JP2009007415A - Epoxy resin composition for sealing semiconductor and semiconductor device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition for sealing a semiconductor having excellent reflow crack resistance. <P>SOLUTION: The epoxy resin composition for sealing the semiconductor comprises an epoxy resin, a curing agent, an inorganic filler and further a thiocresol. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an epoxy resin composition for semiconductor encapsulation and a semiconductor device encapsulated using the same.

  In sealing of electrical and electronic parts and semiconductor devices, epoxy resin is superior in moldability, adhesiveness, electrical properties, mechanical properties, moisture resistance, etc. compared to other thermosetting resins. It is common to use an epoxy resin composition as a material. And until now, what has various compounding compositions according to the target characteristic, a use, etc. is proposed. For example, an epoxy resin composition containing a thiophenol derivative or a sulfur-containing compound is known in order to improve adhesion to a metal lead frame, silicon chip, silver or gold plating surface (for example, Patent Document 1). , 2).

  By the way, in recent years, with the reduction in size and thickness of electronic devices, surface mount packages are increasing. Since this surface mount package is directly exposed to the solder temperature, if the package absorbs moisture, moisture will rapidly expand during soldering, causing peeling inside the package and causing package cracks. It becomes. For this reason, a sealing material having good crack resistance during soldering, so-called reflow crack resistance, is required.

In order to solve this problem, for example, it is conceivable to suppress moisture absorption of the package using a sealing material in which an inorganic filler is highly filled. However, due to the high filling of the inorganic filler, the fluidity at the time of molding of the sealing material is reduced, leading to poor molding, deterioration of quality reliability and stability, so there is a limit to the amount of inorganic filler used. . Therefore, as a result, a significant improvement in reflow crack resistance cannot be expected.
JP 2007-63549 A JP 2001-55483 A

  This invention is made | formed in view of the above situations, and makes it a subject to provide the epoxy resin composition for semiconductor sealing excellent in reflow crack resistance.

  The present invention is characterized by the following in order to solve the above problems.

  1stly, the epoxy resin composition for semiconductor sealing of this invention contains a thiocresol with an epoxy resin, a hardening | curing agent, and an inorganic filler.

  Second, in the first epoxy resin composition for encapsulating a semiconductor, the content of thiocresol is in the range of 0.01 to 0.5% by mass with respect to the total amount of the epoxy resin composition for encapsulating a semiconductor. .

  Thirdly, the semiconductor device of the present invention is sealed with a cured product of the above-described epoxy resin composition for semiconductor sealing.

  According to the first invention, by containing thiocresol, good reflow crack resistance can be realized even when a large amount of inorganic filler is blended.

  According to the second aspect of the present invention, the effect of the first aspect of the present invention is more certain and remarkable by setting the blending ratio of thiocresol within a specific range.

  According to the third aspect of the present invention, a semiconductor device having excellent reflow crack resistance as described above is realized.

  In the epoxy resin composition for semiconductor encapsulation of the present invention, as described above, together with the epoxy resin, the curing agent, and the inorganic filler, the following formula

The thiocresol represented by these is contained as an essential component. Although there are o-, m-, and p-thiocresol, p-thiocresol is preferable in consideration of moisture resistance.

  As content of thiocresol, 0.01-0.5 mass% is considered as a preferable range with respect to the epoxy resin composition whole quantity for semiconductor sealing. Thereby, the moisture resistance and adhesiveness after moisture absorption reflow can be improved, and reflow crack resistance can be improved. If it is less than 0.01% by mass, the moisture resistance and adhesion after moisture absorption reflow are not sufficient, and if it exceeds 0.5% by mass, the moisture resistance, adhesion and fluidity after moisture absorption reflow are reduced. This is not preferable because it tends to cause

  In the epoxy resin composition for semiconductor encapsulation of the present invention, the epoxy resin may be various epoxy resins generally used for semiconductor encapsulation, and is not particularly limited. For example, phenol novolac type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin, triphenolmethane type epoxy resin, phenol aralkyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy Examples thereof include resins. These are not limited to one type, and a plurality of types may be used in combination. This epoxy resin can be mix | blended in 5 to 35 mass% with respect to the epoxy resin composition whole quantity for semiconductor sealing.

