JP2002069187A - Interlayer insulating film for multilayer wiring and method of producing resin used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interlayer insulating film for multilayer wiring on a semiconductor having excellent heat resistance, water pickup, electric characteristic and storage stability of varnish, and to provide a method of producing the resin for the film. SOLUTION: The method of producing a polyhydroxy amide resin having a structure expressed by formula (1) comprises the steps of reacting bisaminophenol with a dicarboxylic acid diester obtained by purifying a reaction product of a dicarboxylic acid and a compound selected from the group of compounds expressed by formula (2), and end-capping the amine terminal of the reaction product. The interlayer insulating film for multilayer wiring comprises polybenzoxazole resin which is obtained by heating the polyhydroxy amide resin to cause dehydration and ring-closing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor interlayer insulating film made of polybenzoxazole resin and a method for producing a resin used therefor.

[0002]

2. Description of the Related Art As an interlayer insulating film material, an inorganic insulating film material using silicon dioxide formed by a chemical vapor deposition method or the like has been studied. However, a material having a high dielectric constant and high flatness is required. The performance is not sufficient as an interlayer insulating film having a multilayer wiring structure.

On the other hand, an organic insulating film has high flatness and a low dielectric constant, and polyimide resin is actively studied as a material for the organic insulating film. It was not a good performance. Polybenzoxazole resins have also been studied in the same manner, but the production method includes an acid for dehydrating and ring-closing a polyhydroxyamide resin obtained from dicarboxylic acid dichloride and a bis (aminophenol) compound by heat treatment. There is a chloride method, but chloride ions generated during the synthesis are not preferable for use in electronic materials. Dichlorohexylcarbodiimide (hereinafter abbreviated as DCC) is used as a material that does not have a possibility that the chlorine ion is mixed as an impurity,
There is a DCC method for obtaining a polyhydroxyamide resin directly from a dicarboxylic acid and a bis (aminophenol) compound, but a low-reactivity such as 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane is available. When a raw material is used, the molecular weight of the obtained polyhydroxyamide resin becomes low, and sufficient heat resistance cannot be obtained.

In addition, when a highly reactive raw material is used, the molecular weight increases, and the obtained fluorine-containing polyhydroxyamide resin is subjected to heat dehydration ring closure to obtain a fluorine-containing polybenzoxazole having excellent water resistance, water absorption, and electric properties. Resin is produced, but the varnish in which the synthesized resin is dissolved in an organic solvent is-
Although the storage stability at a low temperature such as 25 ° C. to −15 ° C. is good, there is a problem that a precipitate is generated in a few days at room temperature.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluorine-containing polyhydroxyamide resin which solves the above-mentioned problems of the prior art and is excellent in heat resistance, water absorption and electric characteristics as well as storage stability of a varnish. It is an object of the present invention to provide a method and an interlayer insulating film for a semiconductor multilayer wiring using the resin.

[0006]

The inventors of the present invention have made intensive studies to solve such problems, and as a result, the polyhydroxyamide resin obtained by the production method of the present invention has been found to be a varnish at room temperature. It has been found that the storage stability is good, and that the interlayer insulating film for semiconductor multilayer wiring using the same is excellent in water resistance, water absorption and electrical properties, and has completed the present invention.

That is, the present invention is to purify a product obtained by reacting one kind of the compounds represented by the formula (2) with a dicarboxylic acid represented by R of the formula (4). Is reacted with a bisaminophenol compound represented by R ′ of the formula (4), and the amine end of the obtained polyhydroxyamide resin is reacted with a compound group represented by the formula (7). A method for producing a polyhydroxyamide resin having a structure represented by the formula (1) obtained by end-capping with one kind of dicarboxylic anhydride selected from

[0008]

Embedded image In the formula (1), A represents a structure selected from the formula (8). m
Represents an integer of 10 to 500.

[0009]

Embedded image

[0010]

Embedded image

[0011]

Embedded image In the formula (4), X and Y indicate a structure selected from the formula (5).

