JPH11209579A - Sealing epoxy resin composition and resin-sealing type photosemiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject resin composition improving adhesiveness with a lead frame and processability in subsequent processes without damaging releasability to a mold or an appearance of a molded product, having excellent reliability in moisture resistance and useful for a photosemiconductor element, etc., by including a mercapto group-containing silane compound. SOLUTION: This sealing epoxy resin composition contains an epoxy resin such as a bisphenol A type epoxy resin, a hardener such as a hexahydrophthalic anhydride, a hardening accelerator such as triphenylphosphine and preferably 0.001-5 wt.% (based on the weight of the whole composition) of a mercapto group-containing silane compound such as a compound obtained by previously hydrolyzing and reacting with an epoxy resin. Preferably, the composition further contains an ethoxy compound of an >=18C linear primary alcohol and preferably a resin-sealing type semiconductor device is produced by using the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED, a phototransistor, a photodiode, a CCD, and an EPROM.
The present invention relates to an epoxy resin composition used for sealing an optical semiconductor element such as an optical semiconductor device, and an optical semiconductor device sealed with the epoxy resin composition.

[0002]

2. Description of the Related Art As an encapsulating material for optical semiconductors such as light-emitting elements and light-receiving elements, resin encapsulation with an epoxy resin composition is preferred because of its excellent transparency, adhesion, moisture resistance, electrical insulation, heat resistance and the like. It has become mainstream. As these sealing methods, an optical semiconductor device is generally manufactured by a method of transfer molding a tablet when solid at room temperature, or by casting, potting, printing or the like when liquid at room temperature. Among them, resin encapsulation by transfer molding using an epoxy resin composition is excellent in workability and mass productivity.

[0003] Here, in the encapsulant for optical semiconductors, since transparency is regarded as the most important factor, it is difficult to add a large amount of an inorganic filler such as silica to the epoxy resin composition. For this reason, in the molded body, the thermal expansion coefficient of the epoxy resin composition is about 70 ppm, and the thermal expansion coefficient of the element and the lead frame is about 5 to 17 ppm. .

The epoxy resin composition used for the transfer mold is generally added with an internal release agent in order to improve the releasability from the mold. For this reason, according to the conventional technology, even if the epoxy resin composition and the inner (element and lead frame) are in close contact with each other immediately after the mold and after-cure, due to external stress applied during subsequent processing such as deburring and solder plating. There is a problem that peeling easily occurs. Thus, when peeling occurs during post-processing, moisture or the like that has entered from the peeling interface causes corrosion of the aluminum pad, aluminum wiring, and the like, causing conduction failure and leak failure.

[0005]

In view of the above circumstances,
An object of the present invention is to improve the adhesion to a lead frame and improve post-processing resistance without impairing the releasability from a mold and the appearance of a molded product, and to stably improve the resistance to post-processing. It is an object of the present invention to provide a resin-encapsulated semiconductor device that ensures high moisture resistance reliability.

[0006]

Means for Solving the Problems The present inventors have conducted various studies in order to solve various defects caused by moisture and the like entering from a peeling interface of a molded article and to improve the stability of humidity resistance. Here, since the stress generated due to the difference in thermal expansion coefficient between the epoxy resin composition and the element and the lead frame is very large, very large stress is accumulated at the interface between the sealing resin and the lead frame. For this reason, even if it adheres after the mold and after-curing, it prevents external stress applied to the molded product in the deburring step and peeling caused by interfacial erosion due to chemicals such as alkanol sulfonic acid that come into contact in the solder plating step. I found that it was effective. Therefore, the present inventors have further studied to improve the adhesion between the epoxy resin composition and the lead frame.

As a result, the composition contains an epoxy resin (component A), a curing agent (component B), and a curing accelerator (component C).

