JP3392012B2 - Epoxy resin composition for encapsulating semiconductor element and semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a light emitting element such as an LED, a phototransistor, a photodiode, and a CC.
The present invention relates to an epoxy resin composition used for sealing a light receiving element such as D, a semiconductor element (optical semiconductor element) such as EPROM, and a semiconductor device formed using this epoxy resin.

[0002]

2. Description of the Related Art Epoxy resin compositions, which are excellent in transparency, moisture resistance, adhesion, electrical insulation and heat resistance, are mainly used as a sealing material for semiconductor elements such as light emitting elements and light receiving elements. The mainstream is resin encapsulation using this epoxy resin composition. Above all, the method of resin-sealing by transfer molding using an epoxy resin composition is excellent in workability and mass productivity.

The epoxy resin composition used for this transfer mold contains polyethylene wax, fatty acid having 26 or less carbon atoms, fatty acid ester, fatty acid amide wax, natural carnauba wax, in order to improve releasability from the mold. Waxes such as silicone-based wax and fluorine-based wax are blended as an internal release agent. However, since transparency is important for the sealing material of semiconductor elements such as light emitting elements and light receiving elements, it is necessary to be compatible with other materials such as epoxy resin as the internal mold release agent. Only those with a low releasing effect can be used, and the addition amount is limited to a small amount,
It was an epoxy resin composition having low releasability. Therefore, in order to secure and improve the releasability from the mold, a fluorine-based or silicone-based spray-type external mold release agent is sprayed onto the mold to perform transfer molding.

[0004]

However, when the external mold release agent is used as described above, a step of spraying the mold is required, which deteriorates the molding cycle of the transfer mold and lowers the production efficiency. There was a problem. The present invention has been made in view of the above points, and prevents a decrease in production efficiency by not using an external release agent, and forms a sealing material having high transparency without white turbidity or the like. It is an object of the present invention to provide a semiconductor element-encapsulating epoxy resin composition which can be used, and a semiconductor device using the same.

[0005]

The epoxy resin composition for encapsulating a semiconductor element according to claim 1 of the present invention is for encapsulating a semiconductor element containing an epoxy resin, a curing agent, a curing accelerator and a release agent. An epoxy resin composition, which is obtained by ethoxylating a linear alcohol having 25 or more carbon atoms and having an ethoxylation content of 40 to 90% by weight, is used as the release agent. A silane coupling agent containing a mercapto group is added in an amount of 0.1 to 5% by weight based on the total amount of the resin, the curing agent, the curing accelerator, and the release agent.
It is characterized by containing .

The epoxy resin composition for encapsulating a semiconductor element according to a second aspect of the present invention comprises, in addition to the constitution of the first aspect, a release agent having a molecular weight of 500 to 3,000. It is characterized by .

A semiconductor device according to claim 3 of the present invention
The epoxy resin composition for encapsulation comprises, in addition to the constitution of claim 1 or 2 , the silane coupling agent in the total amount of the epoxy resin, the curing agent, the curing accelerator, the release agent and the silane coupling agent. On the other hand, it is characterized by being mixed in an amount of 5% by weight or less.

A semiconductor device according to a fourth aspect of the present invention is characterized in that the semiconductor element is encapsulated with the epoxy resin composition for encapsulating a semiconductor element according to any one of the first to third aspects. It is a thing.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. The epoxy resin is not particularly limited as long as it has two or more epoxy groups in one molecule, but a resin with relatively little coloration is preferable for use, and a bisphenol A type epoxy resin or a bisphenol F type epoxy resin is used. , Bisphenol S type epoxy resin, orthocresol novolac type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin, triglycidyl isocyanurate, aliphatic epoxy resin, etc., and these are used alone. Or, they can be used together (it is easier to make a solid resin together or alone when making a tablet).

The curing agent is not particularly limited as long as it can undergo a curing reaction with an epoxy resin, but those with relatively little coloration are preferred for use, such as hexahydrophthalic anhydride or methylhexahydrophthalic anhydride. Examples thereof include acid anhydrides such as tetrahydrophthalic anhydride, and novolac type resins obtained by subjecting phenol, cresol, xylenol, resorcin, and the like to a condensation reaction with formaldehyde. In addition to this, an amine-based curing agent can also be used, but since discoloration during curing may increase, it is necessary to take precautions such as adding a relatively small amount. Further, these curing agents can be used alone or in combination, but it is preferable to use a phenol novolac type resin in an amount of 20 to 70% by weight based on the total amount of the curing agents.

