JP2903610B2 - Adhesive composition and method for manufacturing semiconductor device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an adhesive composition and a method for manufacturing a semiconductor device.

(Prior Art) Conventionally, as a method of joining a semiconductor element to a lead frame (supporting member) when manufacturing a semiconductor device, (1)
There is a method of using an inorganic material such as a gold-silicon eutectic material as an adhesive, and (2) a method of dispersing silver powder in an organic material such as an epoxy resin or a polyimide resin to form a paste and using this as an adhesive. . However, the former method is costly and requires heat treatment at a high temperature of about 350 to 400 ° C. In addition, the adhesive is hard, and the chip may break down due to thermal stress. The latter method using a paste (hereinafter, referred to as a silver paste) has become mainstream. In this method, generally, a silver paste is applied to a lead frame by using a dispenser or a stamping machine, and then the semiconductor element is die-bonded and cured by heating to be joined.

Recently, with the increase in the size of integrated circuit (IC) devices and the increase in surface-mount type packages, (1) the heat dissipation of the devices, and (2) the material of the frame to improve the workability of the lead frame There is a growing tendency to change from conventional iron-nickel alloys to copper. In this case, when the paste is hardened and cooled due to the difference in linear expansion coefficient between the IC element (silicon) and the frame, thermal stress is generated at the time of cooling, and the warpage of the IC element increases.
Cracks tend to occur not only in the IC element but also in the die bonding material, which has the disadvantage of significantly reducing the reliability of the semiconductor device.

As a method for improving the above-mentioned disadvantage, a method for reducing the thermal stress by reducing the elastic modulus of the die bonding material is generally used.

Specific methods of the epoxy resin-based die bonding agent include (1) lowering the crosslink density by using a high molecular weight epoxy resin, (2) using a general-purpose epoxy resin (for example, bisphenol A type epoxy resin) and a carboxyl group at the terminal. In general, there are two methods of reacting an acrylonitrile-butadiene copolymer containing styrene and introducing a bone nucleus having rubber elasticity into the molecular chain. However, in both cases, the viscosity of the base epoxy increases and the die bonding material is used. Since stringing occurs at the time of application to the lead frame, the application speed must be significantly reduced, and the production efficiency decreases. In order to improve this, if a large amount of solvent is added to lower the viscosity of the base resin, the amount of the solvent scattered during curing will increase, and many voids will be generated in the die-bonding material, and the humidity resistance of the IC element will be reduced. Has the drawback of causing a decrease in

(Problems to be Solved by the Invention) An object of the present invention is to eliminate the drawbacks of the prior art, join a semiconductor element and a support member, and reduce the warpage of the semiconductor element to obtain a highly reliable semiconductor device. And a method for manufacturing a semiconductor device using the same.

(Means for Solving the Problems) The present invention relates to (1) an epoxy resin (A) having two or more epoxy groups in a molecule and having a viscosity at 25 ° C. of 5 Pa · s or less and two epoxy resins in a molecule. A product obtained by reacting the acrylonitrile-butadiene copolymer (B) having a carboxyl group in a molar ratio (A) / (B) of 85/15 to 60/40, (2) a novolak-type phenol resin, An adhesive composition containing (3) silver powder and (4) a silica-based filler having a maximum particle diameter of 0.1 μm or less, and a semiconductor element is bonded to a supporting member using the adhesive composition. The present invention relates to a method for manufacturing a semiconductor device.

The epoxy resin (A) having two or more epoxy groups in the molecule and having a viscosity of 5 Pa · s or less at 25 ° C. used in the present invention includes, for example, bisphenol F, bisphenol AD, etc. and epichlorohydrin. Epoxy resins derived from butadiene and peracetic acid, and aliphatic epoxy resins derived from glycols such as diethylene glycol and polypropylene glycol and epichlorohydrin. The viscosity of the epoxy resin at 25 ° C of 5 Pa · s or less is 5 Pa · s
If it exceeds acrylonitrile having a carboxyl group
This is because the viscosity of the reaction product with the butadiene copolymer increases, the amount of the solvent used for adjusting the viscosity increases, and many voids are generated in the die bonding material. Examples of the acrylonitrile-butadiene copolymer (B) having two or more carboxyl groups in the molecule include commercially available Hiker CTBN1300 × 9 and CTBN1300 manufactured by Ube Industries, Ltd.
× 13 is raised. Epoxy resin and acrylonitrile
The reaction product of the butadiene copolymer can be easily obtained by, for example, placing triphenylphosphine as a catalyst with both of them in a glass flask, heating to 110 to 130 ° C., and reacting with stirring for 30 to 60 minutes.

The reaction ratio between the epoxy resin and the acrylonitrile-butadiene copolymer was (A) / (B) in a molar ratio of 85/15.
~ 60/40 range. When the ratio of the acrylonitrile-butadiene copolymer is less than 15, the effect of reducing the warpage of the device after bonding the semiconductor device to the support member is small.
On the other hand, if it exceeds 40, the viscosity of the reaction product becomes high, stringing tends to occur when the adhesive is applied to the support member, and the adhesive strength between the semiconductor element and the support member decreases.