[0012]

Embedded image In the formula (5), Z represents a structure selected from the formula (6), and the hydrogen atom on the benzene ring in these structures is a methyl group,
It may be substituted with at least one group selected from the group consisting of ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, fluorine atom, and trifluoromethyl group.

[0013]

Embedded image

[0014]

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Further, using a polyhydroxyamide resin having a structure represented by the formula (1) obtained by the above-mentioned production method, a polybenzo having a structure represented by the formula (3) obtained by a heat-dehydration ring closure production method. An interlayer insulating film for a semiconductor multilayer wiring, comprising an oxazole resin.

[0016]

Embedded image In the formula (3), A represents a structure selected from the formula (8). n
Represents an integer of 10 to 500.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The polyhydroxyamide resin of the present invention is produced by reacting a diamine component with a dicarboxylic acid component, and the diamine component is a bisamino compound represented by R ′ in the above formula (4). Phenolic compounds, for example,
2,4-diaminoresorcinol, 2,2-bis (3-
Amino-4-hydroxyphenyl) propane, 1,4-
Bis (3-amino-4-hydroxyphenyl) tetrafluorobenzene, 3,3′-diamino-4,4′-dihydroxybiphenyl, 3,3′-diamino-5,5 ′,
6,6′-tetrafluoro-4,4′-dihydroxybiphenyl, 2,2-bis (3-amino-4-hydroxy-5-trifluoromethylphenyl) -1,3-hexafluoropropane, 2,2- Bis (4-amino-3-hydroxy-5-trifluoromethylphenyl) -1,3
-Hexafluoropropane, 2,2-bis (3-amino-4-hydroxy-5-pentafluoroethylphenyl) -1,3-hexafluoropropane, 2- (3-amino-4-hydroxy-5-trifluoro Methylphenyl) -2- (3-amino-4-hydroxy-5-pentafluoroethylphenyl) -1,3-hexafluoropropane, and the like, but are not necessarily limited thereto.

The dicarboxylic acid component is obtained by reacting a dicarboxylic acid represented by R in the above formula (4) with one compound selected from the group of compounds represented by the above formula (2). A dicarboxylic diester is used.

The dicarboxylic acid represented by R in the above formula (4) includes, for example, 5-fluoroisophthalic acid, 2-fluoroisophthalic acid, 3-fluorophthalic acid, 4-fluorophthalic acid, 2-fluoroterephthalic acid , 2,4
5,6-tetrafluoroisophthalic acid, 3,4,5,6
-Tetrafluorophthalic acid, 4,4'-hexafluoroisopropylidenediphenyl-1,1'-dicarboxylic acid, perfluorosuberic acid, terephthalic acid, isophthalic acid, 4,4'-oxydiphenyl-1,1'-dicarboxylic acid Examples include acids, but are not necessarily limited thereto.

Examples of the compound represented by the formula (2) include 1-hydroxybenzotriazole, 4-nitrophenol, 2-mercaptobenzoxazole and the like.

In the synthesis of the dicarboxylic diester used in the present invention, the dicarboxylic acid represented by R in the above formula (4) and a compound selected from the group of compounds represented by the above formula (2) are used.
Kinds of compounds, 1,4-dioxane, ethyl acetate,
It is dissolved in a dehydrated organic solvent such as tetrahydrofuran, dimethylformamide, N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP), and a condensing agent such as DCC is added at -10 to 5 ° C. Incubate for 24 hours.

Next, the reaction solution is filtered, the filtrate is concentrated by an evaporator, and a poor solvent such as diethyl ether, petroleum ether, hexane or the like is added, and the precipitated product is recovered by filtration, or Water is added dropwise and the precipitated product is recovered by filtration. The recovered product is mixed with isopropyl alcohol to prepare
After stirring for a minute, the product is filtered off and dried under reduced pressure to give a purified dicarboxylic acid diester. This purification step is necessary to obtain a high molecular weight polyhydroxyamide resin.

