JPS62128162A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide an epoxy resin composition with properties such as low stress, excellent sealing property and humidity resistance by a method wherein a semiconductor element is sealed with the epoxy resin compound containing specific constituents. CONSTITUTION:Silicon powder represented by a formula (RSiO3/2)n (R represents a mono organic radical) and a specific silicon oil are used together for a silicon base material applicable for epoxy resin composition. Such an epoxy resin composition is composed of an epoxy resin (A constituent), a hardener (S constituent), the silicon powder represented by the formula (C constituent) and the specific silicon oil (D constituent) normally powdered or formed into tablets. Said epoxy resin composition is provided with low stress as well as excellent sealing property and humidity resistance especially due to the addition of said C constituent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a highly reliable semiconductor device.

[Conventional technology]

Semiconductor elements such as transistors, ICs, and LSIs are usually sealed with ceramic packages, plastic packages, or the like to form semiconductor devices. The above-mentioned ceramic package has heat resistance in the constituent material itself,
It also has excellent moisture resistance, so it is resistant to temperature and humidity.
Moreover, since it is a hollow package, it has high mechanical strength and can be sealed with high reliability. However, since the constituent materials are relatively expensive and the mass productivity is poor, resin sealing using the above-mentioned plastic package has recently become mainstream. Epoxy resin compositions have conventionally been used for this type of resin sealing, and have achieved good results.

The above epoxy resin composition is particularly composed of an 0-cresol novolac epoxy resin, a phenol novolac resin as a curing agent, a tertiary amine compound as a curing accelerator, fused silica as an inorganic filler, etc. These materials are used in multi-layer molding because of their excellent sealing workability (particularly workability during transfer molding).

[Problem that the invention seeks to solve]

However, technological innovation in the semiconductor field is remarkable, and recently, along with improvements in the degree of integration, element sizes have become larger and
While interconnects are becoming finer, packages are becoming smaller and thinner, and along with this, encapsulation materials for semiconductor devices are also becoming more resistant to stress, heat, and moisture than ever before. Sexuality is now in demand. Conventional epoxy resin compositions for encapsulation have been sufficiently excellent as encapsulating materials for semiconductor elements such as ICs and LSIs, but for example, they are encapsulating materials for large semiconductor devices with 8 pins or more, especially 16 pins or more. In this case, the shrinkage stress applied to the element becomes too large, which tends to cause a decrease in thermal shock resistance and an increase in residual stress.

These shortcomings are particularly noticeable when conducting thermal tests. That is, when a thermal test is performed on the above conventional large-sized semiconductor device, cracks that become moisture intrusion paths occur in the sealing resin and the passivation film that is a protective film for the element. Devices that crack during thermal testing are likely to crack even during normal use, have poor moisture resistance and other properties, and lack reliability as a semiconductor device.

For this reason, it has been proposed to add silicone oil to the sealing resin to reduce stress. Problems such as poor sex may occur.

This invention was made in view of the above circumstances, and by using a special component composition as an epoxy resin composition used for resin encapsulation, it can be sufficiently applied to encapsulation of large semiconductor devices, etc., and has a low cost. The purpose of this invention is to provide a semiconductor device that has extremely excellent properties such as stress resistance, imprintability, and moisture resistance.

Means for Solving Problem C] In order to achieve the above object, the semiconductor device of the present invention has the following features:
The structure is such that a semiconductor element is sealed using an epoxy resin composition containing the following components (A) to (D).

(A) Epoxy resin.

(B) Hardening agent.

(C) Silicone powder represented by the following 2 〇(RSi03y□), l [However, R is a monovalent organic group. (D) A silicone oil having at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, a mercapto group, and a carboxyl group.

In other words, the present inventors have conducted a series of studies focusing on silicone-based materials used in epoxy resin compositions in order to improve the low stress properties of semiconductor devices without impeding the marking properties. This invention was achieved by discovering that the desired objective could be achieved by using a silicone powder represented by the general formula (RSiO37□) in combination with a specific silicone oil.

The epoxy resin composition used in this invention contains an epoxy resin (component A), a curing agent (component B), a silicone powder represented by the above general formula (component C), and a specific silicone oil (component D). which can be obtained by using
It is usually in the form of powder or compressed tablets.

Such an epoxy resin composition can be made into a plastic package with excellent low stress properties, imprintability, and moisture resistance, especially by using the above-mentioned component C, and it is possible to realize a highly reliable semiconductor device. .

