JP2534317B2 - Semiconductor device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly reliable semiconductor device.

[Conventional technology]

Semiconductor elements such as transistors, ICs, and LSIs are usually sealed with a ceramic package or a plastic package to form a semiconductor device. In the above ceramic package, the constituent material itself has heat resistance and excellent moisture permeation resistance, so that 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 inferior, the resin sealing using the plastic package has recently become the mainstream. An epoxy resin composition has been conventionally used for this type of resin encapsulation, and has achieved good results.

As the epoxy resin composition, in particular, an epoxy resin, and a novolak type phenol resin as a curing agent,
A material composed of a system such as a silica powder as a curing accelerator and an inorganic filler is praised for its excellent sealing workability (particularly, moldability during transfer molding work).

[Problems to be solved by the invention]

However, recently, technological innovation in the semiconductor field has led to an increase in the degree of integration as well as an increase in the size of elements and miniaturization of wirings. Improvement of internal stress, moisture resistance reliability, impact resistance reliability, heat resistance reliability, etc.) of a semiconductor device has been demanded. When a semiconductor element is molded with the above epoxy resin composition, a resin which has hardly been a problem in the past has been obtained. It has been known that the stress causes a resin crack, a crack on the passivation film and the element itself, and a shift in the aluminum wiring. This becomes more remarkable as the size of the element itself increases. Therefore,
Nowadays, as a countermeasure against this, the development of a resin (low-stress resin) with a small stress applied to an element or the like is a major issue. As a method for achieving this purpose, it is considered that the epoxy resin or the phenol resin itself is made flexible or a plasticizer is added. However, doing so has a problem in reliability since the glass transition point of the cured resin is lowered and the high temperature electrical characteristics are lowered in the epoxy resin composition using the phenol resin as a curing agent. It is also possible to reduce the stress applied to the element by adding synthetic rubber etc. to reduce the stress, but by adding synthetic rubber, the sealing resin can be adhered to the semiconductor element and the lead frame. However, there is a problem that the reliability is deteriorated, the moisture resistance is deteriorated, and the reliability is deteriorated.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a semiconductor device having excellent internal stress characteristics without deteriorating other reliability.

[Means for solving problems]

In order to achieve the above object, the semiconductor device of the present invention has a structure in which a semiconductor element is sealed with an epoxy resin composition containing the following components (A) to (C).

(A) Epoxy resin.

(B) Novolac-type phenol resin.

(C) An organopolysiloxane represented by the following general formula (I).

[Operation] That is, the present inventors have confirmed that other reliability (moisture resistance reliability,
A series of studies have been conducted with the aim of realizing a stress reduction of the encapsulating resin without impairing the impact resistance and heat resistance). As a result, they have found that the use of the organopolysiloxane having the above-mentioned characteristics makes it possible to reduce the stress of the sealing resin without impairing other reliability, and has reached the present invention.

The epoxy resin composition used in the present invention comprises an epoxy resin (component A) and a novolak type phenol resin (component B).
And a specific organopolysiloxane (C component) and the like, and is usually in the form of powder or a tablet formed by compressing it.

The epoxy resin as the component A is not particularly limited, and various epoxy resins such as cresol novolak type, phenol novolak type, and bisphenol A type that have been conventionally used as sealing resins for semiconductor devices can be used. can give. Among these resins, those having a melting point over room temperature and exhibiting a solid state or a high-viscosity solution state at room temperature bring about good results. Further, as a novolak type epoxy resin, an epoxy equivalent of 16 is usually used.
A cresol novolak type epoxy resin having an epoxy equivalent of 180 is used.
Those having a softening point of ~ 210 and a softening point of 160 to 110 ° C are generally used.

The novolak-type phenol resin of the B component used together with the epoxy resin of the A component acts as a curing agent for the epoxy resin, and includes phenol novolak, o-cresol novolak, m-cresol novolak, p- Cresol novolak, o-ethylphenol novolak, m-ethylphenol novolak, p-ethylphenol novolak and the like are preferably used. These novolak resins have a softening point of 50 to 110 ° C and a hydroxyl equivalent of 100 to 15
It is preferable to use 0.

As the organopolysiloxane of the C component used together with the epoxy resin of the A component and the novolak type phenol resin of the B component, those having the polysiloxane skeleton represented by the general formula (I) are used, and the siloxane bond part is The feature is that a phenyl group or an aralkyl group is bonded. In addition, among the above organopolysiloxanes, it is particularly preferable to use a compound in which R ₂ which is a divalent organic group is an alkylene group having 2 to 10 carbon atoms, a phenylene group, or an aralkylene group having 7 to 15 carbon atoms. preferable. Such an organopolysiloxane has a molecular weight of 500 to 40,000.
It is preferable to use one having a molecular weight of
It is from 5,000 to 30,000. That is, if the molecular weight is less than 500, the low stress effect of the encapsulating resin is insufficient, and if it exceeds 40,000, the reactivity with the epoxy resin of the component A tends to deteriorate.