The novolak type phenolic resin used in the present invention is a condensate of phenol and its derivative and formaldehyde in the presence of an acidic catalyst, and the type thereof is not limited.

The amount of the novolak type phenolic resin is preferably adjusted so that the hydroxyl group reacts with one epoxy group of the above reaction product at a ratio of 0.8 to 1.0.

The shape and particle size of the silver powder used in the present invention are not particularly limited, and the amount of the silver powder can be adjusted as desired. The preferred average particle size of the silver powder is 1 to 5 μm.
The preferred amount is 60% of the total weight of the adhesive composition.
~ 80% by weight.

The silica-based filler having a maximum particle size of 0.1 μm or less used in the present invention is used to prevent stringing of the adhesive. For example, Aerosil manufactured by Nippon Aerosil Co., Ltd. may be used. 202, and RY-200
The addition amount is preferably 2% by weight or less based on the total weight of the adhesive composition from the viewpoints of adhesive coating properties and discharge properties.

In the present invention, a general reactive diluent and a solvent can be used for adjusting the viscosity of the adhesive, and a curing accelerator such as a coupling agent, an antifoaming agent, a nomidazole, and a tertiary amine can be added. Agents may be used.

(Examples) Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 0.85 mol of bisphenol F type epoxy resin having an epoxy equivalent of about 175 (trade name, manufactured by Toto Kasei Co., Ltd., viscosity: 3.2 Pa · s) and an acrylonitrile-butadiene copolymer having an acid equivalent of 1750 (trade name, manufactured by Ube Industries, Ltd. CTBN1300 × 13) 0.15 mol, triphenylphosphine 0.05% by weight based on the total amount of the above epoxy resin and acrylonitrile-butadiene copolymer (the same applies in the following examples) is placed in a flask and stirred at 120 ° C. for 30 minutes. Reacted. To 200 g of the reaction product, 170 g of butyl cellosolve and 37.6 g of a novolak-type phenol resin having a hydroxyl equivalent of 106 (trade name, manufactured by Meiwa Kasei Co., Ltd., H-1) were dissolved in a flask at 80 ° C. for 30 minutes to prepare a base resin for an adhesive. Obtained.

Example 2 0.7 mol of bisphenol F type epoxy resin having an epoxy equivalent of about 175 (trade name, manufactured by Toto Kasei Co., Ltd., viscosity: 3.2 Pa · s) and an acrylonitrile-butadiene copolymer having an acid equivalent of 1750 (trade name, manufactured by Ube Industries, Ltd. CTBN1300 × 13) 0.3 mol and 0.05% by weight of triphenylphosphine were placed in a flask and reacted under the same conditions as in the examples. To 200 g of the obtained reaction product, 200 g of butyl cellosolve and 14.8 g of a novolak-type phenol resin having a hydroxyl equivalent of 106 (trade name, manufactured by Meiwa Kasei Co., Ltd., H-1) were dissolved in a flask at 80 ° C. for 30 minutes to prepare an adhesive. A base resin was obtained.

Example 3 A bisphenol AD epoxy resin having an epoxy equivalent of about 170 (trade name, manufactured by Mitsui Petrochemical Co., Ltd., R1710 viscosity 1.8 Pa · s) was used.
0.8 mol, 0.2 mol of an acrylonitrile-butadiene copolymer having an acid equivalent of 1750 (trade name, CTBN1300 × 13, manufactured by Ube Industries, Ltd.) and 0.05% by weight of triphenylphosphine were placed in a flask and reacted under the same conditions as in the examples. 170 g of butyl cellosolve was added to 200 g of the obtained reaction product, and a novolak type phenol resin having a hydroxyl equivalent of 106 (trade name, H-1 manufactured by Meiwa Kasei Co., Ltd.)
25.5 g was melted in a flask at 80 ° C. for 30 minutes to obtain a base resin for an adhesive.

To 30 g of the base resin obtained in Examples 1 to 3, 0.1 g of 2-ethyl 4-methylimidazole, 70 g of silver powder (trade name, TCG-1 manufactured by Tokuri Chemical Co., Ltd.) and Aerosil RY manufactured by Nippon Aerosil Co., Ltd.
1 g of -200 (maximum particle size, 0.06 μm) was added and kneaded with a crusher manufactured by Ishikawa Plant for 60 minutes to prepare a paste-like adhesive composition.

Comparative Example 1 A 200 g of bisphenol F type epoxy resin having an epoxy equivalent of about 175 (trade name, manufactured by Toto Kasei Co., Ltd., viscosity: 3.2 Pa · s) is a 70 g butyl cellosolve, a novolak type phenol resin having a hydroxyl equivalent of 106 (trade name, manufactured by Meiwa Kasei Co., Ltd. H-1) 60 g was melted in a flask at 80 ° C. for 30 minutes to obtain a base resin for an adhesive.

