JPS61221219A - Epoxy resin composition for sealing semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a resin composition which can give a cured product showing excellent heat shock resistance, by mixing an epoxy resin with a novolak phenolic resin, a phenol/aldehyde resin and a polyvinyl acetal compound at a specified ratio. CONSTITUTION:A resin composition comprising 100pts.wt. epoxy resin (a) having at least two epoxy groups in the molecule, 10-50pts.wt. novolak phenolic resin (b), 10-50pts.wt. phnol aralkyl resin (c) and 2-40pts.wt. polyvinylacetal compound (d), wherein the total of (b)+(c) is 10-90pts.wt. As the epoxy resin used, one having a softening point of 70-85 deg.C or one having an epoxy equivalent of 175-220 is particularly preferable. Resin (b) functions as a curing agent for epoxy resin (a) and a resin having softening point of 80-100 deg.C or one having a hydroxyl equivalent of 100-110 is particularly desirable.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an epoxy resin composition for encapsulating semiconductor devices,
More specifically, the present invention relates to an epoxy resin composition for encapsulating semiconductor devices that provides a cured product having excellent thermal shock resistance.

[Technical background of the invention and its problems]

In recent years, in the field of encapsulation of semiconductor devices, as semiconductor devices have become highly integrated, various functional units on devices have become finer and device pellets themselves have become increasingly fatigued.

Due to these changes in element pellets, conventional sealing resins are no longer able to satisfy requirements such as thermal shock resistance. Epoxy resin compositions cured with phenol novolac resins, which have been conventionally used as sealing resins for semiconductor devices, have excellent hygroscopicity, high-temperature electrical properties, moldability, etc., and have become the mainstream resin for molding.

However, when this type of resin composition is used to completely seal a large device pellet with a fine surface structure, phosphosilicate glass (PSG), which is a coating material to protect the aluminum CAL) pattern on the surface of the device pellet, is formed. Cracks occur in the film or silicon nitride (SiN) film. t) The element pellet is cracked and removed.

This tendency is particularly pronounced when a thermal cycle test is performed. As a result, defects such as defects in device characteristics due to pellet cracks and defects due to corrosion of the AL pattern due to cracks in the protective film occur.

As a countermeasure, the stress on the internal sealing resin is reduced, and the PSG film or SiN film on the sealing resin and the element is
It is necessary to increase the adhesion with glass films such as membranes.

Moreover, regarding the cured product, is there corrosion of the AL pattern on the element surface? In order to prevent this as much as possible, it is necessary to keep the concentration of hydrolyzable halogen compounds, especially chlorine, low, and to maintain high electrical insulation performance during moisture absorption and at high temperatures.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide an epoxy resin composition for encapsulating a semiconductor device that provides a cured product having excellent thermal shock resistance.

[Summary of the Invention] The epoxy resin composition for encapsulating a semiconductor device of the present invention comprises: a) 100 parts by weight of an epoxy resin having at least two epoxy groups in one molecule; b) 10 to 50 parts by weight of a novolac type phenol resin; C) 10 to 50 parts by weight of a phenolic aralkyl resin, and the total amount of (b) + (c) is 50 to 90 parts by weight; be.

Epoxy resin (a) which is one component in the composition according to the present invention
) may be of any type as long as it has at least two epoxy groups in one molecule; for example, bisphenol A type epoxy resin, novolac type epoxy resin, alicyclic type epoxy resin, glycidyl ester type epoxy resin. These may be combined. Specific examples of these epoxy resins include %EOCN-1028
(Nippon Kagyo #, softening point 74℃, epoxy equivalent 215)
, ECN-1273 (Ciba Geigy, softening point 73
°C, epoxy equivalent 230), EPPN-201 (
Nippon Kayaku @, softening point 5°C, epoxy equivalent 181), Epicote 1001 (Shell Chemical, softening point 70°C, epoxy equivalent 475), Chissonox 201 (Tisso ■ 1 viscosity 1800 cpa (25°C), epoxy equivalent 154) .

Chisson Knox 289 (Chisso ■, viscosity 870 cps
(25°C), epoxy equivalent: 219), etc.

Among the above epoxy resins, those having a softening point of 60 to 100°C are preferred, and those having a softening point of 70 to 85°C are particularly preferred. Also, those having an epoxy equivalent of 100 to 300 are preferable, particularly preferably 175 to 220.
It has the following.

This component (a) preferably contains epoxy resin 100%
It is constructed by adding up to 30% by weight of a flame retardant epoxy resin based on the weight part.

The novolac type phenolic resin (b) according to the present invention is (a
Examples of the curing agent for the epoxy resin component () include those having t-2 or more phenolic water groups such as phenol novolac resin and cresol novolac resin. Among the novolak type phenolic resins, those having a softening point of 60 to 120°C are preferred, particularly those having a softening point of 80 to 100°C, and those having a hydroxyl equivalent of 100 to 150 t- are preferred, particularly preferably 100 to 120°C. 110t-.