The epoxy resin serving as component A of the epoxy resin composition is not particularly limited as long as it is an epoxy compound having two or more epoxy groups in one molecule. That is, various epoxy resins conventionally used as encapsulating resins for semiconductor devices are suitable, and in addition, diglycidyl ether of bisphenol A, epibis type epoxy resin which is a polymer thereof, bisphenol F type epoxy resin, etc. 'Sorcine type epoxy resins, alicyclic epoxy resins, etc. can also be used as suitable epoxy resins.

The novolac type epoxy resin usually has an epoxy equivalent of 160 to 250. Those having a softening point of 50 to 130°C are used, and among these, Taredur novolak type epoxy resin has an epoxy equivalent of 180 to 210°C. Softening point 60-1
) 0°C is generally used. In addition, as a phenol novolak type epoxy resin, the epoxy equivalent is 160
~200°C1 Softening point 60~1)0°C is generally used.

Preferred examples of the curing agent for component B used with the epoxy resin include novolac type phenolic resins, acid anhydrides, and amines, and these can be used alone or in combination.

Examples of the above-mentioned novolac type phenolic resins include phenol novolac resins, cresol novolak resins, bisphenol A novolac resins, etc., which are obtained by condensing phenols such as phenol, cresol, and bisphenol A with aldehydes such as formaldehyde under an acidic catalyst. Among them, those having a softening point of 50 to 130°C are particularly preferred.

Examples of the acid anhydrides include phthalic anhydride, maleic anhydride, methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, methylendomethylenetetrahydrophthalic anhydride, and cyclohexane-1,2-
Examples include dicarboxylic anhydride, cyclohexane-3,4-dicarboxylic anhydride, and ethylene glycol ester of trimellitic anhydride.

The amines include m-phenylenediamine, p-phenylenediamine, 4.4°-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1
．． 5-diaminonaphthalene, 2,4-bis(β-amino-1-butyl)toluene, bis(p-β-amino-1-
butylphenyl) ether, bis(p-β-methyl-〇-aminophenyl)benzene, ■, 3-diamino-4-
Isopropylbenzene, m-xylylenediamine, p-
xylylene diamine, 2,4-diaminotoluene, 2,
6-diaminotoluene, bis(4-aminocyclohexyl)methane, 3-methylhebutamethylenediamine, 4,
4-dimethylhexamethylenediamine, octamethylenediamine, 2,5-dimethylhexamethylenediamine,
Examples include 2,5-dimethylhbutamethylenediamine, 3-methylhbutamethylenediamine, and 1,4-cyclohexanediamine.

The silicone powder of component C used in this invention differs from conventionally known linear polymers, rubber-like silicone rubbers, and silicone compounds such as silicone oil, and has the general formula (RSiO*z□), It is an organopolysiloxane powder having a dense three-dimensional network structure as shown in . That is, this silicone powder has, for example, the following structure (hereinafter referred to as a blank space), and the portion surrounded by dotted lines is a repeating unit.

This silicone powder has a particle diameter of at least 200 μm, since the smaller the particle size, the more favorable effect it has on thermal shock resistance and reduction of residual stress.
It is preferable to use particles with the following particle sizes. In particular, this is true in view of problems such as gate clogging when the epoxy resin composition of the present invention is used in a transfer mold, and the smaller the particle size, the better.

Further, it is preferable that the particle shape of the silicone powder is spherical because it has excellent dispersibility and is more effective in reducing the thermal shock resistance and residual stress of the semiconductor device.

In the formula of the silicone powder, R is a monovalent organic group as mentioned above, and specific examples thereof include methyl group, ethyl group, propyl group, butyl group, cycloalkyl group, etc. Alkyl groups, vinyl groups, alkenyl groups such as allyl groups, aryl groups such as phenyl groups, xylyl groups, aralkyl groups such as phenylethyl groups, or epoxy groups, amine groups, hydroxyl groups, carboxyl groups,
Examples include monovalent organic substituents having a carboxylic acid ester group or a mercapto group.

The silicone powder used in this invention may be a homopolymer in which R is only one of the above organic groups, or a copolymer in which R is two or more of the above organic substituents. good.

In addition, the silicone oil of component D used in this invention is:
A silicone that acts as a modifier for resin systems such as epoxy resins and curing agents and has at least one functional group selected from the group consisting of epoxy groups, amino groups, hydroxyl groups, mercapto groups, and carboxyl groups. Composed of oil. This oil can be used alone or
Several types may be used in combination. The chemical structure of the parts other than the functional groups is preferably polydimethylsiloxane, but a part thereof may be substituted with a phenyl group instead of a methyl group.