The method for producing the polyhydroxyamide resin of the present invention is as follows. The dicarboxylic acid diester and the diamine component are mixed in a dehydrated organic solvent such as tetrahydrofuran, NMP or γ-butyrolactone at 30 to 90 ° C. for 5 to 24 hours.
The reaction is carried out for a period of time.
It is effective to react under an acid acceptor such as dimethylaminopyridine (DMAP) or pyridine. After the reaction between the dicarboxylic acid diester and the diamine component is completed,
Subsequently, one kind of dicarboxylic anhydride selected from the group of compounds represented by the formula (7) is added and reacted for 2 to 5 hours to obtain a polyhydroxyamide resin having a structure represented by the formula (1). can get. The amount of the dicarboxylic anhydride to be added may be at least the equivalent of the amine terminal of the resin.

In the present invention, the polybenzoxazole resin having the structure represented by the formula (3) can be obtained by subjecting the polyhydroxyamide resin obtained by the above-mentioned production method to ring closure by heating and dehydration.

In the method of manufacturing an interlayer insulating film for a multilayer wiring according to the present invention, a polyhydroxyamide resin represented by the above formula (1) is dissolved in an organic solvent to prepare a varnish of 5 to 50% by weight. , Spin coating using a spinner, spray coating using a spray coater, dipping, printing, roll coating, etc., on a Si wafer or on a Si wafer, SiN, SiO2, SiON, Ta, Ti, C
Coating and film formation on a substrate on which u is formed. Then
Preferably, it can be manufactured by drying at 300 to 500 ° C., heating and dehydrating the polyhydroxyamide resin to form a polybenzoxazole resin insulating film.

As the organic solvent that can be used for the varnish, generally known non-aqueous organic solvents can be used. In particular,
N, N-dimethylformamide, NMP, dimethylsulfoxide, γ-butyrolactone and the like can be exemplified. If necessary, various additives such as an adhesive such as a silane coupling agent and a leveling agent such as a fluorine-based agent can be used.

The present invention is an interlayer insulating film for a semiconductor multilayer wiring, comprising a polybenzoxazole resin obtained from a polyhydroxyamide resin having excellent varnish storage stability obtained by the above-mentioned manufacturing method.

[0028]

EXAMPLES The present invention will be described below with reference to examples, but is not limited thereto.

Example 1 (1) Synthesis of dicarboxylic acid diester 39.2 g of 4,4'-hexafluoroisopropylidenediphenyl-1,1'-dicarboxylic acid and 27.0 g of 1-hydroxybenzotriazole were added to dehydrated tetrahydrofuran. It was dissolved in a mixed solvent of 400 mL of (THF) and 15 mL of dehydrated N, N-dimethylformamide (DMF), and the solution was cooled to 0 to 5 ° C. While maintaining the liquid temperature at 0 to 5 ° C, a DCC solution (41.3 g of DCC was dehydrated in TH)
F dissolved in 80 mL), and the mixture was stirred at room temperature for 24 hours. After stopping the stirring, the reaction solution was filtered, and the filtrate was concentrated by an evaporator to obtain hexane 2
00 mL was added. The precipitated product was collected by filtration, mixed with 200 mL of isopropyl alcohol (IPA), and stirred for 30 minutes. The product was separated by filtration and dried under reduced pressure to obtain 47.6 g of dicarboxylic acid diester.

