JPH0320065A - Semiconductor device - Google Patents

Abstract

PURPOSE:To make it excellent in heat resistance reliability and moisture resistance reliability by sealing it with an epoxy resin composition which contains specific quaternary phosphonium. CONSTITUTION:A semiconductor element is sealed using an epoxy resin composition which contains each component of epoxy resin, phenol resin, quaternary phosphonium salt of divalent or more carboxylic acid, boric acid, and ester of boric acid compound. That is, it is effective to use specific quaternary phosphonium salt as a hardening accelerator, and by using one party or both parties of boric acid and ester of boric acid compound together with those components, the moisture resistance improves further. Hereby, a semiconductor device excellent in heat resistance and moisture resistance reliability can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device having excellent heat resistance and moisture resistance reliability.

[Conventional technology]

Semiconductor elements such as transistors, ICs, and LSIs are usually sealed in ceramic packages or plastic packages to form semiconductor devices. In the above ceramic package, the material itself has heat resistance,
It also has excellent moisture permeability, allowing for highly reliable sealing that is strong against temperature and humidity. However, recently, resin sealing using the above-mentioned plastic package has become mainstream because the construction material is relatively expensive and it is not suitable for mass production. Furthermore, epoxy resin compositions have traditionally been used in this type of brass packaging material. The above epoxy resin composition is
Due to its excellent electrical properties, mechanical properties, chemical resistance, etc.
It is highly reliable and widely used for resin sealing of semiconductor devices. And, as such an epoxy resin composition,
An epoxy resin, a novolak type phenol resin which is a hardening agent for the epoxy resin, a hardening accelerator, an inorganic filler, etc. It has been awarded for its excellent qualities such as gender.

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 getting smaller, packages are becoming smaller and thinner, and along with this, there is a demand for even greater reliability in encapsulation materials. [Problems to be solved by the invention] In other words, semiconductor devices encapsulated with conventional epoxy resin compositions have poor heat resistance and moisture resistance at the currently required level of reliability. In particular, when moisture resistance deteriorates, defects occur mainly due to corrosion of aluminum electrodes, wiring, etc. on the device.

The present invention was made in view of the above circumstances, and an object thereof is to provide a semiconductor device having excellent heat resistance reliability and humidity resistance reliability.

[Means for solving problems]

In order to achieve the above object, the semiconductor device of the present invention includes:
(A) below. (B), (C) components and optionally (
D) The method is to encapsulate the semiconductor element using an epoxy resin composition containing the precepts. (.A) Epoxy resin.

(B) Phenol resin.

(C) Quaternary phosphonium salt of divalent or higher carboxylic acid.

CD) At least one of boric acid and a boric acid ester compound.

[Effect]

That is, the present inventors have conducted a series of studies with the aim of improving the heat resistance and moisture resistance of the sealing resin made of the above-mentioned epoxy resin composition.

As a result, it was found that it is effective to use a specific quaternary phosphonium salt of c4 as a curing accelerator in order to improve the heat resistance and moisture resistance. As a result of further research, it was discovered that moisture resistance was further improved by using one or both of the boric acid and boric acid ester compounds of the D precept together with the C component, resulting in the present invention.

Epoxy resin used in this invention! j! The precept uses epoxy resin (Atc component), phenol resin (B precept), and a specific quaternary phosphonium salt (C component), and in some cases, boric acid and boric acid ester together with the above A-C precepts. It is obtained by using one or both of the compounds (D-compound), and is usually in the form of a powder or a tablet made by compressing it.

The epoxy resin of the above A component is not particularly limited, and examples include bisphenol A type epoxy resin, novolac type epoxy resin synthesized from various phenols, etc., which have been conventionally used as encapsulating resins for semiconductor devices. Various epoxy resins are used. Among these resins, it is best to use resins that have a melting point above room temperature and are solid at room temperature. especially,
Novolak type epoxy resins are preferred, and among them, those with an epoxy molar ratio of 160 to 250 and a softening point of 50 to 130''C are preferably used.In addition, these epoxy resins contain ionic impurities and are easily hydrolyzed into ions. The fewer the components, the more preferable it is. Specifically, it is preferable that the concentration of free sodium ions and chlorine ions is 5 ppm or less, and the concentration of hydrolyzable chlorine ions is 600 ppn+ or less.

