JP4595301B2 - Resin paste for semiconductor and semiconductor device - Google Patents

Description

  The present invention relates to a highly reliable and highly heat conductive resin paste for bonding and fixing a semiconductor element such as an IC or LSI to a metal frame, a printed wiring board or the like.

  Recent advances in the electronics industry have evolved into transistors, ICs, LSIs, and super LSIs, and the integration of circuits in these semiconductor devices has increased rapidly, enabling mass production, and semiconductors using these. With the spread of products, improvement in workability and cost reduction in mass production have become important problems. Conventionally, a semiconductor element is usually bonded to a conductor such as a metal frame by an Au-Si eutectic method and then sealed with a hermetic seal to obtain a semiconductor product. However, in terms of workability and cost during mass production, a resin sealing method has been developed and is now generalized, and a resin paste, that is, a conductive paste, is taken up as an improvement of the Au-Si eutectic method in the mounting process. It came to be able to. In addition, with the increase in density and capacity of semiconductor elements, the resin paste itself is required to have the same conductivity and thermal conductivity as those of conventional solder metals.

As such a highly reliable conductive paste, a method of diluting a thermoplastic resin in an organic solvent and highly filling a metal filler such as silver powder to obtain a paste has been studied (for example, see Patent Document 1). In order to ensure high thermal conductivity and electrical conductivity, if you try to add metal filler as much as possible, the viscosity will increase, the coating workability will decrease, or the organic solvent added to reduce the viscosity will be scattered during heating, causing voids Thus, there are problems such as a decrease in the thermal conductivity of the connection part and an increase in electrical resistance.
JP-A-11-066956

  An object of the present invention is to provide a highly reliable conductive paste that has thermal conductivity and electrical conductivity comparable to solder and does not deteriorate semiconductor characteristics even in a high-temperature solder reflow process.

Such an object is achieved by the present invention described in the following [1] to [5].
[1] A resin paste for semiconductors containing (A) a thermosetting resin, (B) a curing agent, and (C) a filler as essential components, wherein the filler is silver powder and an average particle size subjected to metal plating 1.0 to 50 μm glass beads , the silver powder is contained in 70% by weight or more in the total resin paste, and the glass beads are contained in the total resin paste by 5% by weight or more. Resin paste.
[2] The semiconductor according to [1], wherein a weight ratio (silver powder / glass beads) of the silver powder and the glass beads contained in the filler is 86.7 / 13.3 to 81.1 / 18.9. Resin paste.
[3] The resin paste for semiconductors according to [1] or [2 ], wherein the thermosetting resin is made of at least one resin selected from an epoxy resin and a (meth) acrylate resin that are liquid at room temperature.
[4] The semiconductor resin paste according to any one of [ 1] to [3 ], wherein the metal plating on the surface of the glass beads is selected from the group consisting of gold, silver, copper, and nickel. .
[5] [1] to [4] The semiconductor device formed by fabricated using semiconductor resin paste according to any one of.

  According to the present invention, a highly reliable conductive paste having high thermal conductivity and high electrical conductivity and excellent reliability under high temperature and high humidity and coating workability can be obtained.

  The thermosetting resin and the curing agent of the present invention are not particularly limited, but are preferably an epoxy resin that is liquid at room temperature, an epoxy resin curing agent, an acrylate resin having an unsaturated double bond, and / or a methacrylate resin. It is desirable to be at least one resin system selected from radical initiators. The epoxy resin is not particularly limited as long as it is liquid, but examples include bisphenol A, bisphenol F, phenol novolac, polyglycidyl ether, butanediol diglycidyl ether obtained by reaction of cresol novolac and epichlorohydrin, neo Aliphatic epoxies such as pentyl glycol diglycidyl ether, heterocyclic epoxies such as diglycidyl hydantoin, alicyclic epoxies such as vinylcyclohexenedioxide, dicyclopentadiene dioxide, alicyclic diepoxy adipate, etc. Of these, one kind or a combination of plural kinds can be used. Further, even if it is solid at room temperature, it can be used in addition to the liquid epoxy as long as the properties are not impaired.

