JPS6153320A - Epoxy resin composition for sealing semiconductor device - Google Patents

Abstract

PURPOSE:The titled composition providing a cured material having improved water vapor resistance and thermal shock resistance, obtained by blending a specific epoxy resin with a specified novolak phenolic resin, a specific polyvinyl acetal compound and a specified silicone oil in a specific ratio. CONSTITUTION:(A) 100-125pts.wt. epoxy resin containing two or more epoxy groups in the molecule (e.g., novolak type epoxy resin, etc., preferably having 70-85 deg.C softening point and 175-220 epoxy equivalent) is blended with (B) 40-65pts.wt. novolak type phenolic resin having <=50% ortho formation ratio (preferably 20-30%) (preferably one having 80-100 deg.C melting point and 100- 110 hydroxyl group equivalent), (C) 2-40pts.wt. polyvinyl acetal compound [e.g., polyvinyl butyral, etc., having preferably 100cps viscosity (25 deg.C, in 10wt% ethanol/toluene solution)], and (D) 1-30pts.wt. silicone oil [preferably one having 50,000-500,000cps (20 deg.C) viscosity, to give the aimed composition].

Description

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

[Technical background of the invention and its problems] In recent years, in the field of encapsulation of semiconductor devices, with the increasing integration of semiconductor devices, various functional units on the device have become smaller and the device pellet itself has become larger. It's progressing rapidly.

Due to these changes in element pellets, conventional encapsulating resins are no longer able to meet the requirements. Conventionally, it has been used as a sealing resin for semiconductor devices. Epoxy resin compositions cured with phenol nopolar-2 resin 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 seal a large device pellet with a fine surface structure, phosphosilicate glass (PSG), which is a coating material to protect the aluminum (All) pattern on the surface of the device pellet, is sealed. ) l
Otherwise, cracks may occur in the silicon nitride (Sin) film or in the element pellet.

Particularly when a thermal cycle test is carried out, this tendency is very large, resulting in defects in element characteristics due to pellet cracks and defects due to corrosion of the An pattern due to cracks in the protective film.

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, in order to prevent corrosion of the An pattern on the element surface as much as possible, the cured product contains hydrolyzable halogen compounds, especially chlorine, at a low concentration, and has a high level of electrical insulation performance at high temperatures (such as when moisture is absorbed). need to be kept.

[Object 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 moisture resistance and thermal shock resistance.

[Summary of the invention] The epoxy resin composition for encapsulating a semiconductor device of the present invention is:

a) Epoxy resin having at least two epoxy groups in one molecule 100 to 125 parts by weight b) Novolac type phenol resin with an ortho conversion rate of 50% or less
40 to 85 parts by weight C) Polyvinyl acetal compound 2 to 40 parts by weight d Sealing part silicone oil
It is characterized by comprising 1 to 30 parts by weight.

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. Specific examples of these epoxy resins include EOCN-102S, which may be used in combination.
(Japanese version ■, softening point 74℃, epoxy resin 215)
, ECN-1273 (Ciba Geigy, softening point 73°C
, epoxy equivalent 230), EPPN-201 (Nippon Kagaku ■, softening point 65°C, epoxy equivalent 181), Nipicote 1001 (Shell Chemical, softening point 70°C, epoxy equivalent 475), Chissonox 201 (Tisso ■, viscosity 1800 cps (25°C), epoxy equivalent 154),
Chisson Knox 283 (Chisso ■, viscosity 870 cps
(25°C), epoxy equivalent: 213).

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. In addition, the epoxy equivalent is 100 to 30
0 is preferred, particularly preferably 175
~220.

The blending ratio of component (a) is usually 100 to 125
Based on 100 parts by weight of epoxy resin, 25 parts by weight
Constructed by adding up to % by weight of flame retardant epoxy resin.

