JPH07179729A - Epoxy resin composition for sealing semiconductor and semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the subject composition for sealing semiconductors, containing an epoxy resin, a curing agent and a specific inorganic filler, hardly causing thick flashes and excellent in local stress properties. CONSTITUTION:This epoxy resin composition for sealing semiconductors contains (A) an epoxy resin such as an epoxidized o-cresol novolak resin, (B) a curing agent such as a phenol novolak type curing agent and (C) an inorganic filler using (i) silica and/or alumina having 5-30mum average particle diameter and (ii) spherical fused silica, having 55-100mum average particle diameter and containing <=5wt.% particles having >=150mum particle diameter at (80/20) to (97/3) weight ratio in an amount of preferably 75-94wt.% (based on the whole composition). Furthermore, semiconductor devices are preferably sealed with a cured product of this composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation and a semiconductor device in which aluminum stress is less damaged by local stress and burr is less likely to occur.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
Examples of the epoxy resin composition used for semiconductor encapsulation include an epoxy resin and a phenol resin as a curing agent,
A compound containing silica or the like as an inorganic filler is generally used. Such an epoxy resin composition has a low viscosity at the time of melting and a high fluidity as compared with other thermosetting resin compositions such as a phenol resin composition, so that it can be applied to fine particles such as LSIs, ICs, and transistors. It is effective for suppressing the damage of various patterns and wires and improving the moisture resistance, and is therefore preferably used for semiconductor encapsulation.

As a recent trend, along with the increase in size of silicon chips and the miniaturization of wiring width, it has been demanded that the expansion coefficient of the semiconductor encapsulating material should be close to that of the silicon chips. It is practiced to increase the compounding amount of the filler to lower the expansion coefficient of the cured product.

Further, when aluminum wiring is formed on a silicon chip, there is a problem that a local stress is generated on the aluminum wiring, and in order to prevent this, coarse particles in the filler are cut.

However, when a die used for molding a semiconductor encapsulant having high abrasion property is performed several thousand times or more, a part of the die has been scraped, which is a conventional method. When using the coarse-grain cut product, the thickness is 40 to 10
There was a problem that a relatively thick burr of 0 μm (hereinafter referred to as “thick burr”) was generated.

The present invention has been made in view of the above circumstances, and provides an epoxy resin composition for semiconductor encapsulation and a semiconductor device which are less likely to cause damage to aluminum wiring due to local stress and have less thickness burrs. The purpose is to provide.

[0007]

Means for Solving the Problems and Actions The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, have found that an epoxy resin composition containing an epoxy resin, a curing agent and a filler is used. , Silica and / or alumina having an average particle size of 5 to 30 μm and an average particle size of 55 to 100 μm, and a particle size of 150 μm
In general, when a filler containing coarse particles is used by blending a filler in which m or more and 5 wt% or less of spherical fused silica are used together in a weight ratio of 80:20 to 97: 3. The present invention has been accomplished by finding that the problem of local stress that occurs is less likely to occur and thick burr can be prevented.

Therefore, the present invention provides an epoxy resin composition containing an epoxy resin, a curing agent and a filler, wherein the filler is (A) silica and / or alumina having an average particle size of 5 to 30 μm. , (B) Average particle size 55 to 1
Epoxy resin composition for semiconductor encapsulation and spherical epoxy fused silica having a particle diameter of 150 μm or more and 5 μm or less at a diameter of 00 μm in a weight ratio of 80:20 to 97: 3, and the composition. Provided is a semiconductor device sealed with a cured product.

The present invention will be described in more detail below. The epoxy resin composition for semiconductor encapsulation of the present invention contains the epoxy resin, the curing agent and the filler as the main components as described above.

As the epoxy resin, various known resins can be used, for example, epoxidized orthocresol novolac resin, epoxidized phenol novolac resin, alicyclic epoxy resin and epoxy resin. Bisphenol resin, substituted or unsubstituted triphenolalkane type epoxy resin, epoxidized biphenyl resin, naphthalene ring-containing epoxy resin, or epoxy resin in which a halogen atom is introduced into these. It should be noted that these epoxy resins are not necessarily limited to one kind in use, and two or more kinds may be mixed and blended.

The curing agent is not particularly limited and may be appropriately selected depending on the epoxy resin used, and examples thereof include amine type curing agents, acid anhydride type curing agents and phenol novolac type curing agents. Among them, a phenol novolac type curing agent is more preferable in terms of moldability and moisture resistance of the composition and can be preferably used. Specific examples of the phenol novolac type curing agent include phenol novolac resin and cresol novolac resin.

