JPH0485379A - Heat-resistant resin paste and ic using the same - Google Patents

Abstract

PURPOSE:To obtain an optimized resin paste which is thixotropic, is capable of forming uniform films with less pinholes and voids, is excellent in heat resistance, mechanical characteristics, etc., of the films, and is useful for forming protective films on the surface of IC, by incorporating a heat-resistant resin, fine particles of the heat-resistant resin and a solvent. CONSTITUTION:The title heat-resistant resin paste contains a heat resistant resin, fine particles of the heat-resistant resin and a solvent. The fine particles are present as a heterogeneous phase in contrast to the homogeneous phase made up of the heat resistant resin and the solvent prior to heat curing, and the fine particles are incorporated in the homogeneous phase of the heat- resistant resin and the solvent after heat curing. The heat-resistant resin may preferably include polyamide resins, polyamideimide resins and polyimide resins. The fine particles are made of the above resins and preferably have an average particle size of 40mum or less. Preferable solvents include lactones and carbonates.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a novel heat-resistant resin paste suitable for an overcoat material for screen printing, and an IC using the same.

(Prior Art) Usually, a resin solution itself exhibits almost no thixotropy. Thixotropy is defined as a phenomenon in which the apparent viscosity temporarily decreases due to deformation even under isothermal conditions.1 For example, under high shear speed during printing, the viscosity temporarily decreases, causing flow and transfer to the base material. This fluidity is essential for screen printing pastes, which are required to not drip or run. One method for imparting thixotropic properties to a resin solution is to disperse fine resin particles as a filler in the resin solution and form it into a paste. Various types of such pastes are known.

Examples of resin solutions used in applications that do not require high heat resistance include rosin-modified phenol resins, rosin-modified maleic resins, and melamine resins.

There are resin solutions such as epoxy resins, and for applications that require a high degree of heat resistance, resin solutions such as polyamic acid resins, which are precursors of polyimide resins, solvent-soluble polyimide resins, polyamide-imide resins, and polyamide resins are known. It is being In addition, as resin particles that are dispersed in these resin solutions to form a paste, aliphatic polyamide resin particles, melamine resin particles, epoxy resin particles, phenolic resin particles, etc. are known for applications that do not require much heat resistance. For applications requiring high heat resistance, polyimide resin particles, polyamide-imide resin particles, polyamide resin particles, etc. are known.

(Problem to be solved by the invention) Semiconductor elements, insulating films of wiring boards, W protection! Highly heat resistant for screen printing pastes used for membranes, etc.

Mechanical properties, moisture resistance and corrosion resistance are required. For such uses, a paste has been developed in which inorganic or organic fine particles are dispersed in the above-mentioned heat-resistant resin solution.

However, inorganic fine particles are themselves hard and have a high specific gravity, so they occupy a large volume in the paste, significantly impairing the mechanical properties originally possessed by the resin. If mechanical properties are not sufficient, cracks are likely to occur in the film, and inorganic particles tend to damage the surface of semiconductor elements, so insulating and protective films using pastes containing inorganic particles lack reliability.

On the other hand, organic fine particles are being studied as a material that is expected to solve the above problems, but when they are dispersed as fissures in the film, they tend to form voids at the interface between the binder resin and the particle surface, which affects the mechanical properties. .

This directly causes a decrease in moisture resistance and corrosion resistance.

This defect is more likely to occur in pastes that use inorganic fine particles that have poor affinity with resins. in this way.

With conventional pastes in which fine particles remain as fissures in the film, the fissures are uniform on average, and voids and pinholes are likely to form, regardless of whether the fissures are inorganic or organic, and high mechanical properties, moisture resistance, and corrosion resistance are required. It could not be said that it was necessarily satisfactory for the intended use. The present invention solves these problems and has thixotropic properties, can form a uniform film with especially few pinholes and voids, and has excellent heat resistance, mechanical properties, rM humidity, and corrosion resistance. The present invention provides a heat-resistant resin paste and IC1 using the same.

(Means for Solving the Problems) The present invention includes a heat-resistant resin, fine particles of the heat-resistant resin, and a solvent, and before curing by heating, the fine particles are on average uniform in a homogeneous phase consisting of the heat-resistant resin and the solvent. The present invention relates to a heat-resistant resin paste in which a heat-resistant resin, fine particles, and a solvent exist as a homogeneous phase after heat curing, and an IC using this heat-resistant resin paste.