The B phenolic resin used together with the Atc epoxy resin acts as a curing agent for the epoxy resin, and includes, for example, phenol novolak resin.
Talesol novolak resin. Examples include novolac type phenolic resins such as tert-butylphenol novolak resin and nonylphenol novolac resin, resol type phenolic resins, and polyoxystyrenes such as polyvaroxystyrene. Among these, novolac type phenolic resins are particularly preferred. As these novolac type phenolic resins, those having a softening point of 50 to 110'C and a hydroxyl equivalent of 100 to 150 are preferably used.

These phenol resins as component B may be used alone or in combination.

The blending ratio of the epoxy resin of the above precept A and the phenol resin of the B component should be such that the hydroxyl group in the phenol resin is 0.5 to 2.0 equivalent per 1 equivalent of epoxy group in the epoxy resin. is suitable. That is, if it is outside the above range, it will be difficult to obtain a sufficient curing reaction, and the properties of the cured product of the epoxy resin composition will tend to deteriorate.

The specific quaternary phosphonium salt of component C used with the epoxy resin of component A and the phenol resin of component B acts as a curing accelerator,
A quaternary phosphonium salt of divalent or higher carboxylic acid is used.

For example, maleic acid. Adivic acid, phthalic acid. Tetrahydrophthalic acid, Hexahydrophthalic acid, Trimellitic acid,
Examples include tetraphenylphosphonium salts, tetra-n-butylphosphonium salts, and ethyltriphenylphosphonium salts of polycarboxylic acids such as pyromellitic acid. The amount of the specific quaternary phosphonium salt for the above CTC is the sum of the epoxy resin for the A component and the phenol resin for the B component.
iloo parts by weight (hereinafter abbreviated as "parts"): 0. l~
It is preferable to set the ratio to 5 parts, more preferably 0 parts.
．． 5 to 3 parts. That is, if the amount of the specific quaternary phosphonium salt of component C is 0. If it is less than 1 part, a sufficient curing accelerating effect will not be observed, and if it exceeds 5 parts, the moldability will deteriorate.
This is because there is a decrease in moisture resistance. Furthermore, by using one or both of the boric acid and boric acid ester compounds of component D, a synergistic effect with the quaternary phosphonium salt of component C is brought about, further improving moisture resistance.

Examples of the boric acid mentioned above include orthoboric acid, metaboric acid, and tetraboric acid. In addition, the boric acid ester compounds include monoboric acid ester compounds having one boron atom in one molecule and two or more boron atoms in one molecule represented by the following general formulas ([) to (III). Examples include polyboric acid ester compounds having atoms.

B (OR) 3 (1) Examples of such boric acid ester compounds include trimethyl borate, triethyl borate. Triisoprobyl borate. Triptyl borate. Tricyclohexyl borate, triphenyl borate, tricresyl borate. Trinonylphenyl borate, trinaphthyl borate. Examples include tribenzyl borate, butyl polyborate, phenyl polyborate, cresyl polyborate, and benzyl polyborate. The blending amount of at least one of the boric acid and boric acid ester compounds of the D precept is 0.000 parts per 100 parts of the total fi of the epoxy resin for A) 3i and the phenol resin for the B precept. It is preferable to set the ratio to the ot-to portion,
Particularly preferably 0.05 to 5 parts.

In addition, epoxy resin tiIII used in this invention
i. In addition to the above A-D precepts, the product may be surface treated with inorganic fillers, mold release agents, halogen compounds, flame retardants such as antimony dioxide, pigments and dyes such as carbon black, silane coupling agents, etc., as necessary. or other stress-reducing agents can be used as appropriate. The above-mentioned inorganic filler is preferably blended when a transfer or molding method is used for resin encapsulation of semiconductor elements, such as silica powder. Aluminum powder talc. clay. Examples include glass fiber.

In particular, among these, meltable or crystalline silica powder is preferably used. The blending amount of the above inorganic filler varies depending on the epoxy resin as the A component, the phenol resin as the B component, and the type of inorganic filler, but the total amount of the epoxy resin as the A component and the phenol resin as the B component is 10
It is preferable to set the ratio to 150 to 600 parts to 0 parts.

Further, examples of the above-mentioned mold release agent include natural waxes, Gakai waxes, metal salts of long-chain fatty acids, acid amides, esters, and baraffins.

The epoxy resin composite used in the present invention can be produced, for example, as follows.

That is, the epoxy resin of component A and the BTIi. A phenol resin and a specific quaternary phosphonium salt of C are combined with one or both of boric acid and boric acid ester compounds of D, and if necessary, an inorganic filler, M
Manufactured by a series of steps in which molding agents and other additives are sufficiently mixed, for example, in a mixer, then melt-mixed using a hot roll machine or mixed using a double-dagger, and then compressed into tablets if necessary. can do.