The novolac type phenolic resin (b) according to the present invention may be any resin as long as it has an ortho conversion rate of 0 to 50%, for example, a phenolic novolac resin, a talesol novolac resin, etc., which has 2 phenolic hydroxyl groups. or more, preferably an ortho conversion rate of 20 to 3
In this case, the ortho conversion rate refers to the percentage of methylene bonds bonded to the ortho and para positions and the ortho and ortho positions of the phenol hydroxyl group in the structure of the phenol resin. , is defined as the ratio of bonds between ortho and ortho positions. Among the above-mentioned novolak type phenolic resins, if the ortho conversion rate exceeds 50%, the residual stress of the resin increases when sealed, which is undesirable.
Those having a softening point of 60 to 120°C are preferable, particularly preferably those having a softening point of 80 to 100°C, those having a hydroxyl equivalent of 100 to 150 are preferable, and those having too-tio are particularly preferable.

The blending ratio of component (b) is usually 40 to 65 parts by weight, preferably 45 to 55 parts by weight. If the blending ratio is less than 40 parts by weight, the strength of the cured resin product will be weakened, which is undesirable. On the other hand, if it exceeds 85 parts by weight, the moisture resistance of the sealing resin will decrease, which is not preferred.

Examples of the polyvinyl acetal compound (C) according to the present invention include polyvinyl hexylal resin, polyvinyl propional resin, polyvinyl acetoacetal resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl butyral resin, and polyvinyl formal resin. Specific examples of these polyvinyl acetal resins include S-LEC BMS [Sekisui Chemical Co., Ltd.;
150r, pH, butyral group 70 mol% or more], S-LEC BL-1 [1 water chemistry ■, viscosity 25℃ 10-30℃
ps, butyral group 63 mol%], Nislec BL-S
[Sekisui Chemical Flavor, viscosity 25°C 10-30 cps, butyral group 70 mol% or more], Vinylec B-2 [Chisso ■
, formal content of 81% or more].

Among the polyvinyl acetal resins, the viscosity (25℃
The viscosity of a 10-part solution of ethanol/toluene (171) is preferably 5 to 400 cps (measured at 100 cps), and particularly preferably 10 to 200 cps.

The blending ratio of component (c) 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 impact resistance performance will not be sufficient, and if it exceeds 40 parts by weight, the moldability of the resin will deteriorate, which is undesirable.

The silicone oil (d) according to the present invention may be any compound as long as it has a repeating unit of Si-0 and is liquid at room temperature, such as dimethyl silicone oil and methylphenyl silicone oil. Can be mentioned. Furthermore, modified versions of these silicone oils may be used, such as methylhydrogen silicone oil, polydiorganosiloxane oil, fluorosilicone oil, silicone polyether copolymer oil, furkyl-modified silicone oil, and fatty acid-modified silicone oil. , amino-modified silicone oil,
Examples include epoxy-modified silicone oil. Among the silicone oils, those with a viscosity (20°C) of 500 to 100
It is preferable to have a tL of 0,000 cps, particularly preferably 50,000 to 500 QOOcps.

The blending ratio of component (d) is usually 1 to 30 parts by weight, preferably 2 to B parts by weight. If the blending ratio is less than 1 part by weight, the effect of improving moisture resistance and thermal shock resistance will not be sufficient, and if it exceeds 30 parts by weight, the surface of the cured product will become undesirably stained due to embossed silicone oil.

Next, a method for producing the epoxy resin composition for encapsulating a semiconductor device of the present invention will be described.

The composition of the present invention can be easily produced by melt-kneading the above-mentioned components using heated rolls, melt-kneading using a Ni-Goo, melt-mixing using an extruder, mixing using a special mixer after pulverization, or an appropriate combination of these methods. It is possible to create a proboscis.

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 conductor, a cycloamidine conductor; zircon, silica, fused silica glass, alumina, Aluminum hydroxide, glass, quartz glass, silica calcium,
Gypsum, calcium carbonate, magnesite, clay, kaolin, talc, iron powder, copper powder, mica, asbestos, silicon carbide, boron nitride, molybdenum dioxide, lead compounds, lead oxide, zinc white, titanium white, carbon black, etc. fillers; release agents such as higher fatty acids and waxes; epoxysilane, vinylsilane, aminosilane, poran compounds,
Coupling agents such as alkoxy titanate compounds and aluminum chelate compounds; known flame retardants containing antimony, phosphorus compounds, bromine and chlorine may also be blended.