[0008]

Embedded image

In the epoxy resin composition to which the mercapto group-containing silane compound (D component) represented by
It has been found that the sulfur atoms in the components form an electrical complex with the metal that is the material of the lead frame, and the adhesion between the epoxy resin composition and the lead frame is more strongly formed. Furthermore, it has been found that a more uniform and strong adhesion can be obtained by pre-reacting the component D with the component A or hydrolyzing the component D in advance. Further, in a silver-plated lead frame in which the surface of a lead frame generally used for an optical semiconductor is silver-plated, a remarkable improvement in the adhesion is achieved. For this reason, external stress is applied in the deburring process,
The present invention has been found that peeling does not occur even when chemicals come into contact in the solder plating step, and various defects due to moisture or the like penetrating from the peeling interface and improvement in stability of humidity resistance can be achieved.

The present invention is characterized in that the epoxy resin composition containing an epoxy resin, a curing agent and a curing accelerator also contains a mercapto group-containing silane compound as a component to achieve the above object. The present invention is also characterized in that in a semiconductor device in which a semiconductor element is sealed with an epoxy resin composition, the epoxy resin composition of the present invention is used as the epoxy resin.

[0011]

Next, the present invention will be described in detail. The epoxy resin composition used in the present invention is composed of essential components of A: epoxy resin B: curing agent C: curing accelerator D: mercapto group-containing silane compound represented by the above general formula.

The epoxy resin as component A is 1
There is no particular limitation as long as the molecule has two or more epoxy groups, but an epoxy resin composition for an optical semiconductor that is relatively less colored is preferable. For example, bisphenol A
Type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, orthocresol novolak type epoxy resin, alicyclic epoxy resin, triglycidyl isocyanurate, aliphatic epoxy resin and the like. These may be used alone or in combination.

The curing agent as the component B is not particularly limited as long as it reacts with the epoxy resin, but it is preferable that the epoxy resin composition for optical semiconductors has relatively little coloring. For example, there is a novolak-type phenol resin obtained by a condensation reaction of an acid anhydride such as hexahydrophthalic anhydride, phenol, cresol, xylenol, resorcin and the like with formaldehyde. In addition, amine-based curing agents can also be used, but when used, care must be taken with regard to the amount added, etc. due to the large discoloration during curing. These may be used alone or in combination.

The content of the component B is preferably such that the equivalent of the curing agent is set in the range of 0.5 to 1.5 with respect to 1 equivalent of the epoxy resin, and particularly preferably 0.7 to 1.0. is there. If the equivalent of the curing agent is less than 0.5, the releasability is poor, and if it exceeds 1.5, the moisture absorption increases, and the reliability tends to deteriorate. The curing accelerator, which is the component C, is not particularly limited as long as it has an action of accelerating the reaction between the epoxy resin and the curing agent, but a relatively less coloring agent is preferred. For example, organic phosphine-based curing accelerators such as triphenylphosphine and diphenylphosphine,
Imidazole-based curing accelerators such as 2-methylimidazole, 2-phenyl-4-methylimidazole and 2-phenylimidazole; 1,8-diazabicyclo (5,4,0)
Examples include tertiary amine curing accelerators such as undecene-7, triethanolamine and benzyldimethylamine, and organic salts such as tetraphenylphosphonium / tetraphenylborate. These may be used alone or in combination.

The content of the component C is preferably set in the range of 0.25 to 5% by weight of a curing accelerator based on the entire epoxy resin composition. The amount of the curing accelerator is 0.25
If the content is less than 5% by weight, the gelation time tends to be slow, and the curing workability tends to be remarkably reduced. There is fear.

The D component refers to a mercapto group-containing silane compound represented by the above general formula. When this D component is added to the epoxy resin composition, there is no problem if it is added as it is, but particularly, by adding a component which has been pre-reacted with the A component in advance, the adhesion strength to the lead frame is uniformly and greatly improved. I do. Furthermore, by pre-reacting the E component obtained by hydrolyzing the D component with the A component, the adhesion strength to the lead frame can be further greatly improved.

It is preferable that the content of the component D is blended so as to be 5% by weight or less based on the whole epoxy resin composition. More preferably 0.001 to 5 wt
% Range. That is, the amount of the component D is 0.001.
If the content is less than 5% by weight, it is difficult to obtain sufficient adhesion to the lead frame. May be caused.

