Resin paste for semiconductor and semiconductor device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a resin paste for adhering a semiconductor element such as an IC or LSI to a metal frame or the like.

【0002】

[Conventional technology]

In recent years, the degree of integration of semiconductor elements such as ICs has increased, and the size of semiconductor elements has increased. On the other hand, as a lead frame for a semiconductor device, a copper frame has come to be used for cost reduction because the 42 alloy frame that has been conventionally used is expensive. For semiconductors that have been conventionally used in the mounting process of adhering a semiconductor element to a lead frame, corresponding to a semiconductor device using such a large semiconductor element and a lead frame having a large thermal expansion coefficient such as a copper frame. Instead of the resin paste, in order to prevent cracks and warpage of the semiconductor element, a resin paste for semiconductors having a low elastic coefficient by blending a low stressing agent has been used. On the other hand, as the miniaturization, thinning, and narrowing of pitches of semiconductor devices are accelerating in response to the trend of miniaturization, weight reduction, and high functionality of electronic devices, the resin paste for semiconductors is used after absorbing moisture of the semiconductor devices. There is a strong demand for improvements in solder crack resistance and moisture resistance. In order to improve these reliability, it is necessary that the semiconductor element and the lead frame are in close contact with each other. However, in the conventional resin paste for semiconductors containing a low stress agent, a large amount of the low stress agent must be mixed in order to reduce the elastic modulus, and the lead frame or semiconductor element adheres to the semiconductor resin paste. Since the property is lowered, there is a problem that the reliability of the semiconductor device is not improved as expected.

【0003】

[Problems to be Solved by the Invention]

The present invention uses a highly reliable semiconductor resin paste that does not reduce adhesion, has a low elastic modulus, and does not cause peeling of the semiconductor resin paste layer in a solder crack resistance test after moisture absorption treatment, and uses the same. It provides the semiconductor device that was used.

【0004】

[Means for solving problems]

The present invention contains [1] (A) epoxy resin, (B) curing agent, (C) low stress agent, and (D) filler as essential components, and the low stress agent has a hydroxyl group at the molecular end. It is a compound that does not phase-separate and uniformly disperses when cured by mixing with an epoxy resin and a curing agent, and the low stress agent per 100 parts by weight of the epoxy resin is 3 to 100 parts by weight. The resin paste for semiconductors, [2] (C) low stress agent, which is characterized by the above, is selected from one or more compounds represented by the general formulas (1), (2), and (3). A resin paste for semiconductors according to item [1], [Chemical 4]

<img file="JP2002241584A_D0001.tif" />(R1 is a hydrogen atom or a methyl group and may be the same or different. R2 and R3 are alkylene groups having 1 to 6 carbon atoms and may be the same or different. A and b are 1 or more. It is an integer.

【0005】

[Chemical 5]

<img file="JP2002241584A_D0002.tif" />(R4 is a divalent group. C, d, e, f are integers greater than or equal to 1 and may be the same or different.

【0006】

[Chemical 6]

<img file="JP2002241584A_D0003.tif" />(R5 is a trivalent group. C, d, e, f, g, h are integers greater than or equal to 1 and may be the same or different.

[3] A semiconductor device, characterized in that it is manufactured by using the resin paste for a semiconductor according to the item [1] or [2].

【0007】

BEST MODE FOR CARRYING OUT THE INVENTION

The epoxy resin used in the present invention refers to all monomers, oligomers, and polymers having an epoxy group. For example, crystalline epoxy resins such as bisphenol A, bisphenol F, phenol novolac, cresol novolak and polyglycidyl ether, biphenyl type epoxy resin, stillben type epoxy resin, and hydroquinone type epoxy resin obtained by reaction with epichlorohydrin, butanediol di. An aliphatic epoxy resin such as glycidyl ether and neopentyl glycol diglycidyl ether, a heterocyclic epoxy resin such as diglycidyl hydantin, an alicyclic epoxy resin such as vinylcyclohexendioxide, dicyclopentadiendioxide, and alicyclic diepoxy adipate. Epoxy resin, dicyclopentadiene-modified phenol-type epoxy resin, triphenolmethane-type epoxy resin, naphthol-type epoxy resin, phenol-aralkyl-type epoxy resin, biphenyl-aralkyl-type epoxy resin, glycidylamine, etc. Can be used in combination. There are various types of epoxy resins depending on the molecular weight, but those having a small molecular weight and liquid at room temperature are preferable from the viewpoint of workability at the time of blending and viscosity after blending.

【0008】

When the epoxy resin is solid or semi-solid, or when it is liquid but has a high viscosity, it is preferable to use a reactive diluent having an epoxy group in combination. Examples of the reactive diluent include n-butyl glycidyl ether, versatic acid glycidyl ester, styrene oside, ethylhexyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, butyl phenyl glycidyl ether and the like. It is possible to use one type or a combination of multiple types.

【0009】

Examples of the curing agent used in the present invention include phenol resins, dicarboxylic acid dihydrazide compounds, imidazole compounds, aliphatic amines, aromatic amines, dicyandiamides, etc., and these may be used alone or in combination of two or more. Is possible.