Even if the above functional group is bonded to the end of the silicone molecule,
It may be bonded as a side chain.

The molecular weight of such silicone oil is 100 or more.
It is preferably less than ooooo. That is, the molecular weight is 100
If the molecular weight is less than 100,000, the silicone molecules act as a plasticizer for the skeleton of the cured resin, reducing the reliability of the semiconductor device, and conversely, if the molecular weight exceeds 100,000, the silicone molecules have no affinity for the resin system. Substantially, it becomes difficult to chemically react with the resin system, that is, to modify it, and the effect of the present invention is reduced.

Further, the equivalent weight per functional group is preferably 100 or more and 100,000 or less. This is for the same reason as above.

Note that it is preferable that the silicone oil of the present invention is reacted with at least one of the epoxy resin (A component) and the curing agent (B component) in advance, and then mixed with other raw materials.

Moreover, in this invention, other raw materials such as a curing accelerator, a filler, a mold release agent, etc. can be used as necessary in addition to the above-mentioned components A, B, C, and D. As the curing accelerator, any catalyst for the curing reaction of the phenol-cured epoxy resin can be used; for example, 2,4
．． 6-1-li (dimethylaminomethyl)phenol,
Examples include 2-methylimidazole and triphenylphosphine. As the filler, quartz glass powder, silica stone powder, talc, etc. can be used. As the mold release agent, conventionally known long chain carboxylic acids such as stearic acid and palmitic acid, metal salts of long chain carboxylic acids such as zinc stearate and calcium stearate, carnauba wax, ester waxes, etc. can be used. .

The epoxy resin composition used in the present invention can be produced as follows, for example, when a novolac type phenol resin or an acid anhydride is used as the curing accelerator, which is component B. That is, first, the epoxy resin (A
At least one of component) and curing agent (component B) is modified with silicone oil (component D), and this modified product and silicone powder (component C) and, if necessary, a curing accelerator,
Mix other raw materials such as mold release agent and filler, and
It can be produced by kneading for several minutes at 0°C. In addition, when a curing accelerator is used, the gelation time of the resulting epoxy resin composition at 150°C is usually 30 to 30°C.
The amount of addition is adjusted and used so that the time is 90 seconds. On the other hand, when an amine type curing agent is used as the curing agent, it is preferable to melt-knead the silicone powder with the epoxy resin or the curing agent in advance, pulverize it, and tri-blend all the components.

In this invention, the content of the curing agent (component B) is as follows:
A sufficient amount to cure the epoxy resin (component A), that is, 0.4 to 2.0 equivalents, preferably 0.6 to 1.5 equivalents per 1 epoxy equivalent of the epoxy resin.
It is preferred to use equivalent amounts.

More specifically, when a novolac type phenol resin is used as a curing agent per 1 epoxy equivalent of the epoxy resin, it is 0.5 to 2.0 equivalent, preferably 0.8 to 2.0 equivalent.
1.5 equivalents, or 0.4 to 1.2 equivalents when an acid anhydride is used as a curing agent, preferably 0.6 to 1.0 equivalents, and 0.4 to 1.0 equivalents when an amine is used as a curing agent. 5
It is desirable to set the amount to 2.0 equivalents, preferably 0.8 to 1.5 equivalents.

In addition, the content of silicone powder (component C) is at least 2% (hereinafter abbreviated as "%") based on the entire epoxy resin composition, and the amount added together with the inorganic components is 80% or less. It is preferable.

That is, if it is less than 2%, it is necessary to add a large amount of silicone oil to improve low stress properties, resulting in poor marking properties of the resulting semiconductor device. In addition, if the total amount of silicone powder and inorganic components added exceeds 80%, problems will occur with the dispersibility and fluidity of the sealing resin composition.
This is because the resulting semiconductor device is defective because it is not filled with the sealing resin.

Furthermore, the content of silicone oil (D component) is 15% of the epoxy resin composition (A component, B component 10 components, 10 components) excluding additive components such as curing accelerators and fillers.
The following is preferable. This is because if it exceeds 15%, problems tend to occur in the stampability of the resulting semiconductor device.

Sealing of a semiconductor element using such an epoxy resin composition is not particularly limited, and can be performed by a conventional method, for example, a known molding method such as transfer molding.

The semiconductor device obtained in this way has extremely low stress properties, excellent marking properties, and moisture resistance.