The epoxy resin composition contains 18 carbon atoms.
By containing the ethoxylated product of the linear primary alcohol (component F), an epoxy resin composition having both high adhesion to the lead frame and stable continuous release from the mold at the same time is obtained. be able to. In addition, the epoxy resin composition used in the present invention, in addition to the above, if necessary, a discoloration inhibitor, a deterioration inhibitor, a dye, an inorganic filler such as silica, a silane coupling agent, a modifier, a plasticizer,
A diluent or the like may be blended.

The release agent component referred to herein is not particularly limited, but includes, for example, saturated fatty acid monoamides such as lauric acid amide, unsaturated fatty acid monoamides such as oleic acid amide, N-stearyl stearic acid amide and the like. Substituted amides, methylol amides such as methylol stearic acid amide, saturated fatty acid bisamides such as methylene bis stearic acid amide, unsaturated fatty acid bisamides such as ethylene bisoleic acid amide, and fragrances such as m-xylene bis stearic acid amide Fatty acid amides such as group-based bisamides are preferred for use in optical semiconductors also from the viewpoint of compatibility with the epoxy resin composition.
The mixing ratio of the release agent is 0.25 to 7.5 wt% of the whole composition.
It is preferred that

The epoxy resin composition is melt-mixed or melt-kneaded with an epoxy resin, a curing agent, a curing accelerator, a D component, and other additive components, and then melt-kneaded with three rolls and the like, and cooled and solidified. After that, it can be manufactured by crushing and, if necessary, tableting into tablets. Further, when the properties are liquid at room temperature, it can be produced by dissolution mixing or melt kneading. Then, the epoxy resin composition thus obtained is used for sealing the optical semiconductor element by transfer-molding a tablet when solid, and for casting or potting when printing in a liquid state. An optical semiconductor device can be manufactured by casting and curing in a system.

Using the epoxy resin composition obtained by the above method, the performance was evaluated as follows. (Light Transmittance) Using a spectrophotometer (manufactured by Hitachi, Ltd.), evaluation was made based on the light transmittance in the visible light region of a test piece having a thickness of 1 mm. (Moisture resistance reliability) Silver-plated 4 with TEG on which a comb-shaped aluminum pattern having a width of 10 μm and a thickness of 1 μm is mounted
Two alloy lead frames were subjected to transfer molding using a 16 DIP mold. The molded product was after-cured at 120 ° C. for 16 hours to obtain a 16DIP10 package for performance evaluation. The above 10 packages are 121 ° C and 100% R
A PCT test was performed for 50 hours under the condition of H, and the evaluation was made based on the open defect rate. (Adhesion) The adhesion to the silver-plated lead frame after the deburring step and after the solder plating step was evaluated using an ultrasonic probe (manufactured by Canon). (Adhesion strength) Using a 42 alloy lead frame subjected to silver plating and a Cu frame subjected to silver plating, using a Instron type tensile tester (manufactured by Shimadzu Corp.)
The pull-out strength of the lead portion was evaluated at 2 mm / sec.

The evaluation results are shown in Tables 1 and 2.

[0023]