The heat-resistant resin paste of the present invention is composed of a solution containing a heat-resistant resin and a solvent that mainly functions as a binder, and fine particles of a heat-resistant resin that mainly functions as a thixotropic agent for the paste. In this paste,
During compounding, heat-resistant resin fine particles are dispersed in a solution containing heat-resistant resin and solvent to develop thixotropic properties, and during heat curing, they dissolve in the solvent and finally form a uniform film with heat-resistant resin. . The heat-resistant resin paste in the present invention has excellent thixotropy, which directly affects printing characteristics,
The resulting film is uniform with no pinholes or voids, and has excellent mechanical properties, moisture resistance, and corrosion resistance.

As the heat-resistant resin in the present invention, either a thermosetting resin or a thermoplastic resin soluble in a solvent can be used. Examples of thermosetting resins soluble in solvents include acetylenated polyimide resins, maleimide polyimide resins, norbornene polyimide resins, and BT resin (manufactured by Mitsubishi Gas Chemical Co., Ltd.).

(Product name), Kelimide (manufactured by Lone Boulin).

Addition polymerization type polyimide resins such as (trade name), melamine resins, phenol resins, epoxy resins, etc. are used. As a thermoplastic resin that is soluble in solvents.

For example, "Plastic Handbook" (Asakura Shoten, 1
The heat-resistant resins listed in vol. 308-618 (published in 1979) are used. Heat Resistance 1 From the viewpoint of mechanical properties and solubility, preferably polyamide resin, polyamideimide resin, polyimide resin (polyamic acid resin which is a precursor of polyimide resin, tetracarboxylic dianhydride and alcohol and/or alcohol derivative) are used. The tetracarboxylic acid ester obtained by the reaction is reacted with a composition obtained by mixing or reacting a diamine, or a polyamic acid ester oligomer, or a solvent capable of forming a complex with the dianhydride and the tetracarboxylic dianhydride. A composition obtained by mixing or reacting a diamine with the obtained complex or a polyamic acid oligomer (N-methylpyrrolidone, pyridine, ε-caprolactam, etc. are preferably used as the solvent)
) are used.

Examples of polyamide resins, polyamideimide resins, and polyimide resins include polycarboxylic acids or their reactive acid derivatives and diamines (e.g., 1%
The diisocyanate obtained by reacting the diamine with phosgene or thionyl chloride can be used. Specifically, the soluble polyamide resin described in JP-A-57-64955, the soluble polyamide-imide resin described in JP-A-1-40570, and the soluble polyamide-imide resin described in JP-A-62-283154 Examples include soluble polyimide resins.

The thermal decomposition start temperature of the thermoplastic resin is preferably 250°C
As mentioned above, it is particularly preferable that the thermoplastic resin is soluble in a solvent at a temperature of 350° C. or higher, and the fine particles of the heat-resistant resin in the invention are used alone or in a mixed ratio. From the viewpoint of heat resistance and mechanical properties, it is preferable to react the above-mentioned polyamide resin, polyamideimide resin, polyimide resin (polyamic acid resin which is a precursor of polyimide resin, tetracarboxylic dianhydride and alcohol and/or alcohol derivative). A composition obtained by mixing or reacting a diamine with a tetracarboxylic acid ester obtained by reacting a polyamic acid ester oligomer, a tetracarboxylic dianhydride, and a solvent that can form a complex with this dianhydride. into a complex.

A composition mixed or reacted with a diamine or fine particles of a polyamic acid oligomer (preferably N-methylpyrrolidone, pyridine, ε-caprolactam, etc. are used as the solvent) are used.

As the heat-resistant resin fine particles, polyamide resins, polyamideimide resins, and polyimide resins having an average particle diameter of 40 μm or less are preferably used. When the paste in the present invention is used for screen printing, the thixotropic property of the paste.

Considering the uniformity of the film and the consistency with the film thickness, the fine particles of the heat-resistant resin preferably have an average particle diameter of 0.1 to 10 μm.
It is said that

Fine particles of heat-resistant resin can be obtained by non-aqueous dispersion polymerization or precipitation polymerization, but there are other methods such as mechanically crushing powder recovered from a resin solution, high shear treatment while adding a poor solvent to the resin solution, etc. Methods such as forming the resin solution into fine particles and drying the sprayed oil droplets of the resin solution to obtain fine particles are available, but any method can be used.