The curing accelerator is not particularly limited as long as it has the action of promoting the reaction between the epoxy resin and the curing agent, but those with relatively little coloration are preferred for use, such as triphenylphosphine and diphenylphosphine. Of organic phosphine, 2-methylimidazole, 2-
Imidazole compounds such as phenyl-4-methylimidazole and 2-phenylimidazole, tertiary amine compounds such as 1,8-diaza-bicyclo (5,4,0) undecene-7, triethanolamine and benzyldimethylamine, tetraphenyl Examples thereof include tetraphenylborate compounds such as phosphonium tetraphenylborate, and these can be used alone or in combination.

As the release agent, the one represented by the following general formula (a) is used.

[0013]

[Chemical 1]

The releasing agent is an ethoxylated linear alcohol having a carbon number of 25 or more (primary alcohol), which is a linear ether having ethyl ether in the molecule. is there. In the case of ethoxylation based on a linear alcohol having less than 25 carbon atoms,
Although it is excellent in transparency, it is not preferable because the effect of releasability is low. The upper limit of the number of carbon atoms is naturally defined by the general formula (a), but is about 160. Further, in order to secure stable releasability and transparency, X and Y in the general formula (a) above are used.
It is preferable that X is an integer of 10 to 30 and Y is an integer of 10 to 50.

Further, the molecular weight of the releasing agent is preferably 500 to 3000 in order to obtain stable releasing property and transparency. If the molecular weight is less than 500, the transparency will be high, but the effect of releasability will be low, and continuous molding may not be possible. If the molecular weight exceeds 3,000,
Releasability is high, but transparency is low. Further ethoxylation content of the release agent (weight ratio of ethoxy moieties in the molecule (Y portion)) are Ru 40-90 wt% der in order to obtain stable releasability and transparency. If the ethoxylated content is less than 40% by weight, the transparency may be lowered, and if the ethoxylated content exceeds 90% by weight, the transparency is increased but the releasability effect is lowered and moisture absorption is reduced. Therefore, there is a possibility that it may become cloudy when absorbing moisture or the moisture resistance reliability may be significantly reduced. However, it is possible to use a mixture having an ethoxylation content of 40 to 90% by weight and an ethoxylation content of less than 40% by weight so as not to cause clouding.

The amount of the above-mentioned releasing agent is 0.1 to 5% by weight based on the total amount of the epoxy resin, the curing agent, the curing accelerator and the releasing agent in order to obtain stable releasing property and transparency. Set to%. If the blending amount is less than 0.1% by weight, the transparency will be high, but the effect of releasability will be low, and continuous molding may not be possible. If the blending amount exceeds 5% by weight, moisture absorption will occur. Occasionally, it may become cloudy or the adhesiveness with a semiconductor element may be deteriorated, resulting in a great decrease in the moisture resistance reliability.

The epoxy resin composition for encapsulating a semiconductor device of the present invention has a specific molecular structure as described in (a) above and a specific polar group ((OCH ₂ CH ₂ ) _Y OH).
Since the mold release agent containing is incorporated, the mold releasability from the mold can be improved, and the encapsulant obtained by molding and curing the mold can prevent clouding. Conventionally used wax has a good mold releasability from the mold, but it is difficult to be compatible with other materials such as epoxy resin. Therefore, when it becomes a sealing material (molded product), it becomes cloudy and light Although the transmittance tends to be greatly reduced, since the epoxy resin composition for encapsulating a semiconductor element of the present invention contains a release agent having the structure of the above general formula (a), it is released from the mold. It is possible to form the encapsulating material and the semiconductor device which have excellent properties, have no opaque appearance, and have excellent light transmittance. Moreover, since it is not necessary to use a spray type external release agent, the molding efficiency does not decrease, the cost including the cost of the external release agent can be kept low, and the solvent contained in the external release agent can be reduced. It is possible to prevent problems such as adversely affecting the environment from occurring.

The epoxy resin composition for encapsulating a semiconductor element of the present invention is prepared by using the above epoxy resin, a curing agent, a curing accelerator and a release agent as essential materials. In addition to this, a silane having a mercapto group is also used. It blended system coupling agent. From a structural point of view, this coupling agent acts as a compatibilizer that facilitates compatibility of the release agent with the epoxy resin, the curing agent, and the curing accelerator. By increasing the compatibility of the release agent with the agent, transparency can be improved without lowering the effect of releasability.

The amount of the coupling agent to be added can be set to 5% by weight or less based on the total amount of the epoxy resin, the curing agent, the curing accelerator, the release agent and the coupling agent.
If the blending amount exceeds 5% by weight, it tends to absorb moisture, resulting in cloudiness during moisture absorption or a significant decrease in moisture resistance reliability. Therefore, the compounding amount of the coupling agent is preferably set to 0.1 to 3% by weight.