【0010】

It is desirable that the phenol resin has two or more active hydrogen groups per molecule that react with the epoxy group and participate in cross-linking. Examples of such phenol resins include bisphenol A, bisphenol F, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol S, dihydroxydiphenyl ether, dihydroxybenzophenone, o-hydroxyphenol, m-hydroxyphenol, and the like. P-Hydroxyphenol, biphenol, tetramethylbiphenol, etilidenbisphenol, methylethylidenebis (methylphenol), cyclohexylidenebisphenol, and monovalent phenols such as phenol, cresol, xylenol and formaldehyde are mixed in a dilute aqueous solution under strong acidity. The initial condensate of phenol novolac resin, monovalent phenols and polyfunctional aldehydes such as achlorine and glioxal, and polyhydric phenols such as resorcin, catechol, hydroquinone and formaldehyde obtained by the reaction in Examples thereof include initial condensates under acidic conditions, and these can be used alone or in combination of two or more.

【0011】

Examples of the dicarboxylic acid dihydrazide compound include carboxylic acid dihydrazides such as adipic acid dihydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, and p-oxybenzoic acid dihydrazide, and these may be used alone or in combination of two or more. Is possible.

【0012】

Examples of the imidazole compound include 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2-phenyl-4. , 5-Dihydroxymethylimidazole, 2-C₁₁H₂₃-2,4-Diamino-6- {2-methylimidazole-(1)}-ethyl-S-triazine, which has been added with general imidazole such as imidazole, triazine or isocyanuric acid to impart storage stability, or its Examples thereof include isocyanate adducts, which can be used alone or in combination of two or more.

【0013】

The low stress agent (C) used in the present invention is a compound having a hydroxyl group at the molecular terminal and uniformly dispersing without phase separation when mixed with an epoxy resin and a curing agent and cured. , Not particularly limited, and these can be used alone or in combination of two or more. Further, one or more kinds selected from the compounds represented by the general formulas (1) to (3) are preferable. Specific examples of the general formulas (1) to (3) are shown below, but the present invention is not limited thereto.

[Chemical 7]

<img file="JP2002241584A_D0004.tif" />【0014】

[Chemical 8]

<img file="JP2002241584A_D0005.tif" />【0015】

[Chemical 9]

<img file="JP2002241584A_D0006.tif" />Even if the compound has a hydroxyl group at the molecular end, if it is phase-separated when mixed with an epoxy resin and a curing agent and cured, the blending amount is higher than that of a compound that is uniformly dispersed without phase separation. If the amount is not increased, the elastic modulus of the resin paste for semiconductors cannot be lowered and the adhesive strength is lowered, which is not preferable. The blending amount of the low stress agent (C) is preferably 3 to 100 parts by weight, more preferably 5 to 50 parts by weight, per 100 parts by weight of the epoxy resin. If it is less than 3 parts by weight, there is no effect of lowering the elastic modulus by blending a low stress agent, and if it exceeds 100 parts by weight, the adhesive strength is lowered, which is not preferable.

【0016】

Examples of the filler used in the present invention include an inorganic filler and an organic filler. Examples of the inorganic filler include metal powders such as gold powder, silver powder, copper powder and aluminum powder, molten silica, crystalline silica, silicon nitride, alumina, aluminum nitride and talc. Of these, metal powder is mainly used to impart conductivity and thermal conductivity. Examples of the organic filler include a silicone resin, a fluororesin such as polytetrafluoroethylene, an acrylic resin such as polymethylmethacrylate, and a crosslinked product of benzoguanamine or melamine and formaldehyde. These fillers preferably have a content of ionic impurities such as halogen ions and alkali metal ions of 10 ppm or less. Further, as the shape of the filler, for example, flakes, scales, resins, spheres and the like are used. The particle size of the filler used varies depending on the required viscosity of the resin paste for semiconductors, but it is usually preferable that the average particle size is 0.3 to 20 μm and the maximum particle size is about 50 μm. If the average particle size is less than 0.3 μm, the viscosity becomes high, and if it exceeds 20 μm, the resin component flows out during coating or curing, which may cause bleeding. If the maximum particle size exceeds 50 μm, when applying the resin paste for semiconductors with a dispenser, the outlet of the needle is blocked and continuous use for a long time is not possible. Further, a relatively coarse filler and a fine filler may be mixed and used, and various types and shapes may be appropriately mixed. Further, in order to impart the required properties, a filler other than the above may be used. Examples thereof include nanoscale fillers having a particle size of about 1 to 100 nm, composite materials of silica and acrylic, composite fillers of organic compounds and inorganic compounds such as those having a metal coating on the surface of organic fillers, and the like. .. As the filler of the present invention, a filler whose surface is previously treated with a silane coupling agent such as alkoxysilane, asyloxysilane, silazane, or organoaminosilane may be used.

【0017】

The resin paste for semiconductors of the present invention contains components (A) to (D) as essential components, but in addition to these, a curing accelerator, a silane coupling agent, a titanate coupling agent, a pigment, a dye, and an erasing agent are required. Additives such as foaming agents, surfactants and solvents can be appropriately added. The resin paste for semiconductors of the present invention can be obtained by a production method such as premixing components (A) to (D) and other additives, kneading with a roll or the like, and then defoaming under vacuum. .. A known method can be used to manufacture a semiconductor device using the resin paste for semiconductors of the present invention.

