JP4380564B2 - Resin composition and semiconductor device produced using resin composition - Google Patents

Description

  The present invention relates to a resin composition and a semiconductor device manufactured using the resin composition.

While lead elimination from semiconductor products is being promoted as part of environmental measures, there is an increasing number of cases where lead frame plating is changed to Ni-Pd for the purpose of lead removal from exterior plating of semiconductor products. Here, Ni—Pd plating is performed by thin gold plating (gold flash) for the purpose of improving the stability of the Pd layer on the surface. However, due to the smoothness of the Ni—Pd plating itself and the presence of gold on the surface, ordinary silver is used. Compared with a plated copper frame or the like, the adhesive strength is reduced. Also, since lead-free solder is used as the solder for mounting on the substrate, the reflow temperature needs to be higher than in the case of tin-lead solder. Due to an increase in stress due to a decrease in adhesive force and an increase in reflow temperature, the constituent material of the semiconductor product needs to have higher reflow resistance because peeling and cracks are likely to occur in the semiconductor product during reflow.
Therefore, a material excellent in adhesion to a Ni-Pd plating frame than a conventionally used die attach paste (see, for example, Patent Document 1) and at the same time having a low elastic modulus and low stress is desired. There was nothing satisfactory.
JP 2000-273326 A

  The present invention is excellent in reliability such as solder crack resistance and the like using a resin composition exhibiting good adhesion to a Ni-Pd plating frame and having a low elastic modulus and the present invention as a die attach material for semiconductors. A semiconductor device is provided.

Such an object is achieved by the present invention described in the following [1] to [9].
[1] A resin composition for adhering a semiconductor element, wherein (A) a filler, (B) a compound represented by the general formula (1), (C) a compound represented by the general formula (2), (D) A compound having at least two phenolic hydroxyl groups in one molecule, (E) an imidazole compound having a melting point of 180 ° C. or higher as an essential component, and a ratio of the compound (B) compound (C) in a molar ratio of 1/3 or higher, 3 / 1 or less, The resin composition characterized by the above-mentioned.

[2] The resin composition according to item [1], wherein the compound (B) is at least one selected from diglycidyl bisphenol A and diglycidyl bisphenol F.
[3] The resin composition according to [1] or [2], wherein the compound (C) is dimethylolcyclohexanediglycidyl ether.
[4] The resin composition according to item [1], [2] or [3], wherein the compound (D) is at least one selected from bisphenol A, bisphenol F, or derivatives thereof.
[5] The resin according to item [1], [2], [3] or [4], wherein the imidazole compound (E) is an adduct of 2-methylimidazole and 2,4-diamino-6-vinyltriazine. Composition.
[6] The resin composition according to item [1], [2], [3] or [4], wherein the imidazole compound (E) is 2-phenyl-4-methyl-5-hydroxymethylimidazole.
[7] The resin composition according to any one of [1] to [6], wherein the filler (A) is silver powder.
[8] The resin composition according to item [7], wherein the filler (A) is silver powder and is contained in the resin composition in an amount of 70% by weight to 90% by weight.
[9] A semiconductor device manufactured using the resin composition according to any one of [1] to [8] as a die attach material.

  Since the resin composition of the present invention exhibits a good adhesive force with a Ni-Pd plating frame and has a low elastic modulus and a good low stress property, the present invention has been used so far as a die attach material. It is possible to provide a highly reliable semiconductor device that is not present.

The present invention relates to a filler (A), a compound (B) represented by the general formula (1), a compound (C) represented by the general formula (2), a compound having at least two phenolic hydroxyl groups in one molecule ( D) An imidazole compound (E) having a melting point of 180 ° C. or higher is an essential component, and by limiting the molar ratio of the compound (B) to the compound (C), the Ni—Pd plating frame and good adhesion and elastic modulus The resin composition which has low and favorable low-stress property is provided.
Hereinafter, the present invention will be described in detail.