EXAMPLES Below, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

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

[Embodiments of the invention] 1 shift 1" ortho-cresol novolac type epoxy resin (softening point =
74°C, 100 parts of epoxy equivalent: 21B), brominated phenol novolac epoxy resin (bromine content: 30%)
, Softening point: 87°C, Epoxy equivalent: 270) 14 parts, Phenol novolak resin (ortho conversion rate: 25%, Softening point = 95°C, Hydroxyl equivalent: 104) 50 parts, Polyvinyl butyral (in 10% ethanol/toluene solution) Viscosity (25℃): 100 cpa, butyral base concentration 2%
) 12 parts, dimethyl silicone oil (viscosity: 1000
00 cps), 165 parts of triphenylphosphine as a curing accelerator, 1.2 parts of carnaraba wax as a mold release agent, 1.8 parts of carbon powder as a coloring agent, 405 parts of fused silica powder as a filler, and a flame retardant additive. 70 ~
The epoxy resin composition for encapsulating a semiconductor device of the present invention was prepared by kneading with a twin-screw roll at 100°C, cooling and pulverizing, and tableting.

Using the obtained composition, a low pressure transfer molding machine (
175℃, 80kg/c+w2, 120 seconds) to prepare a large pellet evaluation sample element (
8a+mX 8a+m) was sealed.

Thermal shock test (TCT) and moisture resistance deterioration test (POT) were conducted on the obtained sample element in order to evaluate thermal shock resistance and moisture resistance.

Impact resistance test: The obtained sample element was subjected to each cooling and heating cycle, and characteristic defects were measured. The amount of defects was determined by melting away the molding resin using fuming nitric acid, and checking for cracks using an m-microscope.

Moisture resistance deterioration test: After sealing the element for measuring aluminum wiring corrosion on the surface of the element and exposing it to 2.5 atmospheres of saturated water vapor for each test period, pass/fail is judged based on A or disconnection due to corrosion. did.

The results are shown in the table.

A composition of the present invention was prepared in the same manner as in Example 1, except that the polyvinyl butyral of Example 1 was changed to 24 parts, and the fused silica powder was changed to 393 parts, and the same evaluation test was conducted. The results are shown in the table.

The polyvinyl butyral of Example 1 was converted into polyvinyl formal (softening point: 145°C, vinyl formal content: 83
%), the composition of the present invention was prepared in the same manner as in Example 1, and the same evaluation test was conducted. The results are shown in the table.

Silicone oil (viscosity: 80,000 c
ps) A composition of the present invention was prepared in the same manner as in Example 1, and the same evaluation tests were conducted. The results are shown in the table.

A comparative composition was prepared in the same manner as in Example 1, except that 12 parts of polyvinyl butyral and 15 parts of fused silica powder were added instead of dimethyl silicone oil. A similar evaluation test was conducted. The results are shown in the table.

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.
A comparative composition was prepared in the same manner as above, and the same evaluation test was conducted. The results are shown in the table.

Example 1 except that 3 parts of dimethyl silicone oil in Example 1 was not used and 3 parts of fused silica powder was added instead.
A comparative composition was prepared in the same manner as above, and the same evaluation test was conducted. The results are shown in the table. 11 Mouth IA In place of the phenol novolak resin of Example 1, a roseoctylphenol-modified phenol novolac resin (ortho conversion rate 265%, softening point = 85°C 9 molecular weight: 880
) was used, but a comparative composition was prepared in the same manner as in Example 1, and the same evaluation test was conducted. The results are shown in the table.

[Effects of the Invention] As detailed above, the cured product of the epoxy resin composition for encapsulating semiconductor devices of the present invention has excellent moisture resistance and thermal shock resistance, and is suitable for use in highly integrated semiconductor devices. It can be said that the practical value in such applications is extremely large.

Claims (1)

[Scope of Claims] a) 100 to 125 parts by weight of an epoxy resin having at least two epoxy groups in one molecule b) 40 to 65 parts by weight of a novolac type phenol resin having an ortho conversion rate of 50% or less c) Polyvinyl acetal compound 2 ~40 parts by weight d) An epoxy resin composition for encapsulating a semiconductor device, comprising 1 to 30 parts by weight of silicone oil.