JP4581455B2 - Mold release recovery resin composition and method for manufacturing semiconductor device - Google Patents

Description

  The present invention relates to a mold release recovery resin composition and a method for manufacturing a semiconductor device using the same.

  Epoxy resin composition for semiconductor encapsulation as the integration of semiconductor elements progresses year by year and the surface mounting of semiconductor devices is promoted in the market trend of downsizing, weight reduction and high performance of electronic devices in recent years. The demand for things has become increasingly severe. Epoxy resin compositions for semiconductor encapsulation using various resins and additives that meet this requirement are prone to mold fouling during continuous molding, and mold defects such as unfilling are likely to occur. Therefore, it has become normal to periodically clean the mold surface.

  Conventionally, a semiconductor sealing mold cleaning material consists of a resin having a high molding shrinkage such as an amino resin and a filler having high hardness such as crystal-crushed silica and glass fiber. The main thing was scraping off the dirt on the mold surface. After using the cleaning material, the mold surface will be clean, but the mold release agent will also be removed, so the cured resin of the semiconductor device molded immediately after cleaning is extremely releasable. There was a problem of getting worse. Therefore, after using the cleaning material, it is necessary to mold the mold release recovery resin composition, transfer the mold release agent in the mold release recovery resin composition to the mold surface, and apply it to recover the release properties. is there.

The function of the mold release recovery resin composition is to transfer and apply the release agent to the mold surface, and to quickly recover the release property, but if a large amount of release agent is transferred, After that, there is a problem of causing oil floating or dirt on the surface of the cured resin of the molded semiconductor device. If the release agent cannot be transferred sufficiently, the release property cannot be recovered, and a large amount of the release recovery resin composition is required. The problem arises that it is necessary to use the Furthermore, when the releasability after recovery of releasability cannot be sustained for a long time, it is necessary to frequently use a releasable recovery resin composition, and productivity is lowered.
For this reason, a technique for improving mold release sustainability by adding an antioxidant to a montanic acid ester wax or oxidized or non-oxidized polyethylene wax as a mold release agent is disclosed (for example, see Patent Document 1). ). Although these methods improve the mold release sustainability, the problem of oil floating and dirt cannot be solved sufficiently.

JP-A-4-259513 (pages 2-5)

  The present invention has been made to solve the conventional problems as described above, and the object of the present invention is to recover the releasability even with a small number of shots. A mold release recovery resin composition for semiconductor sealing that does not cause oil floating or dirt on the surface of the cured resin product of the apparatus and can maintain a long release property, and a mold release using the mold release recovery resin composition. The present invention provides a method for manufacturing a resin-encapsulated semiconductor device that restores moldability.

The present invention
[1] (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator, and (D) a resin composition mainly composed of an inorganic filler, further (E) one general formula (1 semiconductor encapsulation mold release recovery resin composition a compound represented by, characterized in that it comprises from 2.0 to 10% by weight of the total resin composition)

(However, n in the formula is an average value and is a positive number of 12 to 50.)

[2] In a method for producing a resin-encapsulated semiconductor device in which a semiconductor element is molded and encapsulated using a resin composition for encapsulating a semiconductor, a mold-release recovery resin composition for encapsulating a semiconductor according to item [1] A method for manufacturing a resin-encapsulated semiconductor device, wherein the mold release property of the molding die is restored using
It is.

  According to the present invention, the releasability can be recovered even with a small number of shots, and no oil floating or dirt is generated on the surface of the cured resin of the semiconductor device immediately after the releasability is recovered, and the releasability is maintained for a long time. Since it contributes to the productivity improvement of the resin-encapsulated semiconductor device, it is industrially useful.

The present invention relates to a molding die using a mold release recovery resin composition comprising an epoxy resin, a phenol resin, a curing accelerator, and an inorganic filler as main components and an ester compound having a special structure as an essential component. By releasing the mold releasability, it is possible to recover the mold releasability even with a small number of shots. A remarkable effect that the moldability can be maintained for a long time is obtained.
Hereinafter, the present invention will be described in detail.

  Although it does not specifically limit as an epoxy resin used by this invention, For example, a phenol novolak type epoxy resin, a cresol novolak type epoxy resin, a biphenyl type epoxy resin, a bisphenol type epoxy resin, a stilbene type epoxy resin, a triphenolmethane Type epoxy resin, phenol aralkyl type epoxy resin, naphthalene type epoxy resin, alkyl-modified triphenol methane type epoxy resin, triazine nucleus-containing epoxy resin, dicyclopentadiene-modified phenol type epoxy resin, etc. It may be used.

