JPH01101363A - Epoxy resin composition and semiconductor device using said resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition giving a sealed product having lowered linear expansion coefficient and elastic modulus while suppressing the generation of thermal stress, by compounding an epoxy resin with an inorganic filler having specific double coating layers. CONSTITUTION:An epoxy resin is compounded with an inorganic filler having the 1st coating layer composed of at least one coupling agent selected from silane coupling agent, titanate coupling agent, aluminum chelate coupling agent and zircoaluminate coupling agent and the 2nd coating layer composed of an elastomer having an elastic modulus lower than that of the epoxy resin. The elastomer is an organopolysiloxane having a molecular weight of >=5,000 and has a thickness of >=0.01mum. The inorganic filler is fused silica.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides an epoxy resin-based molding material composition for semiconductor encapsulation that generates less thermal stress, and a molding material using the composition.
The present invention relates to an upper sealed conductor device.

[Conventional technology]

There are two types of exterior packaging for semiconductor devices such as transistors, ICs, LSIs, and VL8Is: a hermetic type that uses metal, glass, ceramics, etc., and a resin-sealed type that uses epoxy resin as the mainstream.

The former has excellent airtightness, but is very expensive. On the other hand, the latter can be produced extremely cheaply through mass production, and in recent years, advances in materials such as semiconductor elements and sealing resins, as well as manufacturing technology, have significantly improved the reliability of semiconductor products. More than 80 units are resin-sealed by transfer molding using thermosetting resin, mainly epoxy resin.

However, as the degree of integration of semiconductors improves year by year, chip sizes are becoming larger and interconnections are becoming finer and more multi-layered. On the other hand, when looking at the exterior package, the package size is becoming smaller and thinner due to higher density and automation of packaging, and the package shape is also changing from the conventional DIP (Dual Inline Package).
QFP [Quad Flat Package (Quaa pxatPackage)], 5o
p (Small Outline J-bended Package
Package ) ], PLCC [Plastic Leather Chip Carrier
dedChip Carrier) and other surface mount plastic packages.

With changes in the degree of integration, package size, package shape, mounting method, etc., the surface of the chip has become more delicate, and the thickness of the package seal has become significantly thinner. Also, the t1 package is exposed to higher temperatures than before when it is mounted. Therefore, if the encapsulated product is subjected to thermal stress, cracks may occur in the encapsulating resin due to the thermal stress caused by the differences in thermal expansion coefficients of the encapsulating resin, chip, frame, etc. that make up the semiconductor device wLK. This causes cracks in the chip and the passivation film formed on the chip surface, causing disconnections, short circuits, and misalignment of wiring on the chip surface, causing variations in device characteristics and reduction in reliability. That has become a problem. During this time, the package mounting method shifted from the bottle insertion method to the surface mount method, and the package became exposed to higher temperatures than before during mounting, making the seal layer an important issue.〇Resin Thermal stress generated in a sealed semiconductor device is caused by the difference in thermal expansion coefficient of each constituent material as described above. /?
! If the thermal form and tensile coefficient of r-structure reporting materials, especially sealing resins, can be reduced, thermal stress can be significantly reduced.

In general, sealing resins contain an inorganic filler whose thermal expansion coefficient is smaller than that of the resin for the purpose of reducing the thermal expansion coefficient. Just increase it. However, there is a problem in that increasing the filler content by 1 i-t increases the viscosity of the resin composition, lowering the fluidity and making the sealing work difficult. As a countermeasure, Special Publication No. 50-18520 and No. 5M-2
As described in each publication of No. 0541, a method has been proposed in which an inorganic filler having a specific particle size distribution is used to increase the filler content without significantly increasing the viscosity of the resin composition. However, even if such a method is used, the phenol-curing epoxy resin composition currently widely used for resin encapsulation of semiconductors has a high viscosity, making it difficult to mix the filler. It was difficult to increase the coefficient of thermal expansion, and it was not possible to significantly reduce the coefficient of thermal expansion. The reason for this is that conventionally, for such applications, fillers with angular shapes made by mechanically crushing raw stones have been used, resulting in low density optical density and increased viscosity of the resin composition. It is presumed that the company was susceptible to a decline in liquidity.