The present invention will be described below with reference to examples and comparative examples. (Examples 1 to 7 and Comparative Examples 1 to 6) The following substances were used in the amounts shown in Tables 1 and 2, respectively, for the components of Examples and Comparative Examples. Epoxy resins include bisphenol A type epoxy resin (A) (Yuka Kasper Epoxy Co., Ltd.)
Epicoat 828, epoxy equivalent 195), bisphenol A type epoxy resin (a) (Yuika Shell Epoxy Co., Ltd. Epicoat 1001, epoxy equivalent 490),
And o-cresol novolak type epoxy resin (c)
(Sumitomo Chemical ESCN-195XL, epoxy equivalent 19
5) was used alone or in combination. Examples of the curing agent include tetrahydrophthalic anhydride (d) (Rikashid TH, molecular weight 152, manufactured by Nippon Rika Co., Ltd.), and phenol resin (e)
(PSE6200 manufactured by Gunei Chemical, phenol equivalent weight 105)
Was used alone or in combination. 1,8-diazabicyclo (5,4,0) undecene-7 (f) was used as a curing accelerator. As an additive component, montanic acid wax (G)
(WAX-S manufactured by Hoechst), having 1 carbon atom in the F component
An ethoxylated product of 8 or more linear primary alcohols which is 50% by weight ethoxylated to a linear alcohol having an average molecular weight of 700 and a hydroxyl equivalent of 65 (h) (melting point: 11)
0 ° C., average molecular weight 1500). Further, γ-mercaptopropyltrimethoxysilane (TSL8380 manufactured by Toshiba Silicone Co., Ltd.) is used as the component D having the above structure.
(G) was used. As a pre-reaction of the component D with the component A, (A) and (K) may be used in a weight ratio of 1: 1 to 1: 1.
1: 100 and mixed under reflux in a nitrogen atmosphere.
What heated to 0-60 degreeC and made it react for 1 to 5 hours was used. The component E obtained by previously hydrolyzing the component D includes (g), distilled water and alcohol in a weight ratio of 100:
A mixture obtained by heating a mixture of 1 to 100: 1 to 100 at a temperature of 30 to 60 ° C. under reflux in a nitrogen atmosphere and hydrolyzing for 1 to 10 hours was used. Component E was pre-reacted with Component A in advance by mixing (A) and (CO) in a weight ratio of 1: 1 to 1: 100, and refluxing at 30 to 60 ° C. under a nitrogen atmosphere. And reacted for 1 to 5 hours.

[0024]

[Table 1]

[0025]

[Table 2]

According to the results of Tables 1 and 2, as shown in the examples, according to the present invention, compared to the composition not using the mercapto group-containing silane compound represented by the above general formula (Comparative Example 1), Has excellent adhesion and post-process resistance. Further, rather than adding the mercapto group-containing silane compound to the composition as it is as in Comparative Example 2, the use of a pre-reacted epoxy resin or a hydrolyzed mercapto group-containing silane compound is further used. Improved adhesion and post-process resistance can be obtained. Furthermore, by blending an ethoxylated product of a linear primary alcohol having 18 or more carbon atoms, it is possible to achieve both the adhesion to the inner layer and the stable continuous releasability, thereby improving the production efficiency. In addition, transparency has the same performance as the current one, and higher stability can be secured with respect to moisture resistance.

[0027]

As described above, it is possible to obtain an epoxy resin composition excellent in adhesiveness and light transmittance especially when a lead frame plated with silver is used. This makes it possible to provide an epoxy resin composition having excellent adhesion during post-processing such as a deburring step and a solder plating step. In addition, an optical semiconductor device having good moisture resistance reliability can be obtained by using this.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 23/29 H01L 33/00 N 23/31 23/30 F 31/02 31/02 B 33/00

Claims (7)

[Claims] An epoxy resin composition for sealing comprising an epoxy resin, a curing agent and a curing accelerator, wherein the epoxy resin composition further comprises a silane compound having a mercapto group. 2. The epoxy resin composition for sealing according to claim 1, wherein the compounding amount of the silane compound having a mercapto group is 0.001 to 5% by weight based on the whole composition. 3. A mercapto group-containing silane compound which has been previously reacted with an epoxy resin.
The epoxy resin composition for sealing according to the above. 4. The epoxy resin composition for sealing according to claim 1, wherein the mercapto group-containing silane compound has been hydrolyzed in advance. 5. The epoxy resin composition for sealing according to claim 1, wherein the mercapto group-containing silane compound has been hydrolyzed in advance and reacted with an epoxy resin. 6. The epoxy resin composition for sealing according to claim 1, further comprising an ethoxy compound of a linear primary alcohol having 18 or more carbon atoms. 7. A semiconductor device in which a semiconductor element is sealed with an epoxy resin composition, wherein the epoxy resin composition according to any one of claims 1 to 6 is used as the epoxy resin. Resin-encapsulated semiconductor device.