JPS63299150A - Semiconductor device - Google Patents

Abstract

PURPOSE:To perform a reduction in the stress of a sealing resin, further improving its moisture resistance and reliability, by covering the surface of silica with a covering layer mainly containing specific silicon and epoxy resin to form a silicone modified silica, and using it. CONSTITUTION:Silicone modified silica composed of epoxy resin, phenol resin, and silica, organopolysiloxane having at least one primary or secondary amino group in a molecule, and epoxy compound represented by general formula (I) or (II) is used as a material. A semiconductor element is sealed with the epoxy resin composition containing these components. Its internal stress can be reduce by this sealing, its moisture resistance can be largely improved, and reliability can be remarkably enhanced. However, in the formulas (I), (II), R1, R3 are 12 or less C alkylene group, R2 is alkyl group or aryl group, l is 0 or 1, and m, n are integers of 2 or larger.

Description

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

[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 permeability, so it is resistant to temperature and humidity 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. Such epoxy resin compositions are particularly composed of an epoxy resin, a novolac type phenol resin as a hardening agent, and silica powder as a hardening accelerator and inorganic filler. It is known for its excellent workability (especially moldability during transfer molding operations).

[Problem that the invention seeks to solve]

However, in recent years, due to technological innovation in the semiconductor field, the degree of integration has increased, element sizes have become larger, and interconnections have become finer. internal stress, moisture resistance reliability,
There is a strong demand for improved reliability (shock resistance, heat resistance, etc.), and in particular, there is a strong demand for resins for semiconductor encapsulation to have a property that the stress applied to semiconductor elements is small even when directly molded. The main components of the resin for semiconductor encapsulation are epoxy resin, novolac type phenolic resin, and inorganic filler, as well as a colorant with no curing accelerator.

An epoxy resin composition containing a mold release agent is coated.

However, when molding semiconductor elements with this type of encapsulating resin, the resin
Stress caused by shrinkage after molding may cause cracks in the passivation film of the device or the device itself.
It has become clear that misalignment occurs in 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, in the case of an epoxy resin composition using a phenol resin as a curing agent, the glass transition point of the cured resin is lowered and the high-temperature electrical properties are lowered, so there is a problem in terms of reliability. It is also possible to reduce the stress applied to the element by adding synthetic rubber, etc., but adding synthetic rubber reduces the adhesion of the resin composition to the semiconductor element and lead frame. However, moisture resistance deteriorates and reliability decreases.

1. .

As mentioned above, conventional sealing resins are not quite satisfactory in terms of stress on semiconductor elements.
In order to cope with the increase in element size caused by the above-mentioned technological innovations, further improvement in characteristics is strongly desired.

The present invention was made in view of the above circumstances, and an object of the present invention is to reduce the stress of the sealing resin while further improving the moisture resistance reliability.

[Means for solving problems]

In order to achieve the above object, the semiconductor device of the present invention includes:
The structure is such that a semiconductor element is sealed using an epoxy resin composition containing the following components (A), (B), and (C).

(A) Epoxy resin.

(B) Phenol resin.

(C) Silica, an organopolysiloxane having a small number (one primary or secondary amino group in the molecule), and an epoxy compound represented by the following general formula [I] or [II]. Silicone-modified silica composed of compounds.

That is, the present inventors have conducted a series of studies in order to reduce the stress of the cured epoxy resin composition that becomes the sealing resin while improving the moisture resistance reliability. A specific organoborisiloxane (silicone) is reacted with a specific epoxy compound represented by the above formula (1) or (IF), and the surface of the silica is coated with a coating layer mainly containing the above silicone or epoxy compound. The inventors have discovered that by using silicone-modified silica, the resulting cured epoxy resin composition has excellent low stress properties and also has improved moisture resistance, and has thus arrived at this invention. did.

The epoxy resin composition used in this invention is obtained by using the epoxy resin (A) component, the phenol resin (B) component, and the silicone-modified silica (C) component, as described above, It is usually in the form of powder or compressed tablets.