  Moreover, as a hardening | curing agent, the various things generally used for semiconductor sealing can be applied. Specific examples include phenol novolac resins, dicyclopentadiene type phenol resins, phenol aralkyl resins, cresol novolac resins, naphthol aralkyl resins, and the like, naphthalene skeleton-containing phenol resins, and polyhydric phenol compounds. These are not limited to one type, and a plurality of types may be used in combination. Although content of a hardening | curing agent is not specifically limited, For example, it can mix | blend so that the equivalent ratio of an epoxy resin and a hardening | curing agent may be 0.5-1.5, Preferably it is 0.8-1.2.

  Furthermore, the inorganic filler is not particularly limited as long as it is generally used for semiconductor sealing. Examples thereof include fused silica, crystalline silica, alumina, silicon nitride, and aluminum nitride. Although content of an inorganic filler is not specifically limited, For example, it can be 60-93 weight% with respect to the epoxy resin composition whole quantity for semiconductor sealing.

  The present invention may be used in combination with a curing accelerator, and is not particularly limited as long as it has an action of promoting the reaction between the epoxy resin and the curing agent. Examples thereof include organic phosphines such as tetraphenylphosphonium / tetraphenylborate and triphenylphosphine, tertiary amines such as diazabicycloundecene, and imidazoles such as 2-methylimidazole and 2-phenylimidazole. These may be used alone or in combination.

  In the present invention, a coupling agent can be blended. As the coupling agent, a mercaptosilane such as γ-mercaptopropyltrimethoxysilane, a glycidoxysilane such as γ-glycidoxypropyltrimethoxysilane, or a silane coupling agent such as aminosilane can be used. These may be used alone or in combination.

  The present invention further includes a colorant such as carbon black, a carnauba wax, a fatty acid amide, a stearic acid, a montanic acid amide, a fatty acid ester, a release agent such as a carboxyl group-containing polyolefin, a silicone flexible agent, and a bromination as necessary. Flame retardants such as epoxy resins, flame retardant aids such as antimony trioxide, and the like can be added.

  The epoxy resin composition for semiconductor encapsulation of the present invention contains an epoxy resin, a curing agent, an inorganic filler, thiocresol, and various additives as necessary, and after uniformly mixing with a mixer or blender. It can be prepared by kneading with a heating roll or a kneader. Here, the blending order of each of the above components is not particularly limited, and the kneaded product may be cooled and solidified as necessary, pulverized into pellets or powder, or used as a tablet. it can.

  And a semiconductor device can be produced by carrying out sealing molding using the epoxy resin composition for semiconductor sealing prepared in this way. For example, a semiconductor device in which a semiconductor element is encapsulated with an epoxy resin composition for encapsulating a semiconductor can be manufactured by setting a lead frame on which a semiconductor element such as an IC is mounted in a transfer mold and performing transfer molding. It can be done. In the semiconductor device thus obtained, the adhesion of the epoxy resin composition for semiconductor encapsulation to the semiconductor element and the lead frame is high, and moisture absorption is also suppressed, so that the reflow crack resistance is excellent.

  Hereinafter, examples will be shown, and the embodiments of the present invention will be described in more detail. Of course, the present invention is not limited to the following examples, and it goes without saying that various aspects are possible in detail.

<Examples 1-6, Comparative Examples 1-4>
Each material is blended in the blending amounts shown in Table 1, mixed for 30 minutes with a blender, homogenized, kneaded and melted with two rolls heated to 80 ° C., extruded, cooled, and then adjusted to a predetermined particle size with a pulverizer. The pulverized epoxy resin composition for semiconductor encapsulation was obtained by pulverization.