In addition to the above-mentioned materials, the epoxy resin composition for encapsulating semiconductor elements of the present invention may optionally contain a discoloration inhibitor, an antiaging agent, a dye, an inorganic filler such as silica, a modifier and a plasticizer. It is possible to add agents, diluents and the like.
Then, the epoxy resin composition for semiconductor element encapsulation of the present invention is prepared by melt-mixing the above materials and then melt-mixing them with a high-speed stirring device such as a homomixer or melt-mixing them with a three-roll machine. You can Thereafter, in order to obtain a molding material for transfer molding or the like, it can be cooled and solidified, and then ground, or if necessary, tableted into a tablet. The mixing ratio of the epoxy resin, the curing agent, and the curing accelerator may be the same as that of the conventional epoxy resin composition for semiconductor element encapsulation. Resin 100
The curing agent can be set to 60 to 200 equivalents relative to the equivalent amount, and in the case of the curing accelerator, the compounding ratio can be set to 0.1 to 5% by weight.

When manufacturing a semiconductor device using such an epoxy resin composition for sealing a semiconductor element, the semiconductor element is sealed by transfer molding with a solid (tablet) epoxy resin composition as in the conventional case. After that, the epoxy resin composition may be cured to form a sealing material. When the epoxy resin composition is liquid at room temperature, it can be cast and cured by using a casting method or the like.

[0022]

EXAMPLES The present invention will be described in detail below with reference to examples. (Examples 1 to 6 and Comparative Examples 1 to 6 ) The materials shown in Tables 1 and 2 were compounded in the compounding amounts (units are parts by weight) shown in the same table and put in a stainless steel container equipped with a homomixer stirring device, An epoxy resin composition was prepared by melt mixing at 160 ° C. This was cooled and then pulverized, and the powder was tabletted to form a molding material.

The bisphenol A type epoxy resin in the table is a liquid resin having an epoxy equivalent of 185. Also,
The trifunctional epoxy resin is VG3101H manufactured by Mitsui Petrochemical Co., Ltd., which has an epoxy equivalent of 210. Further, the releasing agent (I) is a linear alcohol ethoxylated product having the structural formula (X = 23, Y = 16) of the above (a), which is a linear alcohol having an average molecular weight of 700 and a hydroxyl equivalent of 65. It is ethoxylated to have a weight ratio of about 50% (melting point 110 ° C./average molecular weight 1400). Further, the releasing agent (II) is a linear alcohol ethoxylated product having the structural formula (X = 20, Y = 44) of the above (a), having an average molecular weight of 700,
About 80% by weight of linear alcohol with a hydroxyl equivalent of 65
Is ethoxylated to have a melting point of 90 ° C /
Average molecular weight 2200). Further, the releasing agent (III) is a linear alcohol ethoxylated product having the structural formula (X = 3, Y = 52) of the above (a), which is a linear alcohol having an average molecular weight of 700 and a hydroxyl equivalent of 65. It is ethoxylated to have a weight ratio of about 95% (melting point 80 ° C./average molecular weight 2400). Further, the release agent (IV) is a linear alcohol ethoxylated product having the structural formula (X = 22, Y = 4) of the above (a), which is a linear alcohol having an average molecular weight of 700 and a hydroxyl equivalent of 65. It is ethoxylated to have a weight ratio of about 20% (melting point 110 ° C./average molecular weight 85
0). The mercaptosilane coupling agent is γ-glycidoxypropyl mercaptosilane. The montanic acid wax is WAX-S manufactured by Hoechst.

This molding material was transfer-molded to prepare a test piece having a thickness of 1 mm. The molding conditions were such that the injection time was 20 seconds, the injection pressure was 80 kgf / cm ² , the cure time was 90 seconds, and the mold temperature was 165 ° C. The test piece thus obtained was measured for light transmittance at 940 nm and 400 nm using a spectrophotometer U-3400 manufactured by Hitachi, Ltd.

Further, in the same manner as above, eight test pieces with a thickness of 1 to 8 mm having different thicknesses of 1 mm were prepared, and each test piece was placed on a line drawn with a pencil of hardness B on white paper. When placed, the line was confirmed from above and the cloudiness was evaluated. Then, even if the test piece with a thickness of 8 mm, the line was confirmed (visible), the circle was ○, and if the line was confirmed (visible) with the test piece with a thickness of 5 to 7 mm, the triangle was 5 mm.
The test pieces below were marked (visible) with lines and were marked with x.

