JP3982518B2 - Epoxy resin composition for semiconductor encapsulation and semiconductor device using the same - Google Patents

Description

  The present invention relates to a sealing material excellent in flame retardancy, moldability, and reliability, and a semiconductor device using the same.

For the sealing of semiconductor elements, resin sealing is the mainstream in terms of productivity and cost. As the sealing resin, an epoxy resin composition excellent in electrical characteristics, cost, workability and the like is mainly used. However, since an epoxy resin has insufficient flame retardancy, a brominated epoxy resin is usually added to improve the flame retardancy. In addition, antimony compounds (antimony trioxide, antimony pentoxide, etc.) having a synergistic effect with brominated flame retardants are used in combination. In recent years, from the viewpoint of environmental protection, there is an increasing demand for regulations on the use of brominated flame retardants that are suspected of producing dioxins during combustion and antimony compounds that have been pointed out to be carcinogenic.
In response to this requirement, various alternative flame retardants have been investigated. For example, metal hydrates such as aluminum hydroxide and magnesium hydroxide must be added in a large amount in order to exhibit sufficient flame retardancy, leading to deterioration of the curability and strength of the resin composition. End up.
Various products have also been proposed for phosphoric acid ester flame retardants (including those used in combination with nitrogen), but none of them meet the requirements for semiconductor encapsulation applications in terms of moldability and reliability.

  An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation which does not contain a brominated flame retardant or an antimony compound and has excellent moldability, reliability and flame retardancy, and a semiconductor device using the same. .

That is, the present invention relates to a semiconductor that contains zinc molybdate as an essential component as a flame retardant and does not contain a brominated flame retardant and an antimony compound in a sealing material mainly composed of an epoxy resin, a phenol curing agent and an inorganic filler. The present invention relates to an epoxy resin composition for sealing and a semiconductor device using the same.
So far, zinc molybdate has been known as a smoke suppressant such as vinyl chloride. However, these are auxiliary agents for other flame retardants (particularly brominated flame retardants) or smoke suppressants, and no examples of achieving UL94 V-0 with zinc molybdate alone have been reported. As a result of intensive studies, the present inventors have surprisingly found that the epoxy resin composition produced with the above composition achieves UL94 V-0 only by adding a small amount of zinc molybdate as a flame retardant. And completed the present invention. That is, the epoxy resin composition for semiconductor encapsulation of the present invention comprises (A) a biphenyl type epoxy resin, (B) a phenol curing agent, (C) a curing accelerator, (D) an inorganic filler, and (E) an inorganic substance. It is characterized by containing a core of which is coated with zinc molybdate. Details will be described below.

In epoxy resin composition for semiconductor encapsulation mainly composed of epoxy resin, phenol curing agent and inorganic filler, it contains bromine-based flame retardant and antimony compound by blending zinc molybdate as an essential component as flame retardant. Therefore, it is possible to obtain a molding material that satisfies the flame retardancy UL94 V-0, has excellent reliability and moldability, and has a very small influence on the environment.
Further, by sealing a semiconductor element using this molding material, a semiconductor device having excellent reliability and flame retardancy can be obtained.

Although there is no restriction | limiting in particular as an epoxy resin used by this invention, An ortho cresol novolak type, a biphenyl type, a dicyclo type etc. can be used individually or in combination, Especially a biphenyl type is suitable.
Although there is no restriction | limiting in particular as a hardening | curing agent, Although a phenol novolak type, an aralkyl type (paraxylylene modified phenol resin), a terpene type etc. can be used individually or in combination, an aralkyl type is especially suitable.
Although there is no restriction | limiting in particular as a hardening accelerator, Tetraphenylphosphonium-tetraphenyl borate, a triphenylphosphine, the addition product of a triphenylphosphine and a benzoquinone, 1,8-diaza-bicyclo (5,4,0) -undecene -7,2-Phenyl-4methyl-imidazole, triphenylphosphonium-triphenylborane and the like can be used alone or in combination, but an adduct of triphenylphosphine and benzoquinone is particularly preferable.
Although there is no restriction | limiting in particular in a coupling agent, Epoxysilane is used suitably.
The release agent is not particularly limited, and higher fatty acids such as carnauba wax and polyethylene wax can be used alone or in combination, but the combination is particularly preferred.
The inorganic filler is blended in an amount of 70 to 95 wt%, and the filler shape is spherical or crushed, and fused silica, crystalline silica, alumina and the like can be used alone or in combination. In particular, spherical fused silica is preferred.
When the amount of the filler is 70% by weight or less, the flame retardancy is lowered, and when it is 95% by weight or more, there is a problem in fluidity. A range of 85 to 95% by weight is particularly suitable.

As the flame retardant, zinc molybdate is used. Preferably, a core of zinc oxide molybdate coated with a nucleus such as magnesium oxide or silicon oxide is used. The content of zinc molybdate in the resin composition is preferably 0.05 to 10.0% by weight. If it is less than 0.05%, the flame retardancy is insufficient, and if it is more than 10.0%, there is a problem in moldability. In particular, a range of 0.1 to 5.0% is preferably used.
As a flame retardant in which talc is coated with zinc molybdate, KEMGARD911 from SHERWIN-WILLAMS is easily available.

