JPS62254453A - Semiconductor device - Google Patents

Abstract

PURPOSE:To contrive improvement in reliability of the title semiconductor device by a method wherein a sealing work is performed using the special epoxy resin composition containing special organopolysiloxane or an additive reaction product. CONSTITUTION:A semiconductor element is sealed using the epoxy composition containing epoxy resin, novolac phenol resin component and organopolysiloxane indicated by a formula. Said epoxy resin composition is obtained by using epoxy resin, novolac phenol resin, and either of the two kinds of special compounds or both of them. Pertaining to the epoxy resin, any kind of epoxy resin can be used for the sealing of a semiconductor element, if it contains two or more epoxy radicals in a molecule. When the semiconductor element is sealed using the above-mentioned epoxy resin composition, no limitation is established for the material to be used. The R1 in the formula separately mentioned indicates a bivalent organic radical, R2 indicates a 3C or lower alkyl radical or a phenyl radical, and (n) indicates an integral number of 5-200.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a semiconductor device encapsulated with a encapsulating resin composition that has low internal stress and excellent moisture resistance and thermal shock resistance.

[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 and high mechanical strength due to its constituent materials, and has excellent moisture resistance due to its airtight sealing, making it resistant to temperature and humidity and capable of highly reliable sealing. be.

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-mentioned epoxy resin composition is particularly suitable for compositions consisting of an epoxy resin, a phenol resin as a hardening agent, and silica powder as a hardening accelerator and an inorganic filler. It has been awarded for its excellent moldability (especially during transfer molding work).

[Problem that the invention seeks to solve]

However, in recent years, due to technological innovation in the semiconductor field, the degree of integration has improved, the device size has become larger, and the wiring has become finer.Therefore, molding semiconductor devices with this type of encapsulating resin has rarely been a problem. It has been found that stress in the resin, which was not present, can cause cracks in the passivation film and the element itself, as well as misalignment of aluminum wiring. This becomes more noticeable as the dimensions of the element itself become larger. Therefore, as a countermeasure to this problem, the development of a resin that applies less stress to the element (low-stress resin) has become a major issue today. As a method for achieving this objective, it is possible to make the epoxy resin or phenol resin itself flexible or to add a plasticizer. However, doing this poses a problem in terms of reliability because in the case of epoxy resin compositions that use phenolic resin as a curing agent, the glass transition point of the cured resin hardens and the high-temperature electrical properties deteriorate, resulting in a decrease in reliability. be. It is also possible to reduce the stress applied to the element by adding synthetic rubber, etc., but adding synthetic rubber may reduce the adhesion of the resin composition to the semiconductor element and lead frame. , moisture resistance deteriorates and reliability decreases.

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 sealing, it can sufficiently cope with the sealing of materials such as 31, and has low stress properties. The object of the present invention is to provide a semiconductor device having extremely excellent heat resistance and moisture resistance.

[Means for solving problems]

In order to achieve the above object, the semiconductor device of the present invention includes:
A semiconductor device in which a semiconductor element is encapsulated using an epoxy resin composition containing the following components (A) and (B) and further containing at least one of the following components (C) and (D). .

(A) Epoxy resin.

(B) Novolac type phenolic resin.

(C) Organopolysiloxane represented by the following formula (1).

(D) An addition reaction product of an organopolysiloxane represented by the following formula (2) and an epoxy resin represented by the following formula (3).

(Hereinafter, blank spaces) In the present invention, the term "addition reaction product" is used not only to refer to all addition-reacted products, but also to include products that partially contain unreacted raw materials.

That is, the present inventors have conducted extensive research to improve the low stress properties of cured epoxy resin compositions, which are sealing materials, without impairing high-temperature electrical properties or moisture-resistance reliability. The cured product of the epoxy resin composition obtained by adding polysiloxane or the addition reaction product of this organopolysiloxane and a specific epoxy resin has excellent low stress properties and is highly reliable in terms of heat resistance and moisture resistance. This invention was achieved by discovering the following.