A 16 DIP molded encapsulation product (lead material 42 alloy ~ partial silver plating, 4 x 5 mm aluminum pattern chip ~) using the same epoxy resin composition as described above is used.
A silicon nitride silicate film-5 μm wiring width-25 μm gold wire semiconductor device) was continuously molded by transfer molding, and the maximum number of continuous shots that could be smoothly released was observed up to 100 shots. And OK for those that could perform up to 100 shots without problems, and N for less than 100 shots.
Each G is attached.

Further, 20 pieces of the 16DIP molded encapsulation product formed as described above were taken out, subjected to after-curing treatment at 125 ° C. for 12 hours, and then placed in high temperature and high humidity of 60 ° C. and 95% to cause an open defect. Check the (moisture resistance) every 250 hours and check this up to 100
When the cumulative defective rate exceeds 10% after 0 hours, N
It was set as G, and OK was given to those having a cumulative defective rate of less than 10% after 1000 hours.

The measurement results are shown in Tables 1 and 2.

[0029]

[Table 1]

[0030]

[Table 2]

As can be seen from Tables 1 and 2, Examples 1 to 6
The light transmittance was high and the white turbidity was good, and the continuous releasability and the moisture resistance reliability were high. However, in Comparative Examples 1 to 6 , the light transmittance, the white turbidity, the continuous releasability and the moisture resistance reliability were high. Either one went low. That is, in Examples 1 to 6 , both transparency and moldability could be achieved.

[0032]

As described above, the invention according to claim 1 of the present invention is an epoxy resin composition for semiconductor element encapsulation, which comprises an epoxy resin, a curing agent, a curing accelerator and a release agent. The release agent is obtained by ethoxylating a linear alcohol having 25 or more carbon atoms and has an ethoxylation content of 40 to 9
Since the amount of 0% by weight was used and the release agent was blended in an amount of 0.1 to 5% by weight based on the total amount of the epoxy resin, the curing agent, the curing accelerator and the release agent, the release agent was By compounding, it is possible to prevent the use of an external release agent at the time of molding, prevent a decrease in production efficiency, and form a highly transparent encapsulating material without cloudiness or the like. Is. In particular, stable release properties and transparency can be obtained by adjusting the amount of the release agent to be 0.1 to 5% by weight. Also contains a mercapto group
Since it contains a silane coupling agent that
Those that can be made more transparent without lowering
Is.

Further the invention according to claim 2 of the present invention, since the molecular weight as the release agent used was a 500 to 3,000, Ru der what can be obtain stable releasability and transparency .

The invention according to claim 3 of the present invention is the total amount of the above- mentioned silane coupling agent, which is an epoxy resin, a curing agent, a curing accelerator, a release agent, and a silane coupling agent. Since it is compounded in an amount of 5% by weight or less, stable release properties and high transparency can be obtained.

In the invention according to claim 4 of the present invention, since the semiconductor element is encapsulated with any one of the above epoxy resin compositions for encapsulating a semiconductor element, the transparency of the encapsulant is high and the semiconductor element is high. It is possible to prevent the reception and emission of light from being impaired.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-9-208805 (JP, A) JP-A-9-316177 (JP, A) JP-A-10-158474 (JP, A) JP-A-11- 310710 (JP, A) JP-A 1-2242656 (JP, A) JP-A 8-157695 (JP, A) JP-A 3-195724 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 63/00-63/10 C08K 5/05-5/06 C08K 5/548 H01L 23/29

Claims (4)

(57) [Claims] 1. An epoxy resin composition for encapsulating a semiconductor device, which comprises an epoxy resin, a curing agent, a curing accelerator, and a release agent, wherein a linear alcohol having 25 or more carbon atoms is used as the release agent. Ethoxylated content of 40
˜90% by weight , the release agent is blended in an amount of 0.1 to 5% by weight with respect to the total amount of the epoxy resin, the curing agent, the curing accelerator and the release agent, and contains a mercapto group.
An epoxy resin composition for semiconductor device encapsulation, comprising a silane coupling agent . 2. The release agent has a molecular weight of 500 to 30.
The epoxy resin composition for semiconductor element encapsulation according to claim 1, wherein the epoxy resin composition is 00. 3. The silane coupling agent is epoxy.
Resin, curing agent, curing accelerator, mold release agent, silane coupling agent
5% by weight or less of the total amount of
The epoxy resin composition for semiconductor element encapsulation according to claim 1 or 2 , characterized in that. 4. The semiconductor according to any one of claims 1 to 3.
Encapsulate a semiconductor device with an epoxy resin composition for device encapsulation
A semiconductor device characterized by being formed.