(2) Synthesis of polyhydroxyamide resin 12.5 g of dicarboxylic acid diester obtained above,
7.48 g of 2,2-bis- (3-amino-4-hydroxyphenyl) hexafluoropropane, DMAP4.
89 g, γ-butyrolactone 60 mL, NMP 60 mL
Was placed in a 300 mL four-necked flask, and was stirred under a nitrogen atmosphere at a liquid temperature of 60 ° C. for 2 hours and at 80 ° C. for 8 hours. Then 5
-Norbornene-2,3-dicarboxylic anhydride 0.67
g in 20 mL of γ-butyrolactone and added dropwise.
Stirred at 0 ° C. for 3 hours and cooled to room temperature. After filtering the reaction solution, the filtrate was dropped into 1.5 L of a mixed solvent of water / IPA = 20/1 to obtain a precipitate of a polyhydroxyamide resin. After drying the resin, the molecular weight was measured by GPC (in terms of polystyrene). As a result, the weight average molecular weight was 16,000.
A 40 wt% varnish prepared by dissolving the obtained polyhydroxyamide resin in NMP and filtering was free from precipitation at room temperature for 35 days.

(3) Polybenzoxazole resin fill
Preparation and evaluation of the varnish The varnish prepared above was rotated at 80 rpm using a spinner.
10 seconds at 0 rpm, then 10 seconds at 2000 rpm
Is applied on the wafer under the conditions of
Dry in an oven at 50 ° C for 1 hour and at 350 ° C for 3 hours.
Let dry. By this drying, heat dehydration ring closure and brown toughness
A polybenzoxazole resin film was obtained. this
The resin has an infrared absorption spectrum of 1055 to 10
60cm ^-1From the CO stretching of the oxazole ring
Confirmed the work. Thermogravimetric analysis (in nitrogen, heating rate 10 ° C
/ Min) was 480.
° C. The dielectric constant of the film is 2.5 at 1 MHz.
Water absorption rate is 23 ° C / 2 according to JIS K6911.
It was 0.1% in 4 hours.

Example 2 In the synthesis of the polyhydroxyamide resin of Example 1, 5-norbornene-2,3-
Replacing 0.67 g of dicarboxylic anhydride with 0.15 g,
A polyhydroxyamide resin was synthesized and evaluated in the same manner as in Example 1 except that the reaction time at 80 ° C. after the addition of 5-norbornene-2,3-dicarboxylic anhydride was changed from 3 hours to 12 hours. . The polyhydroxyamide resin has a weight average molecular weight of 19,000 and is prepared by dissolving it in NMP.
No precipitate was observed in the t% varnish for 20 days.
When a polybenzoxazole resin film was formed under the same conditions as in Example 1, a brown tough polybenzoxazole resin film was obtained. For this resin, a peak derived from C—O stretching of the oxazole ring was confirmed at 1055 to 1060 cm ⁻¹ by infrared absorption spectrum. The thermal decomposition onset temperature was measured by thermogravimetric analysis (in nitrogen, heating rate 10 ° C./min) and found to be 480 ° C. The dielectric constant of the film is 2.5 at 1 MHz, and the water absorption
Based on K6911, it was 0.1% at 23 ° C / 24 hours.

Example 3 In the synthesis of the polyhydroxyamide resin of Example 1, 5-norbornene-2,3-
A polyhydroxyamide resin was synthesized and evaluated in the same manner as in Example 1 except that 0.67 g of the dicarboxylic anhydride was changed to 1.34 g. The weight average molecular weight of the polyhydroxyamide resin was 14,000, and no precipitate was observed for 30 days in a 40 wt% varnish prepared by dissolving in NMP. When a polybenzoxazole resin film was formed under the same conditions as in Example 1, a brown tough polybenzoxazole resin film was obtained. For this resin, a peak derived from C—O stretching of the oxazole ring was confirmed at 1055 to 1060 cm ⁻¹ by infrared absorption spectrum. The thermal decomposition onset temperature was measured by thermogravimetric analysis (in nitrogen, heating rate 10 ° C./min) and found to be 480 ° C.
The dielectric constant of the film was 2.5 at 1 MHz, and the water absorption was 0.1% at 23 ° C./24 hours according to JIS K6911.