The thermal decomposition initiation temperature of the thermosetting and thermoplastic heat-resistant resin particles is preferably 250°C or higher, particularly preferably #'1
The glass transition temperature is preferably 350°C or higher, preferably 20°C.
The solvents used in the present invention can be used alone or in combination at temperatures above 0°C, particularly preferably above 260°C. A solvent is used.

For example, N-methylpyrrolidone, dimethylacetamide,
Dimethylformamide, 1,3-dimethyl-formula 4,5.
6-titrahydro-2(IH)-pyrimidinone, 1.3
-nitrogen-containing compounds such as dimethyl-2-imidazolidinone,
Sulfur compounds such as sulfolane and dimethyl sulfoxide, r
-butyrolactone, γ-valerolactone, r-caprolactone, r-heptalactone, α-acetyl-r-butyrolactone.

Lactones such as e-caprolactone, dioxane.

1.2-Dimethoxyethane, diethylene glycol dimethyl (or diethyl, dipropyl, dibutyl) ether, triethylene glycol dimethyl (or diethyl, dipropyl, dibutyl) ether.

Ethers such as tetraethylene glycol dimethyl (or diethyl, dipropyl, dibutyl) ether, ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, acetophenone, butanol, octyl alcohol, ethylene glycol, glycerin, diethylene glycol monomethyl (or monoethyl) ether, Alcohols such as triethylene glycol monomethyl (or hamonoethyl) ether, tetraethylene glycol monomethyl (or monoethyl) ether, phenols such as phenol, cresol, xylenol, ethyl acetate, butyl acetate, ethyl cellosolve acetate,
Esters such as butyl cellosolve acetate, toluene 1. Hydrocarbons such as xylene, diethylbenzene, and cyclohexane.

Halogenated hydrocarbons such as trichloroethane, tetrachloroethane, and monochlorobenzene are used.

The boiling point of the solvent is preferably 100° C. or higher, particularly 150° C. or higher, considering the pot life of the paste during screen printing. In addition, considering the emulsion swelling property of the plate and the moisture absorption stability of the paste, the solvent should be a non-nitrogen-containing solvent 1, for example, γ
-Butyrolactone.

Lactones such as r-valerolactone, γ-caprolactone, γ-hebutalactone, α-acetyl-r-butyrolactone, 6-caprolactone, ethylene carbonate,
Carbonates such as propylene carbonate are preferably used.

In the heat-resistant resin paste of the present invention, before heat-curing, the fine particles exist as an average of one phase in a homogeneous phase consisting of the heat-resistant resin and the solvent, and after heat-curing, the heat-resistant resin, the fine particles, and the solvent exist in a homogeneous phase. Heat-resistant resin, to exist as
It can be obtained by adjusting the composition of the heat-resistant resin particles and the solvent.

Specifically, for example, the composition shown in Table 1 using a heat-resistant resin having a repeating unit and fine particles of the heat-resistant resin represented by the following formula (1) may be mentioned.

These are examples showing embodiments of the present invention, and any composition that satisfies the properties of the heat-resistant resin paste as described above may be used. Those having the property of being compatible with each other during heat curing are preferably used. #The thermal resin is preferably one that dissolves well in the solvent at room temperature and during heat curing. Preferably, the fine particles of the heat-resistant resin are those that do not dissolve in the solvent at room temperature, but dissolve during heat curing.

The ratio of the heat-resistant resin and the heat-resistant resin fine particles is preferably such that the total amount is 100 parts by weight, and 5-70 parts by weight of the heat-resistant resin is treated with 95-30 parts by weight of the heat-resistant resin fine particles. When the proportion of fine particles of heat-resistant resin is increased, the thixotropic property and dry film thickness of the paste become E
A sample amount of 0.49. Measurement Wl: Measured at 25°C. Apparent viscosity of paste at rotation speed of 1 rpm and 1 orpm, ηl
and ηI, expressed as η1/η10.

The concentration of the heat-resistant resin and the heat-resistant resin fine particles in the paste is preferably adjusted so that the paste has a viscosity of 30 to 10,000 poise and a thixotropy coefficient of 1.5 or more. If the viscosity of the paste is less than 30 poise, the paste tends to sag after printing; if it exceeds 10,000 poise, the printing workability decreases. Particularly preferably 30
0 to 000 poise. Specifically, the concentration of the heat-resistant resin and the sum of the heat-resistant resin fine particles in the paste is:
Preferably, the Fil content is 0 to 90% by weight. 10 weight-
If it is less than 90%, the dry film thickness of the film becomes thicker and K becomes less than 90%.
If it exceeds % by weight, the fluidity of the paste will be impaired.