Since the C component has good dispersibility in the cured product of the epoxy resin composition, the cured product has extremely small variation in mechanical strength as compared with the conventional one, and has low stress.

In the present invention, a curing accelerator, an inorganic filler, a release agent and the like can be used in addition to the above-mentioned components A, B and C, if necessary.

As the above-mentioned curing accelerator, any one that serves as a catalyst for the curing reaction in the phenol-cured epoxy resin can be used, and examples thereof include tertiary amines, imidazoles, phosphorus compounds and the like.

As the filler, powders of silica, alumina, calcium carbonate, quartz glass, silica stone, talc, clay, zirconium oxide, zirconium silicate, beryllium oxide and the like can be used.

As the 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, waxes such as carbanawax and montan wax are used. be able to.

Further, commonly used additives such as coupling agents, flame retardants, coloring agents and the like can be added.

The epoxy resin composition used in the present invention can be manufactured using the above-mentioned raw materials, for example, as follows.
That is, first, an epoxy resin (component A), a novolak type phenol resin (component B), a specific organopolysiloxane (component C), an inorganic filler and other additives are appropriately mixed, and this mixture is mixed with a mixing roll machine. A kneading machine such as a kneader to knead in a heated state to obtain a semi-cured resin composition, which is cooled to room temperature and then crushed by a known means, and a series of steps of tableting as necessary to achieve the purpose. It is possible to obtain an epoxy resin composition. Further, the specific organopolysiloxane (component C) and the epoxy resin (component A) are reacted in advance by a known method, for example, by melting or heating in a solvent to cause the above two components to react with each other, and the reaction product and other components. An epoxy resin composition can be obtained by using the raw materials and following the same production method as above.

At this time, the compounding amount of the organopolysiloxane (C component) is 3 to 40 parts with respect to 100 parts by weight of the epoxy resin (hereinafter abbreviated as “part”) so that the obtained resin cured product has low stress From the point of view, the content of the inorganic filler is 30 to 30 with respect to the entire epoxy resin composition.
It is preferably 90% by weight.

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

The semiconductor device thus obtained has excellent low stress properties and high reliability. This is because the Si-O-Si bond portion derived from the organopolysiloxane in the C component is introduced into the molecular skeleton of the cured resin, and the dispersibility of the organopolysiloxane in the epoxy resin is excellent. Therefore, it is considered that variations in the mechanical strength of the sealing resin made of the cured epoxy resin composition are reduced.

〔The invention's effect〕

As described above, the semiconductor device of the present invention is sealed by using a special epoxy resin composition containing a specific organopolysiloxane (C component), and the sealing plastic package has a conventional epoxy resin composition. Since it is different from a product, it has low internal stress and high reliability. In particular, the encapsulation with the above-mentioned special epoxy resin composition is sufficient for encapsulation of VLSI, etc., and the element size is 16 m.
In a special semiconductor device in which the width of Al wiring on the element is 2 μm or less and m ² or more, the high reliability as described above can be obtained, which is a major feature.

 Next, examples will be described together with comparative examples.

[Examples 1 to 6 and Comparative Example 1] Organopolysiloxanes shown in Table 1 below were prepared. Next, the raw materials in the proportions shown in Table 2 below are used, and these raw materials are mixed in a mixing roll machine (roll temperature 10
The mixture was melt-kneaded at 0 ° C. for 10 minutes, cooled and pulverized to obtain the target powdery epoxy resin composition.

Comparative Example 2 The raw materials shown in Table 3 below were used. Otherwise in the same manner as in Examples 1 to 6, powdery epoxy resin compositions were obtained.

A semiconductor device was obtained by molding a semiconductor element by transfer molding using the powdery epoxy resin composition obtained in the above Examples and Comparative Examples. The semiconductor device thus obtained was subjected to measurements such as bending elastic modulus, bending strength, and a temperature cycle test (hereinafter abbreviated as “TCT test”) of −50 ° C./5 minutes to 150 ° C./5 minutes. The results are shown in Table 4 below. The glass transition temperature (Tg) is the temperature of the Tan δ peak of the viscoelastic property.

From the results shown in Table 4, the products of Examples had a small flexural modulus (soft) of the encapsulating resin and a small internal stress, and the flexural strength did not decrease so much as compared with the Comparative Example, and the glass transition temperature decreased. It can be seen that it has a high degree of reliability as can be seen from the results of the TCT test.

Claims (1)

(57) [Claims] 1. A semiconductor device obtained by encapsulating a semiconductor element with an epoxy resin composition containing the following components (A) to (C). (A) Epoxy resin. (B) Novolak type phenolic resin. (C) An organopolysiloxane represented by the following general formula (I).