【0018】

[Example]

The present invention will be specifically described with reference to Examples. The blending ratio of each component shall be parts by weight. &lt;Examples 1 to 7&gt; Each component was kneaded with a roll according to the formulation shown in Table 1 and defoamed using a vacuum chamber to obtain a resin paste for a semiconductor. The obtained resin paste for semiconductors was evaluated by the following method. The results are shown in Table 1.

【0019】

&lt;Ingredients used&gt; Epoxy resin: Bisphenol A type epoxy resin (viscosity at 25 ° C 9000 mPa · s, epoxy equivalent 185) Reactive diluent: Phenylglycidyl ether Hardener: Phenolic novolak resin (hydroxyl equivalent 104), dicyandiamide Low stress agent: Compound represented by Eq. (4) [Chemical 10]

<img file="JP2002241584A_D0007.tif" />【0020】

Compound represented by formula (5) [Chemical 11]

<img file="JP2002241584A_D0008.tif" />【0021】

Compound represented by formula (6) [Chemical 12]

<img file="JP2002241584A_D0009.tif" />Inorganic filler: Silver powder: Particle size 0.1 to 50 μm, average particle size 3 μm, flakes. Silica: Average particle size 3 μm, maximum particle size 20 μm, spherical [0022]

&lt;Evaluation method&gt; -Viscosity: The value at 25 ° C and 2.5 rpm was measured using an E-type viscometer (3 ° cone). -Elastic modulus: A resin paste for semiconductors is applied on a Teflon (registered trademark) sheet to a width of 10 mm, a length of about 150 mm, and a thickness of 100 μm, cured in an oven at 200 ° C for 60 minutes, and then used with a tensile tester. The test length was 100 mm, the tensile speed was 1 mm / 60 seconds, 25 ° C, or 260 ° C, and the elastic modulus was calculated from the initial gradient of the obtained stress-strain curve. -Adhesive strength: A silicon chip of 5 mm x 5 mm was mounted on a copper frame using a resin paste for semiconductors, and cured at 200 ° C for 60 minutes using an oven. After curing, the thermal die shear strength at 25 ° C or 260 ° C was measured using a mount strength measuring device. -Compatibility: A mixture of epoxy resin, curing agent, and low stressing agent, 5 cm in a 50 mmφ aluminum cup.³It was put in and cured in an oven at 200 ° C for 60 minutes. The cured product was visually observed to confirm the presence or absence of phase separation. -Soldering resistance (peeling rate): A silicon chip (size 9.0 mm x 9.0 mm) is mounted on a lead frame (copper) using a semiconductor resin paste, and an oven is used in a nitrogen atmosphere at 200 ° C for 60 minutes. Hardened with. This lead frame is transfer molded using an epoxy resin encapsulant with an 80-pin QFP (package size 14 x 20 mm, thickness 2.0 mm) at a mold temperature of 175 ° C, injection pressure of 7.5 MPa, and curing time of 60 seconds. It was post-cured at 175 ° C for 8 hours. The obtained package was left to stand in an environment of 85 ° C. and a relative humidity of 85% for 168 hours, and then immersed in a solder bath at 260 ° C. for 10 seconds. A transmissive ultrasonic flaw detector is used to measure the total peeled area inside the package, and a reflective ultrasonic flaw detector is used to measure the peeled area between the chip and the epoxy resin encapsulant, and the lead frame and epoxy. The total value of the peeled area from the resin encapsulant was measured. Obtain (the peeling area of the die attach layer) = [(total peeling area in transmission)-(total peeling area in reflection)], and determine the peeling rate of the resin paste for semiconductors (peeling rate) = [ (Peeled area of die attach layer) / (Chip area) x 100], the average value of 5 packages was calculated and displayed in%.

【0023】

&lt;Comparative Examples 1 to 7&gt; Resin pastes for semiconductors were obtained in the same manner as in Examples according to the formulation shown in Table 2, and evaluated in the same manner as in Examples. The results are shown in Table 2. The details of the low stress agent used in the comparative example are shown below. Amine-terminated butadiene / acrylonitrile copolymer (viscosity at 25 ° C: 225 Pa · s, active hydrogen equivalent: 450, average molecular weight: 1300; hereinafter referred to as ATBN), epoxidized polybutadiene (viscosity at 25 ° C: 100 Pa · s, epoxy equivalent) 200, average molecular weight 1000) [table 1]

<img file="JP2002241584A_D0010.tif" />【0024】

[Table 2]

<img file="JP2002241584A_D0011.tif" />【0025】

[Effect of the invention]

According to the present invention, a semiconductor resin paste having an excellent reliability and a low elastic modulus, which does not reduce the adhesive strength at the time of heat and does not cause peeling of the semiconductor resin paste layer in the solder crack resistance test after the moisture absorption treatment, and the present invention. A semiconductor device using the above can be obtained.