As a method for dispersing fine particles of heat-resistant resin in a solution containing heat-resistant resin and a solvent, roll kneading, mixer mixing, etc., which are used in the paint field, are usually used, and any method that achieves sufficient dispersion is used. There is no special limit. Most preferred is multiple crossings using three rolls.

The thixotropic coefficient of the paste in the present invention is 1.5
It is preferable to set it as above. If it is less than 1.5, the paste transferred to the substrate tends to sag, making it difficult to obtain sufficient pattern accuracy.

After the paste of the present invention is applied to a substrate, it is preferably finally baked at 150 to 500°C for 1 to 120 minutes to form a strong film.

The paste of the present invention contains an antifoaming agent if necessary.

The heat-resistant resin paste of the present invention using pigments, dyes, plasticizers, antioxidants, etc. can be used for monolithic ICs using silicon wafers as substrates, hybrid ICs using ceramic substrates or glass substrates, thermal heads, image sensors, It can be widely used for devices such as multi-chip high-density mounting boards, interlayer insulation films and/or surface protection films for various wiring boards such as flexible wiring boards and rigid wiring boards, various heat-resistant printing inks, heat-resistant adhesives, etc., and is suitable for industrial use. It is extremely useful.

Heat-resistant resin paste according to the present invention, monolithic IC
When used as a protective film for semiconductor devices such as the like, it is preferable to reduce the content of α-ray source substances such as uranium and thorium, and ionic impurities such as sodium, potassium, copper, and iron. The total content of α-ray source substances such as uranium and thorium in the protective film is preferably 1 ppb or less, and more preferably 0.2 ppb or less.
It is assumed to be less than ppb. This is Fio, 2 to I Ppb
This is because the influence of the α rays emitted from the protective film on malfunction of the device decreases rapidly after . The total content of α-ray source materials such as uranium and thorium in the obtained protective film was 0.2
- If it exceeds 1 ppb, the total content of α-ray source substances such as uranium and thorium can be reduced by purifying the monomers and solvents used in the production of the resin, precipitants used in the purification of the resin, organic liquids, etc. can be reduced. Purification involves distillation, sublimation, recrystallization, extraction, etc. of monomers, solvents, precipitants used in resin purification, organic liquids, etc. used in resin production, and poor solvents used to purify the synthesized resin solution. It is convenient to carry out the precipitation step several times.

In addition, in order to reduce corrosion and leakage during use, the content of ionic impurities such as sodium, potassium, copper, iron, etc. is preferably 2 ppm or less, more preferably 1 ppm.
m or less. If the total content of ionic impurities in the obtained film exceeds 1 to 2 PPm, the total content of ionic impurities can be reduced by purifying the monomers used in the production of the above resin in the same process as the above purification. The content can be reduced.

It is not necessary to purify all of the monomers used. For example, only the monomer or the monomer and the bath agent may be purified.

The IC in the present invention includes a monolithic IC, a hybrid IC, a multi-chip high-density mounting board, and the like.

A monolithic IC 1 has the structure shown in FIG. 3, for example. 9 The heat-resistant resin paste of the present invention is coated on the LSI chip 2 and heated to form a heat-resistant resin film 1 (surface protection film). .

In Fig. 3, 1 is a heat-resistant resin film, 2FiLS
I chip, 3 is a bonding wire, 4Fi resin pancake, 5 is a lead, and 6 is a support body.

For example, an hybrid IC has a structure shown in FIG. 4, in which a heat-resistant resin paste according to the present invention is coated on the first layer wiring 11 and the resistance layer 12, and heated to form a heat-resistant resin film. 10 (interlayer insulating film). On top of this, the second
Layer wiring 9 is formed.

In Figure 4, 7 is a diode chip, 8 is a solder,
9#: 2nd layer wiring, 10 pieces heat-resistant resin film.

11 is a first layer wiring, a 12Fi resistance layer, and a 13Fi alumina substrate.

The multi-chip high-density mounting board has the structure shown in FIG. Engineering.

By repeating the formation of the heat-resistant resin film 14 (interlayer insulating film) by heating, etc., the copper/heat-resistant resin multilayer N layer 19 is formed. In FIG. 5, there are 17 LSI chips and 18 is solder.

(Example) Next, one F! A will be explained using comparative examples and examples.