The phenolic resin used in the present invention is not particularly limited. Examples thereof include phenol aralkyl resins having a phenylene and / or diphenylene skeleton, and these may be used alone or in combination.
The blending ratio of the epoxy resin and the phenol resin is not particularly limited, but the ratio of epoxy group / phenolic hydroxyl group is preferably 0.7 to 1.5, more preferably 0.9 to 1.2. desirable. If it deviates significantly from this range, the mold release recovery resin composition may not be sufficiently cured, and workability such as deterioration of mold release may be deteriorated.

  The curing accelerator used in the present invention is one that can be a catalyst for the crosslinking reaction between the epoxy resin and the phenol resin, and examples thereof include tributylamine, 1,8-diazabicyclo (5,4,0) undecene-7, and the like. Amine compounds, organic phosphorus compounds such as triphenylphosphine and tetraphenylphosphonium tetraphenylborate salts, and imidazole compounds such as 2-methylimidazole, but are not limited thereto. These curing accelerators may be used alone or in combination.

  As an inorganic filler used for this invention, what is generally used for the epoxy resin composition for semiconductor sealing can be used. Examples thereof include fused spherical silica, fused crushed silica, crystalline silica, talc, alumina, titanium white, silicon nitride and the like, and the most suitably used is spherical fused silica. These inorganic fillers may be used alone or in combination. These may be surface-treated with a coupling agent.

Since the compound represented by the general formula (1) used in the present invention has a function of improving the releasability, the mold releasable recovery resin composition using the compound is used after the cleaning material is used. The mold releasability can be recovered immediately. N in the compound represented by the general formula (1) is an average value and is a positive number of 12 to 50. If the value of n is less than the lower limit value, the molecular weight is low and the thermal stability is not excellent. Further, if the value of n exceeds the upper limit value, it exudes excessively to the mold surface, which is excellent in terms of the mold release recovery effect. This is not preferable because it has a drawback of causing floating and dirt.

  The compounding quantity of the compound represented by General formula (1) is 0.1 to 10 weight% in all the epoxy resin compositions. If the value is below the lower limit, the compound represented by the general formula (1) does not sufficiently migrate to the mold surface, and there is a possibility that the expected mold release recoverability cannot be obtained. When the upper limit is exceeded, there is a problem that the surface of the mold is excessively oozed and oil floating occurs in the semiconductor device immediately after the release of the mold release.

In addition to the components (A) to (E), the mold release recovery resin composition for semiconductor encapsulation of the present invention includes a mold release agent such as carnauba wax, stearic acid, and montanic acid wax as needed. Additives such as colorants such as ring agents, antioxidants, and carbon black may be used.
The mold release recovery resin composition for semiconductor encapsulation of the present invention is obtained by mixing the raw materials sufficiently uniformly using a mixer or the like, then melt-kneading with a hot roll or kneader, etc., cooling and pulverizing. .

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The blending ratio is parts by weight.
The ester compounds used in Examples and Comparative Examples are summarized below.
Compound 1: Compound represented by formula (1) (n = 12)
Compound 2: Compound represented by formula (1) (n = 46)
Compound 3: Compound represented by formula (1) (n = 52)
Compound 4: Compound represented by formula (1) (n = 8)

Example 1
Mold release recovery resin composition 1
Orthocresol novolac type epoxy resin (softening point 65 ° C., epoxy equivalent 209)
20.20 parts by weight Phenol novolac resin (softening point 90 ° C., hydroxyl group equivalent 104) 10.00 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU)
0.20 parts by weight Fused spherical silica (average particle size 28 μm) 67.00 parts by weight Compound 1 2.00 parts by weight Carnauba wax 0.30 parts by weight Carbon black 0.30 parts by weight were mixed using a mixer. Thereafter, the mixture was kneaded 20 times using biaxial rolls having surface temperatures of 95 ° C. and 25 ° C., and the obtained kneaded material sheet was cooled and pulverized to tablet a pulverized material of 4 mesh or less. The properties of the obtained mold release recovery resin composition were evaluated by the following methods. The evaluation results are shown in Table 1.