Example 4 In the synthesis of the polyhydroxyamide resin of Example 1, 5-norbornene-2,3-
A polyhydroxyamide resin was synthesized and evaluated in the same manner as in Example 1 except that the dicarboxylic anhydride was changed to ethylene-1,2-dicarboxylic anhydride. The weight average molecular weight of the polyhydroxyamide resin was 18,000, and no precipitate was observed for 30 days in a 40 wt% varnish prepared by dissolving in NMP. When a polybenzoxazole resin film was formed under the same conditions as in Example 1, a brown tough polybenzoxazole resin film was obtained. According to the infrared absorption spectrum of this resin, 1055 to 10
A peak derived from the CO stretching of the oxazole ring at 60 cm ^-1 was confirmed. Thermogravimetric analysis (in nitrogen, heating rate 10 ° C
/ Min) was 470.
° C. The dielectric constant of the film was 2.5 at 1 MHz, and the water absorption was 23 ° C./2 according to JIS K6911.
It was 0.13% in 4 hours.

Example 5 (1) Synthesis of dicarboxylic acid diester 19.6 g of 4,4'-hexafluoroisopropylidenediphenyl-1,1'-dicarboxylic acid and 15.3 g of 4-nitrophenol were dissolved in 100 mL of dehydrated THF. Then, while maintaining the mixture at 0 to 5 ° C, a DCC solution (DCC
22.7 g was dissolved in 50 mL of dehydrated THF), and the mixture was stirred at room temperature for 24 hours. The reaction solution was filtered, the filtrate was concentrated, and 200 mL of hexane was added. The precipitated product was collected by filtration, mixed with 150 mL of IPA, and stirred for 1 hour. The product was separated by filtration and dried under reduced pressure to obtain 22.2 g of dicarboxylic acid diester.

(2) Synthesis of polyhydroxyamide resin 11.5 g of the dicarboxylic acid diester obtained above,
2,2-bis (3-amino-4-hydroxyphenyl)
7.48 g of hexafluoropropane, 4.89 of DMAP
g, 60 mL of γ-butyrolactone and 60 mL of NMP
Put in a 00 mL four-necked flask, and in a nitrogen atmosphere, liquid temperature 6
The mixture was stirred at 0 ° C for 2 hours, at 80 ° C for 8 hours, and at 90 ° C for 5 hours. Thereafter, 0.67 g of 5-norbornene-2,3-dicarboxylic anhydride was dissolved in 20 mL of γ-butyrolactone and added dropwise, followed by stirring at 80 ° C. for 3 hours and cooling to room temperature. After filtering the reaction solution, the filtrate was dropped into 1.5 L of a mixed solvent of water / IPA = 20/1 to obtain a precipitate of a polyhydroxyamide resin. After drying the resin, the molecular weight was measured by GPC (in terms of polystyrene) to find that the weight average molecular weight was 12,000. A 40 wt% varnish prepared by dissolving the obtained polyhydroxyamide resin in NMP and filtering was free from precipitation at room temperature for 35 days.

(3) Polybenzoxazole resin fill
Preparation and evaluation of the varnish The varnish prepared above was rotated at 80 rpm using a spinner.
10 seconds at 0 rpm, then 10 seconds at 2000 rpm
Is applied on the wafer under the conditions of
Dry in an oven at 50 ° C for 1 hour and at 350 ° C for 3 hours.
Let dry. By this drying, heat dehydration ring closure and brown toughness
A polybenzoxazole resin film was obtained. this
The resin has an infrared absorption spectrum of 1055 to 10
60cm ^-1From the CO stretching of the oxazole ring
Confirmed the work. Thermogravimetric analysis (in nitrogen, heating rate 10 ° C
/ Min) was 480.
° C. The dielectric constant of the film is 2.5 at 1 MHz.
Water absorption rate is 23 ° C / 2 according to JIS K6911.
It was 0.1% in 4 hours.