Comparative Example 1 (1) Preparation of heat-resistant resin While passing nitrogen gas through a four-hole flask equipped with a thermometer, stirrer, and nitrogen inlet tube, 1, 1, 1.3, 3°3-
Hexafluoro-2,2-bis(4-aminophenyl)
0.05 mol of propane, 0.05 mol of 2.4'-diaminodiphenyl ether, 0.10 mol of 4.4'-oxycyphthalic anhydride, and 400 g of N-methylpyrrolidone were charged. Thus, the reaction was allowed to proceed in the room for 12 hours. Next, 143 g of acetic anhydride and 729 g of pyridine were added, and the mixture was allowed to stand at room temperature for 12 hours.

This solution was dropped into water, and the precipitated solid resin in the form of fine particles was collected. After thoroughly boiling and washing this solid resin with methanol, it was dried under reduced pressure at 80°C for 10 hours to obtain a reduced viscosity (using dimethylformamide as the solvent, sample concentration of 0.59).
/de measured at 30℃, the same applies hereafter) 0.71 (di
/9) A polyimide resin having a guushigaeshi unit of the following formula was obtained.

(2) Preparation of fine particles of heat-resistant resin Pyromellitic dianhydride 2189 (1 mol) and N- The mixture was placed in 1672 g' of methylpyrrolidone (moisture 0.03%), heated to 50° C. with stirring, and kept at the same temperature for 0.5 hours to completely dissolve and form a homogeneous solution. To this, 4.4'-diaminodiphenyl ether 1009 (0.5 mol) and 4.4
'-Diaminodiphenylmethane 999 (0.5 mol) was added, the temperature was immediately raised to 110°C, and the mixture was kept at the same temperature for 20 minutes to completely dissolve and form a homogeneous solution. Then, the temperature was raised to 200°C over about 2 hours, and the reaction was continued at the same temperature for 3 hours.

During the process, precipitation of polyimide resin particles was observed at about 140°C. Further, during the 9 reactions, distilled water was promptly removed from the system.

Fine particles of yellow-brown polyimide resin dispersed in N-methylpyrrolidone were obtained, which were recovered by filtration.
After repeating the acetone boiling twice, it was heated to 200 ml under reduced pressure.
It was dried at ℃ for 5 hours. The shape of the fine particles of this polyimide resin was approximately spherical, porous and loose, and the average particle diameter (by Coulter Electronics 2 Co., Ltd., model TA-It; hereinafter the same) was less than #'i 8 .mu.m and maximum particle diameter Fi 40 .mu.m. The fine particles of this polyimide resin are insoluble in N-methylpyrrolidone and have linear repeating units.

(3) Preparation of paste 30 g of the polyimide resin particles prepared in (2) above were added to a solution of polyimide resin 129 prepared in (1) above dissolved in N-methylpyrrolidone 689, and first roughly kneaded in a mortar. Then, the mixture was kneaded six times using a high-speed triple roll to obtain a paste in which fine particles were dispersed.

Example 1 (1) Preparation of heat-resistant resin Bis[4-(3-aminophenoxy)phenyl]sulfone 43Z499 (1 mol) was added while passing nitrogen gas through a four-bottle flask equipped with a thermometer, stirrer, and nitrogen inlet tube. )
, 4.4'-oxycyphthalic anhydride 294.719 (
0.95 mol), [1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane] dianhydride 21.339 (0.05 mol) and N-
Methylpyrrolidone 29909 was charged. Under this pressure, the reaction proceeded at room temperature for 12 hours. Then, acetic anhydride 1430
9 and 714 g of pyridine were added, and the mixture was left to stand at room temperature for 12 hours. This solution was dropped into water, the precipitated solid resin in the form of fine particles was thoroughly boiled and washed with methanol, and then heated to 80°C for 1 hour.
By drying under reduced pressure for 0 hours, a polyimide resin having repeating units of the following formula, which was soluble in γ-butyrolactone and had a reduced viscosity of 0.69 (dl/g), was obtained.

(2) Preparation of fine particles of heat-resistant resin While passing nitrogen gas through a four-bottle flask equipped with a thermometer, stirrer, and nitrogen inlet tube, 2-bisC4-C4-aminophenoxy)phenyl]propane 410.529 (
1 mol), 4,4'-oxycyphthalic anhydride 294.
719 (0.95 mol), [1゜3-bis(λ4-dicarboxyphenyl)-1,1゜3.3-tetramethyldisiloxane] dianhydride 21.339 (0.05 mol)
and N-methylpyrrolidone 2900st. Under this pressure, the reaction proceeded at room temperature for 10 hours. The viscosity of the reaction system is such that it is difficult to stir due to the formation of high molecular weight polyamic acid.
It went up to . A small amount of water was added and heated to 60°C to adjust the molecular weight. Next, 1430 g of acetic anhydride and 714 g of pyridine were added, and the mixture was left at room temperature for 12 hours.