  In the present invention, as filler (A), metal powder such as silver powder, gold powder, copper powder, aluminum powder, nickel powder and palladium powder, ceramic powder such as alumina powder, titania powder, aluminum nitride powder and boron nitride powder, polyethylene powder Polymer powders such as polyacrylate powder, polytetrafluoroethylene powder, polyamide powder, polyurethane powder, and polysiloxane powder can be used. When the resin composition is used, it may be discharged using a nozzle. Therefore, in order to prevent nozzle clogging, the average particle size is preferably 30 μm or less, and it is preferable that there are few ionic impurities such as sodium and chlorine. In particular, silver powder is preferably used when electrical conductivity and thermal conductivity are required. If it is the silver powder currently marketed for electronic materials normally, reduced powder, atomized powder, etc. can be obtained, and as an average particle diameter, an average particle diameter is 1 micrometer or more and 30 micrometers or less. In this range, the viscosity of the resin composition does not become too high and nozzle clogging does not occur during dispensing. Note that silver powder for non-electronic materials may contain a large amount of ionic impurities. The shape is not particularly limited, such as flakes and spheres, but preferably flakes are used and are usually contained in the resin composition in an amount of 70 to 90% by weight. In this range, the conductivity is good and the viscosity of the resin composition does not become too high.

  In the present invention, the compound (B) represented by the general formula (1) and the compound (C) represented by the general formula (2) are used. The compound (B) is generally used as a diglycidyl ether of bisphenols, but when only the compound (B) is used, the cured product has a high elastic modulus and is disadvantageous in terms of stress. On the other hand, since the glycidyl group is aliphatic in the compound (C), it is often used for curing with a cationic polymerization system or an acid anhydride, but in the case of a cationic polymerization system, the cationic polymerization catalyst remaining in the cured product This residue is not preferred because it deteriorates the moisture resistance of the semiconductor, and the acid anhydride curing system is not preferred because it is susceptible to hydrolysis and the moisture resistance of the cured product is not good. For this reason, in this invention, although the compound (D) which has at least two phenolic hydroxyl groups in 1 molecule is used as a hardening | curing agent, this can acquire favorable moisture resistance, when a compound (D) is used as a hardening | curing agent. Because. Here, when the compound (D) is used as a curing agent, the compound (C) has poor reactivity and cannot obtain sufficient cured product characteristics when used alone. Therefore, in order to compensate for the high modulus of elasticity which is a defect of the compound (B) and the low reactivity which is a defect of the compound (C), the molar ratio of the compound (B) and the compound (C) is 1/3 or more and 3/1 or less. It is necessary to use in. In this range, the elastic modulus is low, and sufficient cured product characteristics (adhesiveness with Ni—Pd plating frame, reflow resistance) can be obtained.

  It is preferable that the compounds (B) and (C) have few ionic impurities such as sodium and chlorine. Preferred examples of the compound (B) include diglycidyl bisphenol A, diglycidyl bisphenol F, and substituted products thereof that are commercially available for electronic materials. Preferable compound (C) includes dimethylolcyclohexane diglycidyl ether.

In the present invention, the compound (D) having at least two phenolic hydroxyl groups in one molecule is used as a curing agent, and as described above, by using the compound (D), good adhesion and moisture resistance can be obtained. It is because it is obtained. In the case of a compound having one phenolic hydroxyl group in one molecule, since a crosslinked structure cannot be taken, the properties of the cured product deteriorate and it cannot be used. The number of phenolic hydroxyl groups in one molecule can be used as long as it is 2 or more. However, the number of phenolic hydroxyl groups is preferably 2 or more and 5 or less. In the case of this range, the molecular weight is not increased, the viscosity of the resin composition is not increased, and the properties during dispensing are improved. More preferably, the number of phenolic hydroxyl groups in one molecule is two or three. Examples of such compounds include bisphenols such as bisphenol F, bisphenol A, and biphenol and derivatives thereof, trifunctional phenols such as tri (hydroxyphenyl) methane and tri (hydroxyphenyl) ethane, and derivatives thereof, phenol novolac, and cresol novolac. Examples of the phenol formaldehyde resin include dinuclear or trinuclear main ones or derivatives thereof, which are contained in an amount of 5% by weight to 70% by weight with respect to the total of the compound (B) and the compound (C).
Further, the number of functional groups is preferably 2. This is because when a bifunctional curing agent is used, the crosslink density of the cured product does not increase, resulting in a low elastic modulus.