Evaluation molds and evaluation materials The evaluation molds and evaluation materials used for evaluation of mold release recoverability, mold release sustainability, and molded product stains are shown below.
Evaluation mold: Upper mold, middle mold shown in FIG. 1, and lower mold, the shape of the molded product adhering to the middle mold after molding is 14.0 mm in diameter and 1.5 mm in height (for transfer molding) .
Evaluation material: Sumitomo Bakelite Co., Ltd., epoxy resin molding material for semiconductor encapsulation EME-7351

Evaluation Method Mold Release Recovery: Using a melamine resin cleaning material (EMEC3, manufactured by Sumitomo Bakelite Co., Ltd.) for cleaning the mold surface, a molded product is molded with an evaluation mold, and the surface of the mold After the mold release agent component was removed, the mold release recovery resin composition was molded three times, and then the evaluation material (Sumitomo Bakelite, under conditions of a mold temperature of 175 ° C., an injection pressure of 6.9 MPa, and a curing time of 2 minutes) (Transfer molding epoxy resin molding material EME-7351, manufactured by Co., Ltd.), push the push-pull gauge from the hole at the top of the evaluation mold and project the molded product, and measure the release load applied at that time did. The unit is MPa. The criterion was 30 MPa or higher as unacceptable and less than 30 MPa as acceptable.

  Mold release sustainability: After molding a molded product with an evaluation mold using a melamine resin-based cleaning material for cleaning the mold surface, and removing the mold release agent component on the mold surface, the mold After the mold release recovery resin composition is molded three times, the molding material is transfer molded at a mold temperature of 175 ° C., an injection pressure of 6.9 MPa, and a curing time of 2 minutes, and a push-pull gauge is inserted from the upper hole of the mold. The molded product was ejected by hitting, and the release load applied at that time was measured. Subsequently, 200 shots of the evaluation material were molded, and the change in the release load for each shot was measured. At this time, the number of shots when the load was 80 MPa or more was described in the results. 200 <means 200 shots or more, and expresses that the load is 80 MPa or less even after 200 shots. The judgment criteria were less than 150 shots as unacceptable and 150 shots or more as acceptable.

  Molded product dirt: A molded product is molded with an evaluation mold using a melamine resin cleaning material for cleaning the mold surface, the mold release agent component on the mold surface is removed, and then the mold release is performed. After the mold recovery resin composition was molded three times, the evaluation material was transfer molded at a mold temperature of 175 ° C., an injection pressure of 6.9 MPa, and a curing time of 2 minutes. Oil floating and dirt on the molded product surface of the molded evaluation material were confirmed. The case where oil floating or dirt occurred on the surface of the cured product was indicated as x, and the case where there was no oil floating or dirt was indicated as ○.

Examples 2 , 4, 5, Reference Example 3 , Comparative Examples 1-5
According to the formulation of Table 2, a mold release recovery resin composition was prepared in the same manner as in Example 1, and evaluated in the same manner as in Example 1. The results are shown in Table 1. The biphenyl type epoxy resin (YX-4000 manufactured by Japan Epoxy Resin Co., Ltd.) used in Example 2 has a melting point of 105 ° C. and an epoxy equivalent of 195. The phenol aralkyl resin (Mitsui Chemicals, XL-225) used in Example 2 has a softening point of 79 ° C. and a hydroxyl group equivalent of 174.

  According to the present invention, the releasability can be recovered even with a small number of shots, and no oil floating or dirt is generated on the surface of the cured resin of the semiconductor device immediately after the releasability is recovered, and the releasability is maintained for a long time. Since it contributes to the productivity improvement of the resin-encapsulated semiconductor device, it is industrially useful.

It is the top view seen from the lower surface side of the state with which the middle mold of the evaluation metal mold was filled with cal, runner and molded product. It is an expanded sectional view of the A section of FIG.

Explanation of symbols

1 Medium size 2 Cal 3 Runner 4 Molded product 5 Air vent 6 Handle 7 Hole for push-pull gauge insertion

Claims (2)

(A) An epoxy resin, (B) a phenol resin, (C) a curing accelerator, and (D) a resin composition containing as a main component an inorganic filler, further represented by (E) the general formula (1) The mold release recovery resin composition for semiconductor encapsulation, comprising 2.0 to 10% by weight of the compound to be contained in the total resin composition.
(However, n in the formula is an average value and is a positive number of 12 to 50.) In the manufacturing method of the resin sealing type semiconductor device which shape-seals a semiconductor element using the resin composition for semiconductor sealing, a mold metal using the mold release recovery resin composition for semiconductor sealing according to claim 1 A method for manufacturing a resin-encapsulated semiconductor device, wherein mold release properties are restored.