Effects of Invention C] As described above, the semiconductor device of the present invention is encapsulated using a special epoxy resin composition containing silicone powder (component C) and silicone oil (component D). Since the plastic buff cage is different from conventional ones made of epoxy resin compositions, it achieves low stress while maintaining sealability, has excellent moisture resistance, and has high reliability. In particular, the special epoxy resin composition mentioned above can be used to encapsulate very large scale integrated circuits (VLSI), etc.
In a large semiconductor device with an element size of 161)1)2 or more, the above-mentioned high reliability can be obtained, and this is the greatest feature.

Next, examples will be described together with comparative examples.

First, an epoxy resin composition was prepared as follows.

[Example 1] 0-Cresol novolak epoxy resin (epoxy equivalent: 220, softening point: 80°C) in a separable flask with a stirrer
) 56 parts by weight (hereinafter abbreviated as "parts") was heated and melted, and 15 parts of aminopropyl polydimethylsiloxane having both ends (amine equivalent: 10,000) were added thereto, and the mixture was stirred at 170° C. for 4 hours. The total amount of the obtained modified product and the phenol novolac epoxy resin (hydroxyl group equivalent: 1) 0. Softening point 80
℃) 28 parts, (Ctl+Si:+z□), organosilicone powder expressed as % (average particle size 50μ) 5
0 parts, 345 parts of fusible silica powder, 2 parts of silane coupling agent (manufactured by Nihon Unicar Co., Ltd., A-186), 2 parts of carbon black, 0 parts of curing accelerator (2,4,6-dorisdimethylaminomethylphenol). 45 parts of mold release agent carnauba wax and 2.5 parts of carnauba wax were heated to 80 to 100°C.
The mixture was melt-kneaded for a minute, cooled, and then ground to obtain a 10-mesh pass powder to obtain an epoxy resin composition for encapsulating semiconductor devices.

[Example 2. 4. 6] Each raw material was used in the formulation shown in Table 1 below, and the types of silicone powder and silicone oil were changed. The intended epoxy resin composition was obtained in the same manner as in Example 1 in all other respects. The types of silicone powders used are shown in Table 2, and the types of silicone oils used are shown in Table 3.

C Examples 3 and 5, Comparative Examples 1 to 3] The amounts of phenolic resin and silicone oil shown in Table 1 were melted and mixed in a separable flask with a stirrer, and the curing accelerator was added in the amount shown in Table 1. was added and stirred and mixed at 170°C for 4 hours. The entire amount of the obtained modified product and the other raw materials shown in Table 1 are melt-kneaded for 3 minutes with heated rolls at 80 to 100°C, cooled, and then ground to obtain a 10-mesh pass powder. A resin composition was obtained. The types of silicone powder and silicone oil used are shown in Tables 2 and 3.

(Hereafter the margin) Table 1 (Hereafter the margin) Table 2 (Hereafter the margin) Table 3 (Hereafter the margin) Next, using the powdered epoxy resin compositions obtained in the above Examples and Comparative Examples, filling was carried out. In order to examine the properties and marking properties, a 42-pin DIP was molded using a 48-cavity mold. The mold used a low pressure transfer molding method. That is, a tablet preheated to 90° C. using a high-frequency heating device was injected into a mold at 175° C. for a set injection time of 20 seconds, and molded for a molding time of 2 minutes.

Bonmark C2M was stamped on the surface of the 42-pin DIP molded product obtained in this way, and after post-curing at 175°C for 5 hours, a load of 500 g was applied with a cotton swab soaked in trichlorethylene, and the number of reciprocations was repeated until it disappeared completely. was determined and evaluated.

For the thermal shock test, 40 elements for the thermal shock test were molded in the same manner and post-cured at 175°C for 5 hours. This sample was immersed in silicone oil at 150°C and -80°C alternately for 5 minutes for 500 cycles, and then the package was heated and dissolved with fuming nitric acid to remove the silicon nitride film, which is a protective film on the element surface. The number of cracks observed was determined and evaluated.The results are shown in Table 4 below.

From the results in Table 4, it can be seen that the height measurements performed were excellent in all of thermal shock resistance, filling properties, and marking properties, and a well-balanced and highly reliable semiconductor device could be realized.

On the other hand, as for comparative products, those without silicone powder have poor marking properties, those without silicone oil have poor filling properties, and those without both have poor thermal shock resistance.

Claims (1)

[Claims] (1) A semiconductor device in which a semiconductor element is sealed using an epoxy resin composition containing the following components (A) to (D). (A) Epoxy resin. (B) Hardening agent. (C) Silicone powder represented by the following formula. (RSiO_3_/_2)_n [However, R is a monovalent organic group] (D) Contains at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, a mercapto group, and a carboxyl group silicone oil.