  In the present invention, an imidazole compound (E) having a melting point of 180 ° C. or higher is used. This is necessary as a curing agent for the compound having a glycidyl group, and when the melting point is lower than 180 ° C., the storage stability at room temperature is deteriorated, so that it is further limited. Particularly preferred compounds are adducts of 2-methylimidazole and 2,4-diamino-6-vinyltriazine or 2-phenyl-4-methyl-5-hydroxymethylimidazole. These compounds are used in an amount of 0.5% by weight or more and 20% by weight or less based on the total of the compound (B) and the compound (C). In this range, good cured product characteristics can be obtained. A more preferable blending ratio is 1% by weight or more and 10% by weight or less.

In the present invention, a diluent can be used as necessary. The diluent is a compound used for the purpose of lowering the viscosity of the resin composition, and representative examples thereof include monofunctional aromatic glycidyl ethers such as phenyl glycidyl ether and cresyl glycidyl ether, and aliphatic glycidyl ethers. It is done.
Moreover, it is also possible to use reaction catalysts, such as a phosphorus type and an amine type, as needed, and additives, such as a coupling agent, an antifoamer, and surfactant, can be used.
The resin composition of the present invention can be produced, for example, by premixing the components, kneading using three rolls, and degassing under vacuum.

  As a method of manufacturing a semiconductor device using the resin composition of the present invention, a known method can be used. For example, using a commercially available die bonder, the resin composition is dispensed on a predetermined portion of the lead frame, and then the chip is mounted and heat-cured. Then, a semiconductor device is manufactured by wire bonding and transfer molding using an epoxy resin. Alternatively, it is also possible to use a method in which a resin composition is dispensed on the back surface of a chip such as a flip chip BGA that is sealed with an underfill material after flip chip bonding, and a heat radiating component such as a heat spreader or lid is mounted and cured.

[Examples 1 to 4]
The filler (A) is flaky silver powder (hereinafter referred to as silver powder) having an average particle diameter of 8 μm and a maximum particle diameter of 30 μm, and the compound (B) is diglycidyl bisphenol A (epoxy equivalent of 180) obtained by reaction of bisphenol A and epichlorohydrin. , Liquid at room temperature, R ¹ , R ² , R ⁴ , R ⁵ in the general formula (1) are —H, R ³ is —C (CH ₃ ) ₂ —, hereinafter referred to as compound B) as compound (C) Dimethylolcyclohexane diglycidyl ether (manufactured by Tohto Kasei Co., Ltd., ZX-1658, epoxy equivalent 130-140, R ⁶ , R ^{7 in} formula (2) is H, n is 1, and compound C) is converted to compound ( D) is bisphenol F (Dainippon Ink Industries, Ltd., DIC-BPF, hydroxyl equivalent 100, hereinafter referred to as compound D), and compound (E) is 2-methylimidazole and Adduct of 2,4-diamino-6-vinyltriazine (Curazole 2MZ-A: manufactured by Shikoku Chemicals Co., Ltd., melting point 248-258 ° C., hereinafter referred to as compound E1) and 2-phenyl-4-methyl-5-hydroxymethyl Imidazole (Cureazole 2P4MHZ: manufactured by Shikoku Chemicals Co., Ltd., melting point 191-195 ° C., hereinafter referred to as compound E2) was used.
Table 1 shows cresyl glycidyl ether (epoxy equivalent 185, hereinafter referred to as CGE), dicyandiamide (hereinafter referred to as DDA), and silane coupling agent having a glycidyl group (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403E, hereinafter referred to as epoxy silane). The resin composition was obtained by mix | blending, knead | mixing using 3 rolls, and defoaming. The blending ratio is parts by weight.

[Comparative Examples 1-4]
The resin composition was obtained in the same manner as in Example 1 by blending at the ratio shown in Table 1. In Comparative Example 4 , 2-methylimidazole (Cureazole 2MZ: manufactured by Shikoku Chemicals Co., Ltd., melting point: 137 to 145 ° C.
The following compound X) was used.