The compounding amount of the above-mentioned curing agent is an amount capable of curing the epoxy resin, and can be an amount usually used. When a phenol novolac type curing agent is used, the epoxy group in the epoxy resin and the curing agent are It is preferable to mix them in such a manner that the molar ratio thereof to the OH group is 1: 0.5 to 1: 1.5.

In the present invention, various curing accelerators, such as imidazoles, tertiary amines, phosphine compounds, and cycloamidine compounds, are preferably added for the purpose of promoting the reaction between the epoxy resin and the curing agent. . The blending amount is not particularly limited, but is usually 0.
It is preferably set to 05 to 1% by weight.

Furthermore, in the present invention, a silicone polymer may be added to the composition for the purpose of reducing the stress of the cured product. When a silicone-based polymer is blended, it is possible to significantly reduce the occurrence of package cracks in the thermal shock test of the cured product. Examples of the silicone-based polymer include silicone oil having an epoxy group, an amino group, a carboxyl group, a hydroxyl group, a hydrosilyl group, a vinyl group, etc., a silicone resin, a silicone rubber and the like, and these silicone polymers and organic polymers such as substituted or unsubstituted. Examples thereof include a copolymer with a phenol novolac resin.

The addition amount of the silicone polymer is not particularly limited, but it is usually preferably 1 to 50 parts per 100 parts (part by weight, the same applies hereinafter) of the total amount of the epoxy resin and the curing agent.

Next, in the present invention, as described above, the following fillers (A) and (B) are used. (A) Silica and / or alumina having an average particle size of 5 to 30 μm (B) Spherical fused silica having an average particle size of 55 to 100 μm and a particle size of 150 μm or more is 5% (% by weight, the same applies below) or less

The filler as the component (A) used herein has an average particle size of 5 to 30 μm, preferably 8 to 25 μm. If the average particle size is less than 5 μm, the composition obtained will flow. If it is larger than 30 μm, the local stress becomes large. The filler (A) can be selected from crystalline silica, fused silica and alumina,
The shape thereof does not have to be spherical or crushed.

On the other hand, the filler as the component (B) is effective for reducing the occurrence of local stress and preventing thick burr, and has an average particle size of 55 to 100 μm, preferably 60.
The one having a thickness of ˜90 μm is used. If the average particle size is smaller than 55 μm, the effect of preventing thick burr is not sufficiently exerted, and 10
If larger than 0 μm, use 5% of coarse particles of 150 μm or more
It becomes difficult to suppress below.

The component (B) must have a particle size of 150 μm or more in an amount of 5% or less, preferably 3%.
It is the following. If it exceeds 5%, the problem of local stress tends to occur.

Further, the component (B) is used in an amount of 3 to 20%, particularly 5 to 15%, based on the total weight of the components (A) and (B). If it is less than 3%, a sufficient burr prevention effect cannot be obtained, and if it exceeds 20%, the problem of local stress tends to occur.

The filling amount of the filler composed of the components (A) and (B) is 75 with respect to the entire epoxy resin composition of the present invention.
To 94%, more preferably 80 to
92%. If the filling amount is less than 75%, the coefficient of expansion of the obtained cured product becomes large and the stress characteristics may deteriorate. If it exceeds 94%, the melt viscosity at the time of molding becomes too high, resulting in voids. , Unfilling may occur.

When the above-mentioned filler is used after being surface-treated with a silane coupling agent before use, a composition which gives a cured product having higher moisture resistance can be obtained.

If desired, various additives may be added to the composition of the present invention. For example, waxes such as carnauba wax, release agents such as fatty acids such as stearic acid and metal salts thereof (among others, adhesives). Is preferably used from the standpoint of properties and releasability), flexibility-imparting agents such as organic rubber, pigments such as carbon black, cobalt blue and red iron oxide, flame retardants such as antimony oxide and halogen compounds. , One or more of surface treatment agents such as γ-glycidoxypropyltrimethoxysilane, epoxysilane, boron compounds, silane coupling agents such as alkyl titanate, antioxidants, and other additives. You can

In the production of the epoxy resin composition of the present invention, a predetermined amount of the above-mentioned components are uniformly stirred and mixed, and the mixture is heated in advance at 70 to 95 ° C. with a kneader, roll, extruder or the like. It can be obtained by a method such as kneading, cooling and pulverizing, and a melt mixing method using a mixing roll and an extruder is particularly preferably used. here,
There is no particular limitation on the order of mixing the components.