The obtained solution was poured into methanol, and the precipitated solid resin in the form of fine particles was recovered. After thoroughly boiling and washing this solid resin with methanol, it was dried under reduced pressure at 80°C for 10 hours to obtain a powdered polyimide resin (reduced viscosity: 0.68 de/
9) was obtained.

This polyimide resin is pulverized using a pulverizer, and the average particle size is 4.
．． Fine particles of a polyimide resin having a repeating unit of the following formula, which does not dissolve in γ-phthyrolactone at room temperature but dissolves upon heat curing, with a maximum particle diameter of 40 μm or less were obtained.

(3) Preparation of heat-resistant resin paste Add fine particles 239 of the polyimide resin of the above (2) to a solution of 15 g of the polyimide resin of the above (1) dissolved in kr-butyrolactone 629, first coarsely kneading in a mortar, then high speed The mixture was kneaded six times using a three-roll roll to obtain a heat-resistant resin paste in which fine particles of polyimide resin were dispersed.

Example 2 (1) Preparation of heat-resistant resin 200.249 (1 mol) of 2,4'-diaminodiphenyl ether was added while passing nitrogen gas through a four-bottle flask equipped with a thermometer, a stirrer, and a nitrogen inlet tube.

1.1,1. a3,3”xafluoro=2+2-bis(3+4-dicarboxyphenyl)propanihydride 4
44.24g (1 mol) and 258g of N-methylpyrrolidone
I prepared 09i. The reaction was allowed to proceed for 12 hours under the conditions of pressing and mixing in the room.

Next, acetic anhydride 14309 and pyridine 7149 were added, and the mixture was left at room temperature for 12 hours. This solution was dropped into water, and the precipitated solid resin in the form of fine particles was sufficiently boiled and washed with methanol, and then dried under reduced pressure at 80°C for 10 hours. (c1g/
A polyimide resin having repeating units of the following formula (9) was obtained.

(2) Preparation of fine particles of heat-resistant resin As the monomer diamine component and tetracarboxylic dianhydride component, 200.249 (1 mol) of 4,4'-diaminodiphenyl ether and bis(3°4-dicarboxyphenyl) were used. Dimethylsilan dianhydride 352379 (
1 mol) and N-methylpyrrolidone 25 as the solvent.
The process was carried out in exactly the same manner as in Example 1 (2) except that 809 was used, and the average particle size was 3 μm and the maximum particle size was 40 μm or less. Fine particles of polyimide resin (reduced viscosity: 0.63 de/g) having repeating units of the formula were obtained.

H3 (3) Preparation of heat-resistant resin paste - Polyimide resin 15 prepared in (1) above, γ =
The polyimide resin fine particles 209 prepared in (2) above were added to the solution dissolved in valerolactone 659.

First, the mixture was roughly kneaded in a mortar and then kneaded six times using a high-speed triple roll to obtain a heat-resistant resin paste in which fine particles of polyimide resin were dispersed.

Example 3 (1) Preparation of fine particles of heat-resistant resin 2,2-diaminodiphenyl ether 200.
249 (1 mol), 4'4.4'-benzophenonetetracarboxylic dianhydride 290.019 (0.9 mol)
and [1,3-bis(3,4-dicarboxyphenyl)
-1,1,3,3-tetramethyldisiloxane dianhydride 42.659 (0.1 mol) was used.

The procedure was carried out in exactly the same manner as flJ 1 (2+) except that N-methylpyrrolidone 21309 was used as the solvent.
A polyimide resin with linear repeating units that does not dissolve in propylene carbonate at room temperature but dissolves during heat curing (
Fine particles with reduced viscosity i: 0.58 de/9) were obtained.

(2) Preparation of heat-resistant resin paste The polyimide resin particles 189 from (1) above were added to a solution of the polyimide resin 159 prepared in Comparative Example 1 (1) dissolved in propylene carbonate 709, and first roughly kneaded in a mortar. , then kneaded 6 times using three high-speed rolls,
A heat-resistant resin paste in which fine particles of polyimide resin were dispersed was obtained.