The epoxy resin composition used in this invention comprises an epoxy resin (component A) and a novolac type phenol resin (component B).
and one or both of two special compounds (component C, component D), and is usually in the form of a powder or a tablet made by compressing it. .

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 sealing resins for semiconductor devices are suitable, including cresol novolac type epoxy resins, phenol novolac type epoxy resins,
Diglycidyl ether to bisphenol and its polymers such as epibis type epoxy resin, bisphenol F type epoxy resin, and resorcin type epoxy resin.

Alicyclic epoxy resins, heterocyclic epoxy resins, etc. can be used as suitable epoxy resins.

Among these resins, it is preferable to use one that has a melting point above room temperature and is in the form of a solid or highly viscous solution at room temperature.

Further, as the epoxy resin, a novolac type epoxy resin is particularly preferable among the various epoxy resins mentioned above, and among these, a phenol novolac type epoxy resin usually has an epoxy equivalent of 160 to 250 and a softening point of 50 to 130°C.
The cresol novolak type epoxy resin has an epoxy equivalent of 180 to 210. Softening point 60
~110°C is generally used.

The novolac-type phenolic resin as component B, which is used together with the epoxy resin, acts as a curing agent for the epoxy resin, and is a phenol novolak, 0-
Talesol novolac, m-cresol novolac, p
-Taresol novolak, 0-ethylphenol novolak, m-ethylphenol novolak, p-ethylphenol novolak, etc. are preferably used. These novolak resins preferably have a softening point of 50 to 110°C and a phenol equivalent of 70 to 150.

As the organopolysiloxane of component C, an organopolysiloxane having a polysiloxane skeleton represented by the following general formula (1) is used.

Among the compounds represented by the above formula (1), the divalent organic group RI is an unsubstituted or substituted alkylene group, an unsubstituted or substituted phenylene group, or an unsubstituted or substituted aralkylene group. It is preferable to use Here, the term "unsubstituted alkylene group" refers to an alkylene group composed entirely of carbon atoms and hydrogen atoms, and the term "substituted alkylene group" refers to a group in which the hydrogen atoms of the above-mentioned unsubstituted alkylene group are substituted with a substituent. The same applies to unsubstituted phenylene groups, substituted phenylene groups, unsubstituted aralkylene groups, and substituted aralkylene groups. Specifically, it is preferable to use a compound in which the divalent organic group R□ is an unsubstituted alkylene group or phenylene group having 2 to 10 carbon atoms, or an aralkylene group having 7 to 15 carbon atoms.

Furthermore, among the compounds represented by the above formula (1), those in which both R2 are methyl groups are preferred.

The organopolysiloxane of formula (1) above has a molecular weight of 5
00 to 20,000 is desirable, and among these, those of about 500 to 5,000 are particularly preferably used. 5
This is because if it is less than 00, there will be little effect on low stress properties, and if it exceeds 20,000, the reactivity with the epoxy resin will deteriorate.

Component D used in this invention is a special addition reaction product obtained by reacting a specific organopolysiloxane with a specific epoxy resin, and the polysiloxane is represented by the following general formula (2). An organopolysiloxane having a polysiloxane skeleton is used. That is, this organopolysiloxane is the same as the organopolysiloxane used as the C component.

On the other hand, as a specific epoxy resin that is another component of the above-mentioned components, the following general formula (3)
The reason why the number p of repeating units is limited to 0 to 15 is as follows. That is, if the number of repeating units is more than 15, the resulting cured epoxy resin composition will have poor heat resistance.The number p of repeating units is particularly preferably 0 to 5. The epoxy resin is Epicoat 8 manufactured by Yuka Shell Epoxy Co., Ltd.
28. Examples include Epicote toot and Epicote 1004.