The phenol aralkyl resin (C) related to Kinoi 1jlK is aralkyl ether and phenol *y! J -chill-
It is a resin reacted with a Krach catalyst and is also called Friedel Krach type resin. α,α′-dimethoxy-para-
The m alloy x gold compound of xylene and phenol monomer is well known (Plastics VoL 34°No.
2, P85). Specifically, XL-225 (
Mitsui Toatsu Chemical ■, Softening point 85℃~105℃), XY
Examples include LOK-225 (Albright and Wilson ■, softening point 85°C to 105°C). Among these phenolic aralkyl resins, the softening point is 80°C to 120°C.
2 is preferred, particularly preferably 85°C to 10
5°C, and the hydroxyl equivalent is 195 to 235.
Those with t- are preferred.

The amounts of (b) and (c) added above are preferably such that the total amount of -(b)+(c) is in the range of 50 parts by weight to 90 parts by weight based on 100 parts by weight of the epoxy resin. If the blending ratio is less than 50 parts by weight, the strength of the cured resin product will be weak, which is undesirable. On the other hand, if it exceeds 90 parts by weight, the moisture resistance of the sealing resin will decrease, which is undesirable. The amounts of novolac type phenol resin and phenol aralkyl resin to be added are within the range that satisfies the above conditions, and each is 1
It can be selected within the range of 0 parts by weight to 50 parts by weight.

If the phenol resin is less than 10 parts by weight, sufficient hardness of the molded product cannot be obtained;
If the amount is less than 1 part by weight, sufficient thermal shock resistance cannot be obtained.

On the other hand, if the phenol resin is 50 parts by weight or more, sufficient moisture resistance cannot be obtained, and if the phenol aralkyl resin is 50 parts by weight or more, the viscosity is high and moldability is poor.

The polyvinyl acetal compound (a) according to the present invention is a polyvinyl hexylal resin, a polyvinyl propional resin, a polyvinyl acetoacetal resin, a polyvinyl butyral resin, a polyvinyl acetal resin, a polyvinyl butyral resin, ≠+φ・Ginkasa--Tan=Sho- Specific examples of these polyvinyl acetal resins include Eslec Bus (Tanesui Kagaku ■, viscosity of a 10% solution in ethanol/toluene = 171 at 25°C, 80-150 CpB% butyral group). 70 molti or more], Eslec BL-I C water coating chemistry ■, viscosity 2
5°C 10-30cps, butyral group 63 molti], Eslec BL-8 [Tanesui Kagaku ■, viscosity 25°C 10-30
cps *butyral group 70 mol or more], Vinylec B-2 [Tisso ■, formal content 81 mol or more], and the like.

Among the polyvinyl acetal compounds, viscosity (25
5 to 400 cps (measured at °C) (however, the viscosity of a 10% solution of ethanol/toluene + 1/1) is preferred, and particularly preferably 10 to 200 cps.

The blending ratio of component (d) is usually 2 to 40 parts by weight, preferably 10 to 30 parts by weight. If the blending ratio is less than 2 parts by weight, the effect of improving thermal shock resistance will not be sufficient, and if it exceeds 40 parts by weight, the moldability of the resin will deteriorate, which is not preferred.

Next, a method for manufacturing the epoxy resin composition for semiconductor device enclosure according to the present invention will be described.

The composition of the present invention can be prepared by melt mixing the above-mentioned components using a heating roll, melt mixing using a kneader, melt mixing using an extruder, mixing using a special mixer after pulverization, or an appropriate combination of these methods. It can be easily manufactured by t.

Note that the composition of the present invention may optionally contain a curing accelerator such as imidazole or a derivative thereof, a tertiary amine derivative, a phosphine derivative, a cycloamidine derivative; zircon, silica, fused silica glass, alumina, hydroxide. aluminum, glass, quartz glass, calcium silicate,
Gypsum, calcium carbonate, magnesite, clay, kaolin, Merck, iron powder, copper powder, mica, asbestos, silicon carbide, boron nitride, molybdenum dioxide, lead compounds, lead oxide, zinc white, titanium white, carbon powder fillers such as higher fatty acids, mold release agents such as waxes; coupling agents such as epoxysilane, vinylsilane, aminosilane, borane compounds, alkoxy titanate compounds, aluminum chelate compounds; antimony, phosphorus compounds, bromine and chlorine Known flame retardants including these may also be blended. Furthermore, various improvers such as silicone oil may be added for the purpose of improving thermal shock resistance and the like.

〔Effect of the invention〕

As described in detail above, the cured product of the epoxy resin composition for encapsulating semiconductor devices of the present invention has excellent thermal shock resistance, and has practical value in applications such as highly integrated semiconductor devices. can be said to be extremely large.