As other additives, a colorant (carbon black, etc.), a modifier (silicone, silicone rubber, etc.), and an ion trapper (hydrotalcite, antimony-bismuth, etc.) can be used.
As a general method for producing a molding material using the raw materials as described above, a raw material mixture having a predetermined blending amount is sufficiently mixed with a mixer or the like, then kneaded with a hot roll or an extruder, cooled and pulverized. By doing so, a molding material can be obtained.
As a method for sealing an electronic component using the epoxy resin composition obtained in the present invention, a low-pressure transfer molding method is the most common, but it can also be performed by methods such as injection molding, compression molding, and casting. is there.
The epoxy resin composition produced by using the above-mentioned means is environmentally friendly because it does not contain brominated flame retardants and antimony compounds, and is excellent in moldability and reliability. For sealing transistors, ICs, LSIs, etc. It can be used suitably.

EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to this.
Examples 1-3, Comparative Examples 1-3
First, various materials shown in Table 1 were used. In Examples 1 to 3 and Comparative Examples 1 to 3, each material was premixed (dry blended), and then for 10 minutes with a biaxial roll (roll surface temperature of about 80 ° C.). It was kneaded and cooled and pulverized.

この封止材を用い、トランスファー成形機を用い、金型温度１８０℃、成形圧力７０ｋｇｆ／ｃｍ、硬化時間９０秒の条件で各試験を行った。
スパイラルフローは、ＥＭＭＩ１−６６により測定した。
熱時硬度はショア硬度計にて測定した。
また、この封止材を用いて、半導体素子をトランスファー成形機で同様の条件で成形しポストキュア（１７５℃／５ｈ）後、耐湿性と半田耐熱性を評価した。
耐湿性に用いた半導体装置は、ＳＯＰ−２８ピンであり、８５℃／８５ＲＨ％７２時間吸湿＋２１５℃／９０秒（ＶＰＳ）の前処理後、ＰＣＴ（１２１℃／２気圧）に放置してＣｈｉｐ上配線の断面の有無を評価した。
半田耐熱性に用いた半導体装置は、ＱＦＰ８０ピンの樹脂封止型半導体装置（外形寸法２０×１４×２．０ｍｍ）であり、リードフレームは４２アロイ材（加工なし）で８×１０ｍｍのチップサイズを有するものである。
このようにして得られた樹脂封止型半導体装置について、半田耐熱性を以下に示す方法で測定した。
１２５℃／２４ｈベーキング後、８５℃／８５％ＲＨで所定の時間吸湿した後、２４０℃／１０ｓｅｃの処理を行った時の樹脂封止型半導体装置のクラック発生率を求めた。
上記の試験結果をまとめて表３に示す。

Using this sealing material, each test was performed using a transfer molding machine under conditions of a mold temperature of 180 ° C., a molding pressure of 70 kgf / cm, and a curing time of 90 seconds.
The spiral flow was measured by EMMI 1-66.
The hot hardness was measured with a Shore hardness meter.
Further, using this sealing material, a semiconductor element was molded under the same conditions with a transfer molding machine, and after post-cure (175 ° C./5 h), moisture resistance and solder heat resistance were evaluated.
The semiconductor device used for moisture resistance is an SOP-28 pin. After pretreatment of 85 ° C./85 RH% 72 hours moisture absorption + 215 ° C./90 seconds (VPS), it is left in PCT (121 ° C./2 atm) and Chip. The presence or absence of a cross section of the upper wiring was evaluated.
The semiconductor device used for solder heat resistance is a QFP 80 pin resin-encapsulated semiconductor device (outer dimensions 20 × 14 × 2.0 mm), and the lead frame is 42 alloy material (no processing) and has a chip size of 8 × 10 mm. It is what has.
With respect to the resin-encapsulated semiconductor device thus obtained, the solder heat resistance was measured by the following method.
After baking at 125 ° C./24 h, after absorbing moisture for a predetermined time at 85 ° C./85% RH, the crack generation rate of the resin-encapsulated semiconductor device when processing at 240 ° C./10 sec was determined.
The test results are summarized in Table 3.

Claims (5)

(A) biphenyl type epoxy resin, (B) phenol curing agent, (C) curing accelerator, (D) inorganic filler, and (E) inorganic material core coated with zinc molybdate , (D) an inorganic filler, an epoxy resin composition for semiconductor encapsulation according to claim Rukoto is 70 to 95 wt% blended.   The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the inorganic substance is talc, magnesium oxide, silicon oxide or the like.   The epoxy resin composition for semiconductor encapsulation according to claim 1 or 2, further comprising (F) an ion trapper.   (F) The epoxy resin composition for semiconductor encapsulation according to claim 3, wherein the ion trapper is hydrotalcite or antimony-bismuth.   A semiconductor device, wherein the semiconductor device is sealed using the epoxy resin composition for semiconductor sealing according to claim 1.