  In addition, as an epoxy resin, epoxy resin 1: o-cresol novolak type epoxy resin (Sumitomo Chemical Co., Ltd. ESCN195XL epoxy equivalent 195), epoxy resin 2: biphenyl type epoxy resin (Japan epoxy resin YX4000H epoxy equivalent 196) used.

  Further, as the curing agent, curing agent 1: phenol novolak resin (Tamanol 752 hydroxyl equivalent 104 manufactured by Arakawa Chemical Co., Ltd.), curing agent 2: phenol aralkyl resin (XL-225 hydroxyl equivalent 176 manufactured by Mitsui Chemicals, Inc.). used.

  Further, fused silica (FB820 manufactured by Electrochemical Co., Ltd.) was used as an inorganic filler, and p-thiocresol (manufactured by Wako Pure Chemical Industries, Ltd.) was used as thiocresol.

  In addition, γ-glycidoxypropyltrimethoxysilane (KBM403 manufactured by Shin-Etsu Chemical Co., Ltd.) as a coupling agent, carbon black (40B manufactured by Mitsubishi Chemical) as a colorant, and triphenylphosphine (Hokuko Chemical) as a curing accelerator. Carnauba wax (Daiichi Chemical F1-100) was used as a mold release agent.

The above-mentioned epoxy resin composition for sealing was transfer molded (mold temperature: 175 ° C., injection pressure: 70 kgf / cm ² , molding time: 90 seconds, post-curing: 175 ° C./6 h), and the following measurement method was used. Characteristics were evaluated.
<Spiral flow>
Using a spiral flow measuring mold in accordance with ASTM D3123, molding was performed under the above transfer molding conditions, and the flow distance (cm) was measured.
<Reflow crack resistance 1>
A 128 pin QFP package having an outer dimension of 14 × 14 × 2.7 mm, in which a test chip having a size of 8 × 9 × 0.4 mm is mounted on a Cu lead frame using a silver paste, is molded under the transfer molding conditions described above. After absorbing moisture for 168 hours under the condition of 85% RH, reflow treatment was performed under the conditions of 240 ° C. and 10 seconds using an IR reflow apparatus to confirm the presence or absence of cracks. The resistance to reflow cracking was evaluated by the number of crack generation packages relative to the number of test packages.
<Reflow crack resistance 2>
The evaluation was performed in the same manner as in the reflow crack resistance 1 except that the moisture absorption time was 72 h, 96 h, and 168 h, and the reflow treatment was performed at 260 ° C. for 10 seconds using an IR reflow apparatus.

  The results are shown in Table 1.

  As seen in Table 1, the epoxy resin composition for semiconductor encapsulation containing the epoxy resin, the curing agent, the inorganic filler, and thiocresol (Examples 1 to 6) has no problem in the flow distance by spiral flow. It was confirmed that the reflow crack resistance was good. In particular, the epoxy resin composition for semiconductor encapsulation (Examples 5 and 6) in which the content of thiocresol is in the range of 0.01 to 0.5 mass% with respect to the total amount of the epoxy resin composition for semiconductor encapsulation, The occurrence of cracks after moisture absorption reflow was not observed, and it was confirmed that the film was excellent in reflow crack resistance.

  On the other hand, in the epoxy resin composition for semiconductor encapsulation that does not contain thiocresol (Comparative Examples 1 to 4), occurrence of cracks was observed after moisture absorption reflow.

  From the above, it was confirmed that the present invention provides an epoxy resin composition for semiconductor encapsulation excellent in reflow crack resistance.

Claims (3)

  The epoxy resin composition for semiconductor sealing characterized by containing thiocresol with an epoxy resin, a hardening | curing agent, and an inorganic filler.   The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the content of thiocresol is in the range of 0.01 to 0.5 mass% with respect to the total amount of the epoxy resin composition for semiconductor encapsulation. object.   A semiconductor device sealed with a cured product of the epoxy resin composition for sealing according to claim 1.