The present invention will be explained in more detail below with reference to Examples and Comparative Examples.

In addition, in Examples and Comparative Examples, all "parts" indicate "parts by weight."

[Embodiments of the invention]

Example 1 Orthocresol novolac type epoxy resin (ESCN
~195XL: Sumitomo Chemical ■) (softening point near 6°C, epoxy equivalent: 206) 100 parts, brominated phenol novolak epoxy resin (BREN-8: Nippon Kayaku ■) (bromine content 230%, softening point = 87 °C, epoxy equivalent: 27
0) 18 parts, phenol novolak resin (BRM-55
8: Showa Union Synthesis ■) Softening point: 98°C, hydroxyl equivalent: 104) 36 parts, phenol aralkyl resin (XL-
225: Mitsui Toatsu Chemical ■) (softening point 95°C, hydroxyl equivalent 196) 36 parts, polyvinyl butyral (ethanol/
Viscosity in 10qb toluene solution (25℃): 100
cps.

Furthermore, 1.5 parts of triphenylphosphine as a curing accelerator, 1 part of carnauba wax as a mold release agent, 1.8 parts of carbon powder as a coloring agent, and 505 parts of fused silica as a filler.

15 parts of antimony trioxide powder as a combustion aid, 2.4 parts of an epoxy silane coupling agent for surface treatment of the filler.
The epoxy resin composition for encapsulating a semiconductor device of the present invention is prepared by blending the epoxy resin composition for encapsulating a semiconductor device of the present invention.

A low pressure transfer molding machine (
175℃, 80Kv/
aA, A large pellet evaluation sample element (8w x 8m) having PSG#'e on the surface was sealed for 120 seconds.9.

To evaluate the thermal shock resistance, mechanical properties (flexural modulus 1 bending strength), and thermal properties (glass transition point, coefficient of thermal expansion) of the obtained sample element, various tests described below were conducted.

Thermal shock resistance test: Twenty sample elements obtained were rapidly heated and cooled in the range of -65°C to 150°C for the number of cycles shown in the table, and tested for thermal shock resistance to determine whether or not cracks occurred. To check for cracks, melt away the molding resin using fuming nitric acid and check using a microscope.

Bending elasticity HA was measured according to JISK-6911.

The bending strength was measured according to JISK-6911.

The glass transition point was determined from the inflection point of the thermal expansion curve using a thermal dilatometer manufactured by Shinku Riko.

The thermal expansion coefficient was measured using a thermal dilatometer manufactured by Shinku Riko.

Example 2 A composition of the present invention was prepared in the same manner as in Example 1, except that 124 parts of the polyvinyl butyral of Example 1 and 93 parts of fused silica powder 'e4' were used, and all the same evaluation tests were carried out.

The results are shown in the table above.

Example 3 The polyvinyl butyral of Example 1 was converted into polyvinyl formal (softening point: 145°C, vinyl formal-containing medium:
A composition of the present invention was produced in the same manner as in Example 1 except that the composition was changed to 83 tin, and the same evaluation test was conducted. The results are shown in the table.

Example 4 The composition of the present invention 'kMI!' was prepared in the same manner as in Example 1, except that 50 parts of the phenol novolac resin 't and 20 parts of the phenol aralkyl resin were used. ! t, a similar evaluation test was conducted. The results are shown in the table.

Comparative Example 1 The 12 parts of polyvinyl butyral and 36 parts of the phenol aralkyl resin of Example 1 were not used, but the amounts were increased to 55 parts of a phenol novolak resin, and in order to keep the filling amount of the filler constant, fused silica powder was added. A comparative composition was prepared in the same manner as in Example 1, except that the amount was changed to 441 parts, and the same evaluation test was conducted. The results are shown in the table.

Comparative Example 2 Example 1 except that 12 parts of polyvinyl butyral in Example 1 was not used and 12 parts of fused silica powder was added instead.
All compositions for comparison were prepared in the same manner as above, and the same evaluation tests were conducted. The results are shown in the table.

Comparative Example 3 Without using 36 parts of the phenol aralkyl resin of Example 1,
55 parts of phenol novolak resin.

Further, a comparative composition tw4 was prepared in the same manner as in Example 1, except that the total amount of fused silica powder was changed to 423 parts, and all the same evaluation tests were conducted. The results are shown in the table.

Claims (1)

[Scope of Claims] a) 100 parts by weight of an epoxy resin having at least two epoxy groups in one molecule; b) 10 to 50 parts by weight of a novolak type phenolic resin; c) 10 to 50 parts by weight of a phenolic aralkyl resin; ) + (c) in a total amount of 50 to 90 parts by weight; and d) 2 to 40 parts by weight of a polyvinyl acetal compound.