Comparative Example 2 An acrylonitrile-butadiene copolymer (trade name, manufactured by Ube Industries, Ltd.) having a molar ratio of 0.5 mol of bisphenol F type epoxy resin having an epoxy equivalent of about 175 (trade name, manufactured by Toto Kasei Co., Ltd., viscosity: 3.2 Pa · s) and an acid equivalent of 1750 CTBN1300 × 13) 0.5 mol was reacted under the same conditions as in Example 1. 200 g of the obtained reaction product
In a flask, 200 g of butyl cellosolve and 6.4 g of a novolak-type phenol resin having a hydroxyl equivalent of 106 (trade name, H-1 manufactured by Meiwa Kasei Co., Ltd.) were dissolved in a flask at 80 ° C. for 30 minutes to obtain a base resin for an adhesive.

2-ethyl 4 was added to 30 g of the base resin obtained in Comparative Examples 1 and 2.
−Methylimidazole 0.1g, silver powder (Tokuriki Chemical trade name, TC
G-1) 70 g and Aerosil RY-200 1 g manufactured by Nippon Aerosil Co., Ltd.
And kneaded with a crusher manufactured by Ishikawa Plant for 60 minutes.
A paste-like adhesive composition was obtained.

Comparative Example 3 To 30 g of the base resin of Example 2, 0.1 g of 2-ethyl 4-methylimidazole and silver powder (trade name of TCG-
1) 70 g was added and kneaded with a crusher manufactured by Ishikawa Plant for 60 minutes to obtain a paste adhesive composition.

Test Examples 1 to 3 The adhesive compositions obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were each filled in a syringe, and the adhesive strength, stringiness, and warpage of the silicone wafer were evaluated.

1. Evaluation of adhesive strength 2.5 mm x 2.5 on silver lead frame 1 shown in Fig. 1
About 120 μg of the adhesive composition 4 obtained above was applied onto the silver-coated island 2 mm as shown in FIG.
A silicon wafer 3 of 0 mm × 2.0 mm × 0.25 mmt is placed, and then pressed with tweezers so that the adhesive composition 4 slightly protrudes around the wafer 3, and then cured in an oven heated to 180 ° C. for 60 minutes. A test piece was obtained. Using a push-pull gauge (manufactured by Iiko Co., Ltd.), the test piece was peeled at 23 ° C. and 300 ° C., and the adhesive force was measured by peeling off the wafer.

2. Evaluation of stringiness The adhesive composition of 5 mg (applied 16 points at 310 μg / point) was applied to a copper frame 5 (island portion 6) having a silver-coated surface shown in FIG. 3, and then a syringe was applied at a rate of 20 cm / sec. The number of tests which evaluated the stringing property by measuring the number of the pastes which pulled up at a speed and pulled down sideways after the thread was drawn was set to 5 (80 points coating).

3. Evaluation of warpage of silicon wafer As shown in FIG. 3, after applying 5 mg of an adhesive composition (200 μg / point, 25 points applied) to a copper frame 5 (island portion 6) having a silver-plated surface, 10 mm × 10 mm A 0.35 mmt silicon wafer is pressed and cured in an oven heated to 180 ° C for 60 minutes, and the amount of warpage of the wafer immediately after curing and after heat treatment on a 300 ° C hot plate for 20 seconds is measured. It was measured with a sagmeter (DEKTAKIIA, manufactured by Nippon Vacuum Engineering Co., Ltd.).

 Table 1 summarizes the various evaluation results described above.

(Effect of the Invention) According to the adhesive composition of the present invention, even when a copper-based lead frame having a different expansion coefficient from that of a semiconductor element is used, the warpage of the semiconductor element can be significantly reduced. The semiconductor device can be manufactured without increasing the speed of a conventional coating process while improving the performance.

[Brief description of the drawings]

FIG. 1 is a schematic view of an adhesive strength evaluation frame, and FIG.
FIG. 3 is a cross-sectional view of a frame to which a wafer is bonded, and FIG. DESCRIPTION OF SYMBOLS 1 ... Copper lead frame 2 ... Island part with silver plating 3 ... Silicon wafer 4 ... Adhesive composition 5 ... Copper frame with surface silver plating 6 ... Island part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H01L 21/52 H01L 21/52 E // (C08K 3/00 3:08 3:36) (58) Field surveyed (Int. Cl ^6, DB name) C09J 163/00 -. 163/10 H01L 21/52 C08G 59/14 C08G 59/62 C08L 63/00 - 63/10 C08K 3/08 C08K 3/36

Claims (2)

(57) [Claims] 1. An epoxy resin (A) having two or more epoxy groups in a molecule and having a viscosity at 25 ° C. of 5 Pa · s or less and an acrylic resin having two or more carboxyl groups in a molecule. A product obtained by reacting a nitrile-butadiene copolymer (B) at a molar ratio of (A) / (B) of 85/15 to 60/40, (2) a novolak-type phenolic resin, (3) silver powder and (4) An adhesive composition containing a silica filler having a maximum particle size of 0.1 μm or less. 2. A method for manufacturing a semiconductor device, comprising: bonding a semiconductor element to a supporting member using the adhesive composition according to claim 1.