Evaluation method / storability (viscosity change rate): Using an E-type viscometer (3 ° cone), the values at 25 ° C. and 2.5 rpm were measured immediately after preparing the resin composition and after leaving at 25 ° C. for 48 hours. The viscosity change rate after 48 hours was regarded as storage stability, and the case where the viscosity change rate was less than 20% was regarded as acceptable. The unit of viscosity change rate is%.
Adhesive strength: Using a resin composition, a 6 × 6 mm silicon chip was mounted on a Ni-Pd frame flashed with gold and cured in an oven at 175 ° C. for 30 minutes. After curing and after moisture absorption (85 ° C., 85%, 72 hours), the hot die shear strength at 260 ° C. was measured using an automatic adhesive force measuring apparatus. The case where the die shear strength when heated at 260 ° C. was 30 N / chip or more was regarded as acceptable. The unit of adhesive strength is N / chip.
Elastic modulus: A film-like test piece of 4 × 20 × 0.1 mm was prepared using the resin composition (curing condition: 175 ° C. for 30 minutes), and in a tensile mode with a dynamic viscoelasticity measuring machine (DMA). Measurements were made. The measurement conditions are as follows.
Measurement temperature: room temperature to 300 ° C
Temperature increase rate: 5 ° C / min Frequency: 10Hz
Load: 100mN
The storage elastic modulus at 25 ° C. was regarded as the elastic modulus, and the case of 5000 MPa or less was regarded as acceptable. The unit of elastic modulus is MPa.

Reflow resistance: Using the resin composition shown in Table 1, the following substrate (lead frame) and silicon chip were cured and bonded at 175 ° C. for 30 minutes. The die-bonded lead frame is sealed with a sealing material (Sumicon EME-7026, manufactured by Sumitomo Bakelite Co., Ltd.) to form a semiconductor device (package), and moisture absorption treatment is performed at 60 ° C. and a relative humidity of 60% for 192 hours, followed by IR reflow. Treatment (260 ° C., 10 seconds, 3 reflows) was performed. The degree of peeling of the treated package was measured with an ultrasonic flaw detector (transmission type). The case where the peeling area of the die attach part was less than 10% was regarded as acceptable. The unit of peeling area is%.
Package: QFP (14 x 20 x 2.0 mm)
Lead frame: Ni-Pd frame flashed with gold Chip size: 6 x 6 mm
Resin composition curing conditions: 150 ° C. for 15 minutes in oven

  Since the resin composition of the present invention exhibits a good adhesive force with the Ni-Pd plating frame and has a low elastic modulus and an excellent low stress property, the use of the present invention as a die attach material results in unprecedented high reliability. It can be suitably used for the semiconductor device.

Claims (9)

A semiconductor die attach paste for adhering a semiconductor element, wherein (A) a filler, (B) a compound represented by general formula (1), (C) a compound represented by general formula (2), (D) 1 A compound having at least two phenolic hydroxyl groups in the molecule, (E) an imidazole compound having a melting point of 180 ° C. or higher is an essential component, and the ratio of compound (B) to compound (C) is 1/3 or higher in terms of molar ratio. / 1 or less die attach paste for semiconductors .

The die attach paste for semiconductor according to claim 1, wherein the compound (B) is at least one selected from diglycidyl bisphenol A and diglycidyl bisphenol F. 3. The compound (C) is dimethylolcyclohexane diglycidyl ether.
The die attach paste for semiconductor as described. The die attach paste for semiconductor according to claim 1, 2 or 3, wherein the compound (D) is at least one selected from bisphenol A, bisphenol F or derivatives thereof. 5. The die attach paste for semiconductor according to claim 1, wherein the imidazole compound (E) is an adduct of 2-methylimidazole and 2,4-diamino-6-vinyltriazine. The die attach paste for semiconductor according to claim 1, 2, 3 or 4, wherein the imidazole compound (E) is 2-phenyl-4-methyl-5-hydroxymethylimidazole. The die attach paste for semiconductor according to any one of claims 1 to 6, wherein the filler (A) is silver powder. The die attach paste for semiconductor according to claim 7, wherein the filler (A) is silver powder and is contained in the resin composition in an amount of 70 wt% to 90 wt%. A semiconductor device manufactured by using the die attach paste for semiconductor according to claim 1 as a die attach material.