The mixing ratio of the organopolysiloxane and the epoxy resin when the above specific organopolysiloxane and the specific epoxy resin are subjected to an addition reaction is determined by the carboxylic acid equivalent (a) in the organopolysiloxane and the epoxy equivalent (b) in the epoxy resin. ) is preferably set so that the equivalent ratio (a)/(b) is from 3/1 to 1/3. That is, outside this range, a large amount of unreacted organopolysiloxane or epoxy resin will remain after the completion of the addition reaction.
This is because the heat resistance of the resulting cured epoxy resin composition tends to decrease.

Note that a tertiary amine catalyst or the like can also be used to promote the above addition reaction. Examples of the above-mentioned tertiary amine catalyst include N,N''-dimethylpiperazine, 1.
4-diaza-bicyclo(2°2.2)octane (triethylenediamine), pyridine, picoline, 1,8-diaza-bicyclo(5,4,0)undecene-7, benzyldimethylamine, 2-methylimidazole, etc. I can give it to you.

Since the above-mentioned components C and D have good dispersibility in the cured epoxy resin composition, the variation in mechanical strength is smaller than that of conventional products, and a low stress effect is exhibited.

Furthermore, since the skeletons of the organopolysiloxane and epoxy resin used both have excellent heat resistance, the heat resistance reliability is also high. Therefore, as will be described later, the moisture resistance reliability and heat resistance reliability of the semiconductor device obtained are ensured.

These addition reaction products of component C and component D may be used alone or in combination.

In addition, in this invention, the above-mentioned A component, B component, C component, D
In addition to the ingredients, a curing accelerator, an inorganic filler, a mold release agent, etc. can be used as necessary. As the curing accelerator, any catalyst for the curing reaction of the phenol-cured epoxy resin can be used; for example, 2.4.6-tri
Examples include tertiary amines such as (dimethylaminomethyl)phenol and 2-methylimidazole. As the filler, silica powder, alumina, calcium carbonate, quartz gas powder, silica powder, talc, clay, zirconium oxide, zirconium silicate, beryllium oxide, 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, and waxes such as carbana wax and montan wax are used. be able to.

Furthermore, commonly used additives such as coupling agents, flame retardants, and colorants can be added.

The epoxy resin composition used in this invention can be manufactured using the above raw materials, for example, in the following manner.

That is, first, an epoxy resin (component A), a novolac type phenolic resin (component B), a specific organopolysiloxane, or an addition reaction product of a specific organopolysiloxane and an epoxy resin (one or both of components C and D). , inorganic fillers and other additives are suitably blended, and this blend is kneaded in a heated state using a kneading machine such as a mixing roll machine to obtain a semi-cured resin composition. After cooling this to room temperature, it is mixed with a known method. The desired epoxy resin composition can be obtained through a series of steps of pulverizing by a means and tableting if necessary.

At this time, the blending amount of the C component and D component is 3 to 40 parts by weight per 100 parts by weight (hereinafter abbreviated as "parts") of the epoxy resin.
It is preferred that the inorganic filler be used in an amount of 30 to 90% by weight based on the entire epoxy resin composition.

In addition, in the method for manufacturing the epoxy resin composition described above, components C and D are blended together with other raw materials. Component B) may be modified and then blended with other raw materials.

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 thus obtained has extremely low stress properties, excellent heat resistance, and excellent moisture resistance. This is 5i-0- derived from organopolysiloxane in component C and component D.
The Si bonding moiety is introduced into the molecular skeleton of the cured resin, and due to the above-mentioned characteristics of the organopolysiloxane and the epoxy resin that undergoes an addition reaction thereto, variations in mechanical strength of the cured epoxy resin composition can be avoided. This is thought to be due to the fact that it becomes smaller.

