-300 TG8110D thermobalance. The evaluation was based on the isothermal thermal weight loss and 5% weight loss of the polyarylene film.
The isothermal thermal weight loss was evaluated by measuring the weight loss when the temperature was raised to 400 ° C at a heating rate of 50 ° C / min and maintained at 400 ° C for 2 hours. 5% weight loss at 50 ° C
The temperature was raised to 400 ° C. at a heating rate of / min and maintained for 1 hour, and then the temperature was raised again to 900 ° C. at a heating rate of 10 ° C./min. The film thickness of the polyarylene film is measured using a contact-type film thickness meter (DE manufactured by Sloan).
KTAKII). The adhesion test is a stud pull test (Sebastian F manufactured by Quad)
ive).

[0033]

Example 1 (Polyarylene ether) 350 g of toluene was weighed into a 500 ml separable flask equipped with an oxygen introducing tube and a stirrer, and 30 g (121.8 mmol) of 2,6 was added.
-Diphenylphenol and 5.18 g (30.43 mm
ol) 2-phenylphenol was added and stirred under a nitrogen stream to dissolve. 0.5g cuprous bromide, N, N,
N ', N'-tetramethylethylenediamine 400 μl
And 8.72 g of anhydrous magnesium sulfate were added, and oxidative coupling polymerization was carried out at normal pressure and at 60 ° C. for about 5 hours while introducing oxygen from below the liquid surface. After completion of the reaction, the insolubles in the reaction solution were filtered with a PTFE 0.5 μm filter, reprecipitated with methanol, and the polymer solid was isolated and dried in vacuo. The yield after drying was 34 g (98% yield), and a solvent-soluble copolymer was obtained quantitatively. The weight average molecular weight in terms of polystyrene is about 130,000,
It had a molecular weight distribution of 700,000. Also 1000
The molecular weight component of ５０50,000 was 35% by weight in the total polymer. 34 g of the obtained crude polymer was placed in a flask with acetic acid 2
After dissolving in 300 ml of THF containing 0 ml and heating under reflux for about 1 hour, it was dropped into MeOH and reprecipitated to collect a solid content. When the residual copper content of the obtained solid was measured by ICP, a residual of 0.8 ppm was recognized. For further purification, 34 g of the obtained polymer was dissolved in 340 ml of THF, passed through a cation exchange resin PK220 manufactured by Mitsubishi Chemical Corporation, and then dropped into MeOH for reprecipitation purification. When the residual copper content of the obtained solid was measured by ICP, it was 0.1 p.
pm or less. In addition, this polymer was
As a result, the crystallization peak at 240 ° C. and the melting peak of the polymer at around 480 ° C., which are observed when the homopolymer of 2,6-diphenylphenol was analyzed by DSC, were not observed. In addition, a peak derived from the glass transition point was observed. This indicates that the obtained polymer is an amorphous copolymer, whereby the obtained polymer is a copolymer of 2,6-diphenylphenol and 2-phenylphenol. Was confirmed. The 5% weight loss temperature of the obtained polymer was 540 ° C.
When maintained at 0 ° C. for 2 hours, the weight loss per hour was 1.2%.

(Crosslinked film) Polymer 1 obtained by the above method
0 g and 2 g of 2,3-dimethyl-2,3-diphenylbutane as a crosslinking agent were dissolved in 38 g of anisole, cast on a glass plate, and dried to obtain a film having a thickness of 80 μm.
The coating was annealed at 450 ° C. for 1 hour in nitrogen. The annealed film was analyzed by DSC, and no glass transition was observed at a temperature of 500 ° C. or less. The annealed film was immersed in N-methylpyrrolidone, but there was no change in appearance, and the amount of elution calculated from the weight loss before and after immersion (uncrosslinked polymer content of the film) was only 0.2%. . Furthermore, the 5% weight loss temperature of the annealed coating is 55
At 3 ° C., and the weight loss per hour when maintained at 400 ° C. for 2 hours was 0.8%, the use of this crosslinking agent improved the heat resistance and solvent resistance of the coating. It was confirmed.