Example 4 (3,3.'4.
4'-benzophenone tetracarboxylic dianhydride 11.
6029 (0,0360 mol) was recrystallized from a mixture of toluene and diethyl ether at a polymerization ratio of 1:1 [1.
3-bis(3,4-dicarboxyphenyl) -1,1
,3,3-tetramethyldisiloxane] dianhydride 0.8
089 (0,0019 mol), γ-caprolactone 639 purified by vacuum distillation, and ethanol 289 were charged while passing nitrogen gas. The mixture was reacted at 100° C. for 2 hours with stirring to obtain a mixture of tetracarboxylic dianhydride and its half ester. After cooling to room temperature, 7.5899 (0,0379 mol) of 2,4'-diaminodiphenyl ether recrystallized from a mixture of methanol and water at a polymerization ratio of 8=2 (methanol:water) was charged.

The reaction was carried out in a room for 10 hours to obtain a solution of polyamic acid ester oligomer.

(2) Preparation of fine particles of heat-resistant resin In a fourth flask equipped with a temperature meter, a stirrer, a 9 element inlet tube, and a moisture meter, 3 was purified by recrystallization from acetic anhydride.
, a, '4.4'-benzophenonetetracarboxylic dianhydride 6.1069 (0,0190 mol) and 3,3.
'4.4'-Biphenyltetracarboxylic dianhydride5.
5789 (0,0190 mol), recrystallized using a mixture of toluene and diethyl ether in a weight ratio of 1=1 [1,3-bis(3,4-dicarboxyphenyl) -
1,1,3,3-tetramethyldisiloxane dianhydride 0.8519 (0,0020 mol).

The weight ratio of methanol and water is 8=2 (methanol:water)
7.9939 (0,0400 mol) of 2,4'-diaminodiphenyl ether recrystallized using a mixed solution of and 846 t- of N-methylpyrrolidone purified by vacuum distillation.
It was prepared while passing nitrogen gas through it. Press down, 10 at room temperature
After proceeding with the reaction for an hour, the temperature was raised to 185°C, and at the same temperature 10
The time reaction proceeded. in the middle.

The distilled water was promptly removed from the reaction system. The resulting solution was diluted with 735 g of N-methylpyrrolidone purified by vacuum distillation to obtain a solution having a resin concentration of 25% by weight. This was spray-dried using a Mobil Minor type spray dryer manufactured by Ashizawa Niro Atomizer Co., Ltd. to form fine particles, and then classified into γ-caprolactone with an average particle size of 3 μm and a maximum particle size of 40 μm or less. Fine particles of a polyimide resin having a repeating unit of the following formula which dissolves when dissolved were obtained. Reduced viscosity FiO1 of this polyimide resin
Meriyuki at 62dJ/9.

(3) Preparation of heat-resistant resin paste Add 259 particles of the polyimide resin from (2) above to 75 g of the polyamic acid ester oligomer solution (resin concentration: 26.6] it) from (1) above, and first, place in a mortar. The mixture was roughly kneaded and then kneaded six times using three high-speed rolls to obtain a heat-resistant resin paste in which fine particles of polyimide resin were dispersed. When the solvent was removed from this paste and the contents of uranium and thorium were examined by activation analysis, they were each below the detection limit of 0.02 ppb, and o, osp.
It was less than pb. Also, sodium, potassium, copper,
The content of iron ionic impurities was less than 2 ppm, respectively.

Next, apply this paste to the density of 16 on the surface of the MO8A type RAM with the screen mark #1.
00℃, 150℃, 200℃, 250'C and 350℃
Heat treatment was performed for 0.5 hours each.

A polyimide purulent membrane having a thickness of about 20 μm was formed. The obtained semiconductor element was then sealed at about 450° C. using a ceramic package using low melting point glass as a sealing adhesive. The soft error rate of this semiconductor device was u30fit.

The pastes obtained in Comparative Example 1 and Examples 1 to 4 were transferred onto the various substrates shown below. Screen printing was performed so that the film thickness of the paste was almost constant, and the pastes were screen printed at 100° C. for 1 hour at 200° C.
℃ for 0.5 hours, 250℃ for 0.5 hours, then 350℃
The following properties of the film obtained by baking for 0.5 hours were evaluated, and the results are shown in Table 2.