〔Effect of the invention〕

As described above, the semiconductor device of the present invention has a special epoxy resin composition containing a specific organopolysiloxane or an addition reaction product between a specific organopolysiloxane and an epoxy resin (one or both of the C component and the D component). Because the sealed plastic package is different from conventional epoxy resin compositions, it has high moisture-resistance reliability, high heat-resistance reliability, low internal stress, and high reliability. In particular, by sealing with the special epoxy resin composition mentioned above, it is fully compatible with the sealing of VLSI etc., and the device size is 16 mm.
``As described above, high reliability as described above can be obtained in a special semiconductor device in which the width of the A1 wiring on the element is 2 μm or less, and this is a major feature.

Next, examples will be described.

<Preparation of Component C> First, specific organopolysiloxanes a, b, and c shown in Table 1 below were prepared.

Preparation of Component D> First, an organopolysiloxane a similar to the specific organopolysiloxane shown in Table 1 above.

b', c' (corresponding to a, b, c, respectively) and specific epoxy resins d, e shown in Table 2 below were prepared.

(Left below) Next, in a flask equipped with a stirrer, a thermometer, and a reflux condenser, add the above a'' to C°, 1,4-dioxane (solvent), and 2-methyl in the proportions shown in Table 3 below. After adding imidazole (catalyst) and reacting with stirring under heating under reflux for 12 hours, the solvent was distilled off to obtain 8 types of addition reaction products.

(Left below) <Preparation of modified phenolic resin> Component D thus obtained, the above component C, and novolac type phenolic resin (component A) were blended according to Table 4, and the mixture was heated at 175°C for 1 to 5 hours. By stirring, 12 types of modified phenol resins (■ to @) were obtained.

(Left below) [Examples 1 to 12] Modified phenolic resins obtained in this way (■ to @)
and other raw materials were blended according to Table 5, melt-kneaded for 10 minutes using a mixing roll machine (roll temperature 100'cl), cooled and solidified, and then pulverized to obtain the intended powdered epoxy resin composition.

(The following is a blank space) [Comparative Example] Using the raw materials shown in Table 6 below, these raw materials were kneaded for 10 minutes with a mixing roll machine, and the obtained sheet composition was used in the same manner as Examples 1 to 12. A powdered epoxy resin composition was obtained.

*1: Same as in Table 5 *2: Same as in Table 4 A semiconductor device was manufactured by molding a semiconductor element by transfer molding using the powdered epoxy resin composition obtained in the above Examples and Comparative Examples. Obtained. Regarding the semiconductor device obtained in this way, the bending elastic modulus,
Glass transition temperature, 1000 hour test using a pressure cooker under voltage application (hereinafter referred to as rPCBT test) and -50°C/30 minutes to 150°C/30 minutes
A temperature cycle test (hereinafter abbreviated as "rTCT test") of 200 minutes was conducted. The results are shown in Table 7 below. Note that the glass transition temperature (Tg) is the temperature at which the peak of Tan δ, which is a viscoelastic property, is reached.

(Left below) From the results in Table 7, it can be seen that the Example product has superior low stress properties compared to the Comparative Example product, has excellent results in the PCBT test and TCT test, and has excellent moisture resistance and heat resistance. It can be seen that

Claims (1)

[Claims] (1) A semiconductor element is encapsulated using an epoxy resin composition containing the following components (A) and (B) and further containing at least one of the following components (C) and (D). A semiconductor device. (A) Epoxy resin. (B) Novolac type phenolic resin. (C) Organopolysiloxane represented by the following formula (1). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) [In the above formula (1), R_1 is a divalent organic group, R_
2 represents an alkyl group or a phenyl group having 3 or less carbon atoms, and may be the same or different. n is 5~
It is an integer of 200. ] (D) An addition reaction product of an organopolysiloxane represented by the following formula (2) and an epoxy resin represented by the following formula (3). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(2) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(3) [In the above formulas (2) and (3), R_3 is a divalent organic The group R_4 is an alkyl group or a phenyl group having 3 or less carbon atoms, and may be the same or different. R_5 is hydrogen or a methyl group, and may be the same or different. m is an integer from 5 to 200, p is 0
Or it is an integer from 1 to 15. ]