The epoxy resin serving as the above A component is not particularly limited, and various epoxy resins conventionally used as encapsulating resins for semiconductor devices can be mentioned, such as Talesol novolac type, phenol novolac type, and bisphenol A type. . Among these resins, it is best to use one with a melting point above room temperature and a solid or highly viscous solution at room temperature. Phenol novolac type epoxy resins usually have an epoxy equivalent. 160-250. Those having a softening point of 50 to 130°C are used, and as Talesol novolak type epoxy resins, those having an epoxy equivalent of 180 to 210° and a softening point of 60 to 110°C are generally used.

The phenol resin of component B used together with the above epoxy resin acts as a curing agent for the above epoxy resin, and includes phenol novolac, 0-talesol novolak, m-talesol novolak, p-talesol novolak, 0- Ethylphenol novolak, m-ethylphenol novolak, p-ethylphenol novolak, etc. are preferably used. These novolak resins are
Softening point: 50-110°C, hydroxyl equivalent: 100-150
It is preferable to use one.

Component C used together with component A and component B is silicone-modified silica, which is obtained using silica, a specific organopolysiloxane, and an epoxy compound represented by the general formula (I) or (n).

The above-mentioned silica refers to crystalline silica (crystalline silica) and amorphous silica (fused silica).Such silica preferably contains few electrolyte impurities and foreign substances.

Further, the above-mentioned specific organopolysiloxane is an organopolysiloxane having at least one primary or secondary amino group in the molecule, for example, the organopolysiloxane schematically represented by the following formula (a). Examples include those in which both ends of the molecular chain are primary amino groups, as in This can be done.

These organopolysiloxanes have different molecular weights.

A wide variety of commonly used materials can be used regardless of viscosity and the like. As an example, the following general formula (
The following can be mentioned.

In addition, a pendant type polydimethylsiloxane oligomer in which the methyl groups of the oligomer are partially substituted with the following substituents is also suitable.

[However, x/y 3/1 to 500/1) Furthermore, the 1ζoxy compound used with the above specific organopolysiloxane is one represented by the above general formula [■] or (n). be. The epoxy compound represented by the general formula [1] desirably has a molecular weight of 200 to 10,000, particularly preferably one having a molecular weight of about 200 to 5,000. Representative examples of this specific epoxy compound include polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and the like. Furthermore, the epoxy compound represented by general formula (II) is
It is desirable to have a molecular weight of 150 to 10,000, and it is especially preferable to use one with a molecular weight of about 150 to 5,000. Representative examples of this specific epoxy compound include polyethylene glycol glycidylphenyl ether, polypropylene glycol glycidylphenyl ether, and the like.

The silicone-modified silica as component C used in this invention can be produced using the above-mentioned raw materials in the following manner. That is, the three components of silica, organopolysiloxane, and epoxy compound are mixed and heated to react.
It can be manufactured by coating the silica surface with a coating layer mainly made of silicone or epoxy compounds. In addition, the heating conditions in the above synthesis reaction are a temperature of 50 to 20
It is about 0.1 to 12 hours at 0°C for 1 hour. Further, the mutual usage ratio of the organopolysiloxane and the epoxy compound is such that the number of hydrogen atoms of the amino group in the organopolysiloxane is 0.1 to 10 per 1 epoxy group in the epoxy compound. It is preferable to set the total amount of the epoxy compound and organopolysiloxane to be 1/100 to 20/2 of the weight of the silica.
Good results can be obtained by setting the amount within the range of 100. In other words, if the total amount is outside the above range, a satisfactory low stress effect may not be obtained, or the moisture resistance reliability and electrical properties of the semiconductor device may be affected. This is because the phenomenon of deterioration of characteristics etc. is observed.