The pinhole density was determined by using an aluminum plate as the base material and adding an appropriate amount of phenolphthalein to the surface of the film.
Fill with 2% saline solution and use this solution as the positive electrode.

Using an aluminum plate as a negative electrode, a DC voltage of 20 V was applied for 1 minute, and the number of pinholes generated was measured.

The tensile strength was measured using a tensile tester (Tensilon Universal Tester Model UCT-sT manufactured by Orientic Co., Ltd.) using a glass plate as a base material and the film peeled from the glass plate. The glass transition temperature was measured for the film peeled off from the glass plate using a differential scanning calorimeter (Model 910 manufactured by DuPont) at a heating rate of 5° C./min.

The film thickness was measured using an electromagnetic film thickness meter.

Scanning electron micrographs of cross sections of films obtained from Comparative Example 1 and Example 40 pastes are shown in FIGS. 1 and 2.

From Table 2, it can be seen that the heat-resistant resin pastes of Examples 1 to 4, which combined a specific heat-resistant resin, heat-resistant resin fine particles, and solvent, were mixed into the film and Comparative Example 1 in which the filler remained intact.
It is shown that the pinhole density and tensile strength, which are indicators of film uniformity, are significantly superior to that of the zero paste.

Furthermore, the heat-resistant resin pastes of Examples 1 to 4 have sufficient thixotropic properties and film heat resistance (glass transition temperature).

A scanning electron micrograph of the cross section of the film obtained in Comparative Example 1 (Fig. 1) shows that the fissures contained in the film remained as they were, and many voids were observed on average.
A similar cross-sectional photograph (FIG. 2) shows that the film obtained in Example 4 is an extremely uniform film, with no residual fisi or voids observed.

(Effects of the Invention) The heat-resistant resin paste of the present invention can be applied by screen printing and has 1% pinholes.

A uniform film with few voids can be formed, and a high degree of heat resistance, mechanical properties, moisture resistance, and corrosion resistance can be obtained.

Furthermore, it is possible to impart appropriate thixotropy, and excellent pattern accuracy can be obtained by printing.

[Brief explanation of the drawing]

Figure 1 is a scanning electron micrograph showing the particle structure of the film obtained from the paste of Comparative Example 1, and Figure 2 is the particle structure of the film obtained from the heat-resistant resin paste of Example 4. Scanning electron micrograph showing. Fig. 3 is a cross-sectional view of a monolithic IC using the heat-resistant resin paste of the present invention, Fig. 4 is a cross-sectional view of a hybrid IC using the heat-resistant resin paste of the present invention, and Fig. 5 is a cross-sectional view of a hybrid IC using the heat-resistant resin paste of the present invention. 1 is a cross-sectional view of a multi-chip high-density mounting board using a synthetic resin paste. Explanation of symbols 1 Heat-resistant resin film 3 Bonding wire 4 Resin package 6 Support 8 Solder 10 Heat-resistant resin film 12 Resistance layer 14・・Heat resistant resin film 16 ・Wiring layer 18 ・Solder 19 ・Copper/heat resistant resin multilayer wiring layer 20 ・Ceramic multilayer wiring board 2 ・LI8 chip 5 ・Lead 7 ・...Diode chip 9...Second layer wiring 11...First layer wiring 13...Alumina substrate 15...Wiring layer 17...LSI chip FIG. 9・Second layer wiring 11・...Fourth layer wiring 13 Alumina substrate No. 5

Claims (1)

[Scope of Claims] 1. Contains a heat-resistant resin, fine particles of the heat-resistant resin, and a solvent; before heat curing, the fine particles exist as an average of one phase in a homogeneous phase consisting of the heat-resistant resin and the solvent; The final product is a heat-resistant resin paste in which the heat-resistant resin, fine particles, and solvent exist as a homogeneous phase. 2. The heat-resistant resin paste according to claim 1, wherein the heat-resistant resin is a polyamide resin, a polyamide-imide resin, or a polyimide resin. 3. The heat-resistant resin paste according to claim 1 or 2, wherein the fine particles are polyamide resin, polyamideimide resin, or polyimide resin with an average particle diameter of 40 μm or less. 4. The heat-resistant resin paste according to claim 1, 2 or 3, wherein the solvent is a lactone or a carbonate. 5. The heat-resistant resin paste according to claims 1 to 4, wherein the paste has a thixotropy coefficient of 1.5 or more. 6. An IC having an interlayer insulating film and/or a surface protection film obtained from the heat-resistant resin paste according to any one of claims 1 to 5.