Further, the curing agent for the epoxy resin is not particularly limited. For example, carboxylic acid dihydrazide such as adipic acid dihydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, P-oxybenzoic acid dihydrazide, dicyandiamide, bisphenol A, Bisphenol F, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol S, dihydroxydiphenyl ether, dihydroxybenzophenone, o-hydroxyphenol, m-hydroxyphenol, p-hydroxyphenol, biphenol, tetramethylbiphenol, ethylidene bisphenol , Methyl ethylidene bis (methylphenol), hexylidene bisphenol, and phenol, cresol, xyleno Initial condensation of phenolic novolak resin obtained by reacting monohydric phenols such as alcohol with formaldehyde in dilute aqueous solution under strong acidity, monohydric phenols and polyfunctional aldehydes such as acrolein and glyoxal As an initial condensate under acidic conditions with polyphenols such as resorcin, catechol, hydroquinone and formaldehyde, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methyl imidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxy methyl imidazole, _2-C 11 _{H 23} - adds a generic imidazole or triazine and isocyanuric acid such as imidazole Give storage stability 2,4-diamino-6 {2-methylimidazole - (1)} - ethyl -s- triazine, also has its isocyanuric acid adduct can be used in combination with one or more of these.

  The acrylate resin and / or methacrylate resin having an unsaturated double bond used in the present invention is not particularly limited, but examples include alicyclic (meth) acrylic acid esters and aliphatic (meth) acrylic. Examples include acid esters, aromatic (meth) acrylic acid esters, aliphatic dicarboxylic acid (meth) acrylic acid esters, and aromatic dicarboxylic acid (meth) acrylic acid esters. The radical initiator is not particularly limited, but examples include methyl ethyl ketone peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, acetylacetone peroxide, 1,1-bis (t-butylperoxy) 3, 3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t- Butylperoxy) cyclohexane, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 1,1-bis (t-butylperoxy) cyclododecane, n-butyl 4,4-bis (T-butyl peroxyvalerate, 2,2-bis (t-butylpero B) Butane, 1,1-bis (t-butylperoxy) -2-methylcyclohexane, t-butyl hydroperoxide, P-menthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide , T-hexyl hydroperoxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, α, α′-bis (t-butylperoxy) diisopropylbenzene, t -Butyl cumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, isobutyryl peroxide, 3,5,5-trimethylhexanoyl Peroxide, octanoyl peroxide, lauroyl peroxide, cinnamic acid peroxide Id, m-toluoyl peroxide, benzoyl peroxide, diisopropyl peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-3-methoxybutylperoxydicarbonate, di-2-ethylhexylperoxide Oxydicarbonate, di-sec-butylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, α, α'-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneo Decanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t- Butyl peroxyneodecane , T-hexylperoxypivalate, t-butylperoxypivalate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, 1,1,3,3-tetramethyl Butylperoxy-2-ethylhexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethyl Hexanoate, t-butyl peroxyisobutyrate, t-butyl peroxymaleic acid, t-butyl peroxylaurate, t-butyl peroxy 3,5,5-trimethylhexanoate, t-butyl peroxy Oxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, , 5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyacetate, t-hexylperoxybenzoate, t-butylperoxy-m-toluoylbenzoate, t-butylperoxybenzoate, Bis (t-butylperoxy) isophthalate, t-butylperoxyallyl monocarbonate, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, etc., which are used alone or cured Two or more kinds can be mixed and used to control the property.

  Although it is essential that the paste of the present invention contains a filler, glass beads having an average particle diameter of 1.0 to 50 μm whose surface is metal-plated are contained in an amount of 5% by weight or more in the total resin paste. Things are desirable. If the content of the metal-plated glass beads is less than 5% by weight, the effects of high thermal conductivity and high conductivity become poor, which is not preferable. On the other hand, when the average particle size of the metal-plated glass beads is less than 1 μm, the paste viscosity is increased, and the coating workability is remarkably impaired. On the other hand, if it exceeds 50 μm, the coating property from the coating nozzle is extremely lowered, which is not preferable.

The metal plating on the glass bead surface used in the present invention is preferably selected from the group consisting of gold, silver, copper and nickel in view of high electrical conductivity.
The fillers other than the metal-plated glass beads used in the present invention are not particularly limited, such as inorganic fillers and organic fillers, but conductive fillers such as gold, silver, copper, and nickel are more preferable.

  In the resin paste in the present invention, additives such as a silane coupling agent, a titanate coupling agent, a pigment, a dye, an antifoaming agent, a surfactant, and a solvent are added within a range that does not impair the characteristics depending on the application if necessary. Can be used. As the production method of the present invention, for example, each component is premixed and kneaded using a three roll or the like to obtain a paste, and then dehydrated under vacuum.

The present invention will be specifically described with reference to examples. The blending ratio of each component is parts by weight.
<Examples 1-8, Comparative Examples 1-7>
Each component of the composition shown in Tables 1 and 2 and an inorganic filler were blended and kneaded with three rolls to obtain a resin paste. The resin paste was defoamed at 2 mmHg for 30 minutes in a vacuum chamber, and various performances were evaluated by the following methods.