(Adhesion of crosslinked film) 10 g of the polymer obtained by the above-mentioned method and 2 g of 2,3-dimethyl-2,3-diphenylbutane were dissolved in 39 g of anisole, and the resulting solution was placed on a silicon substrate at 1500 rpm. , And then dried and cured at 450 ° C. for 1 hour in nitrogen to form a coating having a thickness of 1.0 μm. The obtained thin film did not show any defects such as cracks at all by visual observation and observation with an optical microscope. When this film was immersed in N-methylpyrrolidone, there was no change in appearance and no change in film thickness after drying. Further, the adhesion between the silicon substrate and the crosslinked film by the stud pull test was good.

Example 2 A polymer was produced in exactly the same manner as in Example 1 except that the oxidative coupling reaction time was changed to 5.5 hours, and the adhesion was measured by the same operation. (Example 3) A polymer was produced in exactly the same manner as in Example 1 except that the oxidative coupling reaction time was changed to 4.5 hours.
The adhesion was measured by the same operation. (Example 4) A polymer was produced in exactly the same manner as in Example 1 except that the oxidative coupling reaction time was changed to 4.0 hours.
The adhesion was measured by the same operation.

Comparative Example 1 (Polyarylene ether) 180 g of toluene was obtained by adding 10 g of the polymer obtained in Example 1 (polyarylene ether).
And the solution is stirred with 40 g of ethanol.
Was gradually added. After collecting the supernatant by decantation, the precipitate was washed three times with 100 g of ethanol and dried to obtain a solid content (11.1 g, 55.5%).
The weight average molecular weight of this solid in terms of polystyrene was about 180,000, and had a molecular weight distribution of 5,000 to 17,000,000. Moreover, molecular weight 1000-50,000
Was 5% by weight of the total polymer.

(Adhesion of crosslinked film) A film having a thickness of 1.4 µm was obtained in the same manner as in Example 1 (adhesion of crosslinked film) except that the solid content obtained by the above-mentioned production method was used. The obtained thin film did not show any defects such as cracks at all by visual observation and observation with an optical microscope. When this film was immersed in N-methylpyrrolidone, there was no change in appearance and no change in film thickness after drying. The adhesion between the crosslinked film and the silicon substrate was measured by a stud pull test.

Comparative Example 2 A polymer was produced in exactly the same manner as in Example 1 except that the oxidative coupling reaction time was changed to 3.5 hours, and the adhesion was measured by the same operation. Table 1 below
The stud pull indicates the weight average molecular weight of each polymer in Examples 1-4 and Comparative Examples 1-2, the content of low molecular weight components of 1000-50,000 (wt%), and the adhesion between the crosslinked coating and the silicon substrate. The results evaluated by the test and the relative evaluation of mechanical strength are shown. Regarding adhesion,
The adhesive strength evaluated in Example 1 was set to 1 for convenience, and the relative strength to this was also shown.

[0040]

[Table 1] As is evident from Table 1, those having a low molecular weight component of 10 to 80% by weight clearly have excellent adhesion to the Si wafer.

[0041]

The insulating film obtained from the molecular weight composition of the present invention has a low dielectric constant, a high heat resistance, and an excellent adhesion, so that it can solve problems such as signal propagation delay and crosstalk of semiconductor devices. In addition to being effective, it has a feature that the process can be simplified, which is very useful in industry.

Claims (3)

[Claims] 1. A polyarylene ether containing a component having a molecular weight of 1,000 or more and 50,000 or less in an amount of 10 to 80% by weight based on the whole polymer. 2. The polyarylene ether aromatic copolymer chain according to claim 1, wherein the polyarylene ether is an aromatic copolymer comprising a plurality of the following aromatic copolymer chains. The following formula (1): And (B) a phenolic comonomer unit inserted in the repetition of the 2,6-diphenylphenol unit. 3. A polymer film formed from the polyarylene ether according to claim 1 and having a film thickness of 0.1 to 500 μm.