As described above, since the epoxy resin composition of the present invention is unlikely to generate local stress and has good burr characteristics, it is suitable for sealing semiconductor devices such as ICs, LSIs, transistors, thyristors and diodes. It can also be used effectively for manufacturing printed circuit boards.

Here, when the semiconductor device is sealed,
It can be carried out by adopting a conventionally used molding method such as transfer molding or casting method. In this case, the molding temperature of the epoxy resin composition is 150 to 180.
C. and post cure can be performed at 150 to 180.degree. C. for 2 to 16 hours.

[0027]

EFFECT OF THE INVENTION The epoxy resin composition for semiconductor encapsulation of the present invention can give a cured product excellent in moldability in which local stress failure on aluminum wiring is unlikely to occur and thick burr is less likely to occur. The semiconductor device that can be sealed with the cured product of the composition of the present invention has high reliability.

[0028]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following examples, all parts are parts by weight.

[Examples 1 and 2, Comparative Examples 1 to 3] Epoxy equivalent of 198, 51 parts of epoxidized cresol novolac resin having a softening point of 60 ° C, 6 parts of brominated epoxidized phenol novolac resin having an epoxy equivalent of 280, and phenol equivalent of 1
10, phenol novolac resin 33 with a softening point of 90 ° C
Part, a reaction product of 60 parts of the compound represented by the following formula (a) and 40 parts of the compound represented by the following formula (b),
Triphenylphosphine (0.65 parts), antimony trioxide (10 parts), carnauba wax (1.2 parts), γ-glycidoxypropyltrimethoxysilane (1.5 parts), and carbon (1 part) were mixed in a base, and γ-glycidoxypropyl was added. Silica shown in Table 1 surface-treated with 0.6% of trimethoxysilane was blended in an amount shown in Table 2, and mixed with a mixing roll at 80 ° C.
After melt-mixing for a minute, the mixture was taken out as a sheet and cooled and pulverized to obtain a composition.

[0030]

[Chemical 1]

The composition obtained is shown below (a).
Various tests of (C) were conducted. The results are shown in Table 2. (A) Spiral flow 175 ° C, 70k using a mold conforming to EMMI standard
It was measured under the condition of gf / cm ² . (B) Burr Molding temperature of 175 ±
2 ℃, molding time 180 ± 5 seconds, molding pressure 70 ± 5kg
After the 20 g of the sample was put into the molding machine under the condition of / cm ² , the plunger was quickly lowered, and the pressurization was started within 10 seconds to form a burr length of 0.1 mm at a depth of 75 μm when molding.
To the unit of. The depth in each direction in the figure is the numerical value (unit is μm) shown in FIG. 1, and the width is 4 mm. (C) Number of stress failures (evaluation of local stress) 14-pin DIP mounted with a silicon chip having an aluminum wiring with a wiring width of 5 μm and a molding temperature of 175 ± 2
C, molding time 180 ± 5 seconds, molding pressure 70 ± 5 kg /
After molding under the condition of cm ² , a test body was heated at 180 ° C. for 4 hours to form a test body as an initial state. -50
One cycle consists of 30 minutes at ℃ and 30 minutes at 150 ℃ 2
The number of those having a resistance value between the lead terminals of 1Ω or more after 000 cycles was examined as the number of stress defects. (Parameter;
40)

[0032]

[Table 1]

[0033]

[Table 2]

From the results shown in Table 2, it was confirmed that when the epoxy resin composition of the present invention was used, a cured product which was excellent in burr properties and in which stress defects did not easily occur, that is, excellent in local stress property was obtained. It was

[Brief description of drawings]

FIG. 1 is a plan view showing burrs measuring molds used in Examples and Comparative Examples.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical indication location H01L 23/31 (72) Inventor Kenichi Totsuka 1 Hitomi, Osamu Matsuida-cho, Usui-gun, Gunma 10 Shin-Etsu Chemical Industrial Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Toshio Shiobara 1 Hitomi, Osamu Matsuida-cho, Usui-gun, Gunma Shin-Etsu Chemical Co., Ltd.

Claims (3)

[Claims] 1. An epoxy resin composition comprising an epoxy resin, a curing agent and an inorganic filler, wherein (A) silica and / or alumina having an average particle size of 5 to 30 μm, B) Average particle size 55 to 100 μ
An epoxy resin composition for semiconductor encapsulation, characterized in that spherical fused silica having a particle size of 150 μm or more and 5 wt% or less is used in a weight ratio of 80:20 to 97: 3. 2. Inorganic filler in 75-94 of the total composition.
The composition according to claim 1, which is blended in a weight percentage. 3. A semiconductor device encapsulated with the cured product of the composition according to claim 1.