<Used raw material components>
・ Bisphenol F type epoxy resin (BPF): Viscosity 5000 mPa · s, epoxy equivalent 170
・ Bisphenol A type epoxy resin (BPA): viscosity 6800mPa · s, epoxy equivalent 190
Reactive diluent: t-butylphenyl glycidyl ether: viscosity 400 mPa · s
・ Phenol hardener: Bisphenol F
-Latent curing agent: Dicyandiamide (DDA)
Imidazole compound: 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ)
・ Acrylate-terminated liquid polybutadiene (BAC-45, Osaka Organic Chemical Industry Co., Ltd.)
・ Epoxy-modified liquid polybutadiene (E-1800, Mitsubishi Oil Corporation)
・ Lauryl acrylate (LA)
・ Dicumyl peroxide (Perhexa 3M)
・ Silver powder
Flaky silver powder a1: average particle size 2 μm,
Flaky silver powder a2: Average particle size 5 μm
Silver-plated glass beads UBS-0010LAg (manufactured by Union Co., Ltd.): average particle size 7 μm
UBS-0030LAg (manufactured by Union Co., Ltd.): average particle size 18 μm
・ Glass beads UB-24M (manufactured by Union Co., Ltd.): average particle size 44 μm

<Evaluation method>
Viscosity: Using an E-type viscometer (3 ° cone), the values at 25 ° C., 0.5 rpm, and 2.5 rpm were measured at 25 ° C. to obtain the viscosity. The ratio of measured values at different rotational speeds was defined as a thixo index (TI).
Adhesive strength: A 2 × 2 mm silicon chip was mounted on a copper frame using a paste and cured in an oven at 170 ° C. for 30 minutes. After curing, the die shear strength during heating at 25 ° C. and 250 ° C. was measured using a mount strength measuring device.
Chlorine ion concentration: After applying a conductive paste in a Teflon (R) sheet and curing it at 170 ° C for 30 minutes, weigh approximately 2 g of a cured resin sample finely pulverized with a vibration mill, and add 20 ml of pure water. The liquid extracted under the conditions of 120 ° C. and 2.1 atm was filtered, and the amount of chloride ions was measured by ion chromatography, and converted to the resin content.
・ Moisture resistance reliability: Mounted on a lead frame of 16pin DIP (Dual Inline Package) with a paste element using a silicon chip surface with aluminum wiring, cured in an oven at 170 ° C for 30 minutes, and then bonded with gold wire Transfer molding with epoxy molding compound EME-6600CS manufactured by Sumitomo Bakelite Co., Ltd. under the condition of 175 ° C for 2 minutes, and then post-cured package at 175 ° C for 4 hours, then open after pressure cooker treatment (125 ° C, 2.5 atm) for 500 hours The defective rate was examined.
-Volume resistivity of the paste cured product: After printing on a preparation with a thickness of about 20 μm and a width of 0.5 mm, what was cured in an oven at 170 ° C. for 30 minutes was measured with a milliohm resistance measuring machine.
-Thermal conductivity of the cured paste: A disk-shaped specimen with a thickness of about 1 mm and a radius of 10 mm was prepared, and thermal diffusivity was measured using a laser flash method thermal constant measuring device LF / TCM FA815B manufactured by Rigaku Corporation. And the thermal conductivity is calculated from the specific heat and specific gravity.
-Dispensing property: 1000 dots were applied using a nozzle having an inner diameter of 0.1 mm with a pressure type automatic dispenser, and the number of dots that could be applied without clogging the nozzles was examined.

The evaluation results are shown in Tables 1 and 2.

  According to the present invention, a highly reliable conductive paste having high thermal conductivity and high electrical conductivity and excellent reliability under high temperature and high humidity and coating workability can be obtained. It is extremely useful as a resin paste that is bonded and fixed to a printed wiring board or the like.

Claims (4)

(A) A thermosetting resin, (B) a curing agent and (C) a resin paste for semiconductors containing essential components,
The filler comprises silver powder and metal plated glass beads having an average particle diameter of 1.0 to 50 μm, and a weight of silver powder / glass beads = 86.7 / 13.3 to 81.1 / 18.9 Including by ratio ,
The silver powder is contained in 70% by weight or more in the total resin paste,
The resin beads for semiconductor, wherein the glass beads are contained in the total resin paste in an amount of 5% by weight or more. The resin paste for a semiconductor according to claim 1, wherein the thermosetting resin comprises at least one resin selected from an epoxy resin and a (meth) acrylate resin that are liquid at room temperature. The resin paste for a semiconductor according to claim 1 or 2 , wherein the metal plating on the surface of the glass beads is selected from the group consisting of gold, silver, copper and nickel. The semiconductor device manufactured using the resin paste for semiconductors of any one of Claims 1 thru | or 3 .