By modifying silica with the above-mentioned raw materials, the silica is coated with a coating layer mainly composed of silicone and epoxy compounds, and the silica itself has rubber elasticity. Therefore, by using silicone-modified low-stress silica with such characteristics as a filler, it is possible to reduce the stress of the cured epoxy resin composition and at the same time achieve excellent moisture resistance reliability. Become. In this case, there is no problem in using the above silicone-modified silica and unmodified normal silica together.
When used together in this way, it is preferable to set the modified silica so that it occupies 50% or more of the total silica from the viewpoint of effectiveness.

In addition to the above-mentioned raw materials, a curing accelerator, a mold release agent, etc. can be used in the epoxy resin composition used in the present invention, if necessary. As the curing accelerator, any catalyst for the curing reaction in the phenol-cured epoxy resin can be used, such as tertiary amines, imidazoles, phosphorus compounds, and the like. As mold release agents, conventionally known long chain carboxylic acids such as stearic acid 5-palmitic acid, metal salts of long chain carboxylic acids such as zinc stearate and calcium stearate, carnauba wax,
Montan waxes and the like can be used. moreover,
Commonly used additives such as flame retardants 9 and colorants can also be added.

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

That is, epoxy resin (component A), phenol resin (
Component B), silicone-modified silica (component C), and other additives are appropriately blended, and this mixture is kneaded under heating in a mixer such as a mixing roll machine to form a semi-cured resin composition. An epoxy resin composition can be produced through a series of steps of cooling to room temperature, pulverizing by known means, and, if necessary, tableting.

The encapsulation 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 excellent low stress properties and high moisture resistance reliability.

〔Effect of the invention〕

The semiconductor device of the present invention is encapsulated using an epoxy resin composition containing special silicone-modified silica that itself has rubber elasticity, and the encapsulated plastic package is a conventional epoxy resin composition. Because it is different from the previous one, it has low internal stress and greatly improved moisture resistance, making it extremely reliable. By using such a special epoxy resin composition, it becomes possible to obtain the above-mentioned high reliability in a large semiconductor device with a chip having a long side of 4 fi or more, and this is a major feature.

Next, the present invention will be explained in detail based on examples.

〔Example〕

First, silicone-modified silica was prepared as follows.

[Preparation of silicone-modified silica]

To 100 parts by weight of fused silica (hereinafter abbreviated as "parts"), (a) X parts of an organopolysiloxane shown in Table 1 below was added, and at the same time (b) Y parts of an epoxy compound were added.
Silicone-modified silica was prepared by heating and mixing at 50° C. for 2 hours, followed by cooling and pulverization.

(Left below) Next, the silicone-modified silica obtained as above and other raw materials were blended in the proportions shown in Table 2 below, and melt-kneaded for 10 minutes using a mixing roll machine (roll temperature 100°C). The mixture was then cooled and solidified, and then pulverized to obtain the desired powdered epoxy resin composition.

(The following is a blank space) [Comparative Example] Using the raw materials shown in Table 3 below, these raw materials were kneaded for 10 minutes using a mixing roll machine, then cooled and solidified, and then pulverized to produce a powdered epoxy resin in the same manner as in the example. A composition was obtained.

(Margin below) Saiko said the flute and got a reaction generation theft.

Using the powdered epoxy resin compositions obtained in the above Examples and Comparative Examples, test samples were prepared by transfer molding, and tests as shown in Table 4 below were conducted on the obtained test samples. The results were as shown in Table 4.

(Left below) From the results in Table 4, it can be seen that the specific product has low stress and excellent moisture resistance as a sealing resin, and therefore, semiconductor devices using it have excellent reliability. You can see that it will become like this.

Claims (1)

[Claims] (1) A semiconductor device in which a semiconductor element is sealed using an epoxy resin composition containing the following components (A), (B), and (C). (A) Epoxy resin. (B) Phenol resin. (C) Comprised of silica, an organopolysiloxane having at least one primary or secondary amino group in the molecule, and an epoxy compound represented by the following general formula [I] or [II]. silicone-modified silica. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[II] In [formulas [I] and [II], R_1 and R_3 are alkylene with 12 or less carbon atoms. The group R_2 is an alkyl group or an aryl group, l is 0 or 1, and m and n are integers of 2 or more. ]