Comparative Example 1 In the synthesis of the polyhydroxyamide resin of Example 1, 5-norbornene-2,3-
A polyhydroxyamide resin was synthesized in the same manner as in Example 1 except that no dicarboxylic anhydride was added and the reaction at 80 ° C. after the addition of 5-norbornene-2,3-dicarboxylic anhydride was omitted. An evaluation was performed. Weight average molecular weight is 2
The 40 wt% varnish prepared by dissolving in NMP produced a precipitate within 1 day at room temperature. When a polybenzoxazole resin film was prepared under the same conditions as in Example 1,
A brown tough polybenzoxazole resin film was obtained. According to the infrared absorption spectrum of this resin, 10
Peaks derived from the C—O stretching of the oxazole ring at 55 to 1060 cm ⁻¹ were confirmed. The thermal decomposition onset temperature was measured by thermogravimetric analysis (in nitrogen, heating rate 10 ° C./min) and found to be 480 ° C. The dielectric constant of the film is 2.5 at 1 MHz, and the water absorption is based on JIS K6911.
0.1% at 23 ° C / 24 hours.

Comparative Example 2 In the synthesis of the polyhydroxyamide resin of Example 4, 5-norbornene-2,3-
A polyhydroxyamide resin was synthesized in the same manner as in Example 1 except that no dicarboxylic anhydride was added and the reaction at 80 ° C. after the addition of 5-norbornene-2,3-dicarboxylic anhydride was omitted. An evaluation was performed. Weight average molecular weight is 1
A 40 wt% varnish prepared by dissolving in 88,000 NMP produced a precipitate within 1 day at room temperature. When a polybenzoxazole resin film was formed under the same conditions as in Example 1, a brown tough polybenzoxazole resin film was obtained. According to the infrared absorption spectrum of this resin, the C—O of the oxazole ring of 1055 to 1060 cm ⁻¹ was obtained.
A peak due to stretching was confirmed. The thermal decomposition onset temperature was measured by thermogravimetric analysis (in nitrogen, heating rate 10 ° C./min) and found to be 480 ° C. The dielectric constant of the film is 1
It was 2.5 at MHz and the water absorption was 0.1% at 23 ° C./24 hours according to JIS K6911.

[0040]

The varnish prepared by dissolving a high-molecular-weight polyhydroxyamide resin synthesized by the production method of the present invention in an organic solvent has excellent storage stability and can be stored at room temperature for a long period of time. In addition, a film made of polybenzoxazole resin obtained by coating this varnish and dehydrating and ring-closing by heating has the same performance as a film made of conventional polybenzoxazole resin in terms of heat resistance, mechanical strength, and electrical properties. It has high industrial value and can be used as an interlayer insulating film for semiconductors.

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Claims (2)

[Claims] 1. A dicarboxylic acid obtained by purifying a product obtained by reacting a dicarboxylic acid represented by R of the formula (4) with one kind of a compound selected from the group of compounds represented by the formula (2). A terminal amino group of a polyhydroxyamide resin synthesized by reacting a diester with a bisaminophenol compound represented by R ′ of formula (4) is selected from the group consisting of compounds selected from the group of compounds represented by formula (7). A method for producing a polyhydroxyamide resin having a structure represented by the formula (1), which is obtained by end-capping with a dicarboxylic anhydride. Embedded image In the formula (1), A represents a structure selected from the formula (8). m
Represents an integer of 10 to 500. Embedded image Embedded image Embedded image In the formula (4), X and Y indicate a structure selected from the formula (5). Embedded image In the formula (5), Z represents a structure selected from the formula (6), and the hydrogen atom on the benzene ring in these structures is a methyl group,
It may be substituted with at least one group selected from the group consisting of ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, fluorine atom, and trifluoromethyl group. Embedded image Embedded image 2. A semiconductor comprising a polybenzoxazole resin having a structure represented by the formula (3) obtained by heating and closing a ring using the polyhydroxyamide resin obtained by the production method according to claim 1. Interlayer insulating film for multi-layer wiring. Embedded image In the formula (3), A represents a structure selected from the formula (8). n
Represents an integer of 10 to 500. Embedded image