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

The semiconductor device obtained in this way has a specific quaternary phosphonium salt (component C) contained in the epoxy resin compound.
Due to this action, it has extremely excellent heat resistance reliability and moisture resistance reliability, and furthermore, by using one or both of boric acid and a boric acid ester compound (component D), it has even more excellent moisture resistance reliability.

[Effects of the Invention] As described above, the semiconductor device of the present invention is sealed with an epoxy resin composition containing the specific quaternary phosphonium salt of the C precept, and the sealing resin is heat-resistant. Excellent heat resistance and reliability due to its high heat resistance and moisture resistance. It has moisture resistance and reliability. Further, when one or both of the boric acid and boric acid ester compounds of the D precept are used, the moisture resistance reliability becomes even more excellent due to the synergistic effect with the specific quaternary phosphonium salt of the C component.

Next, examples will be described together with comparative examples.

First, prior to the examples, Or1 was prepared according to the following manufacturing method.
- A melt mixture powder containing boric acid and a melt mixture powder containing triphenyl borate were produced.

<Preparation of molten mixture powder containing orthoboric acid> 400 g of phenol novolac resin with a softening point of 80°C and 6 g of orthoboric acid are mixed, and this is heated to 140 to 160°C to melt and form a uniform molten mixture. Created. Furthermore, the above molten mixture is cooled and then pulverized to form a molten mixture powder containing orthoboric acid (hereinafter referred to as "powder A").
I got it.

<<Preparation of molten mixture powder containing triphenyl borate>> 50 g of triphenyl borate was used in place of 6 g of orthoboric acid. Other than that, the process was the same as that of the above-mentioned powder A. Melt mixture powder (hereinafter '') containing triphenyl borate was prepared in the same manner as above.
'F5) End B') was obtained.

[Examples 1 to 9, Comparative Examples 1 to 3] The raw materials shown in Table 1 below were blended in the proportions shown in the same table, and this mixture was kneaded for 10 minutes with a heated roll machine (temperature 100 ° C). The mixture was cooled and pulverized to obtain a powdered epoxy resin composition.

(Left below) Next, using the powdered epoxy resin compound obtained in the above examples and comparative examples, a semiconductor element designed to examine corrosion of aluminum metal electrodes was transferred or shaped. Shape condition: Shape temperature 17
A semiconductor device was obtained by molding at 5° C. (molding time: 2 minutes), further shaping, and curing at 175° C. for 5 hours. The moisture resistance characteristics of the semiconductor device thus obtained were measured, and the results are shown in Table 2 below.

In addition, the volume resistivity, mechanical strength, and glass transition temperature of the cured product obtained by molding the obtained epoxy resin composite under certain conditions similar to those described above were measured, and the results are also shown in Table 2. . In addition, the above-mentioned moisture resistance properties were measured as shown below.

<Moisture resistance characteristics> In a pressure cooker atmosphere at a temperature of 130°C and 85% RH, a 20V DC current was applied, and those in which wire breakage occurred due to corrosion of the argonium electrode were judged to be defective (Examples 1 to 4, Comparison) Examples ■~3).

In addition, the cumulative failure rate was investigated when the time of the reliability test under the above-mentioned pressure cracker atmosphere was changed (Example 5).
~9).

(Left below) From the results in Table 2, Comparative Examples 1 and 2 have relatively high glass transition temperatures but poor moisture resistance reliability, and Comparative Example 3 has good moisture resistance reliability but low glass transition temperature. low. On the other hand, the example products have a high glass transition temperature and excellent moisture resistance reliability. From this, it can be seen that the example products are excellent in heat resistance reliability and humidity resistance reliability.

Claims (2)

[Claims] (1) A semiconductor device in which a semiconductor element is encapsulated using an epoxy resin composition containing the following components (A), (B), and (C), and optionally component (D). (A) Epoxy resin. (B) Phenol resin. (C) Quaternary phosphonium salt of divalent or higher carboxylic acid. (D) At least one of boric acid and a boric acid ester compound. (2) An epoxy resin composition for semiconductor encapsulation containing the following components (A), (B), and (C) and optionally component (D). (A) Epoxy resin. (B) Phenol resin. (C) Quaternary phosphonium salt of divalent or higher carboxylic acid. (D) At least one of boric acid and a boric acid ester compound.