In order to solve this problem, it is generally said that the shape of the filler should be made spherical. However, spheroidizing fused silica, which has traditionally been widely used in semiconductor encapsulation resins, has not been industrially produced, and this method has not been adopted in practice.

However, Special Publication No. 60-26505 and No. 60-401
As disclosed in each publication No. 88, recently, q! Ra! A technology for industrially spheroidizing inorganic fillers has been established, and it is possible to increase the filler without increasing the viscosity or decreasing the fluidity of the resin composition, thereby achieving a thermal expansion coefficient of the sealing resin. It is now possible to reduce However, it is difficult to make the thermal expansion coefficient of the encapsulating resin exactly the same as that of the silicone chip, and because the elastic modulus of the encapsulating resin is large due to the filler device, it is difficult to make the coefficient of thermal expansion of the encapsulating resin exactly the same as that of the silicone chip. Since thermal stress occurs inside the package, it is strongly desired to further reduce the thermal stress.

Another means to reduce such thermal stress is as described in Japanese Patent Publications No. 4B-25759, No. 60-11975,
No. 60-18145, No. 61-54327, etc. or IEEE Transactions on Components, Hyprits, and Manufacturing Technology (IEEE Transactions on Components, Hypritz, and Manufacturing Technology)
ns On components, Hybrid
s.

ant Manufacturing Technology
gy) CHMT Volume-8, No. 4, '114486
~489 pages (1985) and 6th Annual 10
Seeding Opji International Electronics Packaging Conference (6th
AnnualProceeding of the I
international ElectronicsPa
ckaging Conference) gf,
294 = p. 512 (1986), etc., the paste resin is blended with the silicone rubber or polybutadiene rubber component in the sealing resin to form a so-called sea-island structure in the paste resin and reduce the elastic modulus of the cured product. There is a way.

[Problem that the invention seeks to solve]

However, this method aims to reduce thermal stress by reducing the elastic modulus of the sealing resin while leaving the differences in thermal expansion coefficients between the materials that make up the semiconductor device unchanged. Although it is effective for semiconductor devices with small chip sizes and semiconductor devices where the resin layer of the package is floating, it is not very effective for semiconductor devices with large chip sizes or semiconductor devices where the resin layer of the package is extremely thin. Therefore, in such a semiconductor device, a sealing resin having a small coefficient of thermal expansion and a small modulus of elasticity has been desired.

In view of this situation, the present invention aims to provide a sealing resin composition having a small coefficient of thermal expansion and a small modulus of elasticity, and a semiconductor device using the resin composition. It's about doing.

[Problem t-Means for solving]

To summarize the present invention, the first aspect of the present invention is F! A is an invention related to a resin composition, in which an inorganic filler is blended into an epoxy resin, and then, in the resin composition, a silane coupling agent, a titanate coupling agent, or an aluminum chelate cup is added to the surface of the filler. A first coating layer made of at least one coupling agent selected from the group consisting of a ring agent and a zircoaluminate coupling agent; It is characterized by being an inorganic filler formed of.

The invention @2 of the present invention relates to a resin-sealed semiconductor device, and is characterized in that a semiconductor is sealed with the resin composition of the first invention.

The above problem can be solved if the elastic modulus of the sealing resin can be prevented from increasing even if the amount of inorganic filler added is increased.

Therefore, the present inventors have investigated the surface treatment method of fillers, the relationship between the blending amount of these fillers and various physical properties of the resin m-parallel, and further investigated the development of resin-encapsulated semiconductors using these resin compositions. We conducted a series of discussions regarding the relationship between the two.

As a result, when an inorganic filler treated with a surface t-coupling agent and a second treated layer made of an elastomer with a lower elastic modulus than the epoxy resin is added to the encapsulating resin, it is possible to The increase in elastic modulus of the molded product can be considerably reduced compared to when a filler is added, and by optimizing the shape, particle size, and particle size distribution of the filler, the viscosity of the resin increases even when the amount of filler is increased. We found that it is possible to suppress the low liquidity to 7 range. By incorporating a large amount of such filler, both the coefficient of linear expansion and the modulus of elasticity of the sealing resin can be reduced.Ninthly, the thermal stress generated in the sealed product is significantly reduced, making it possible to reduce the thermal stress generated in the sealed product. Tanieno Shintoni, a stop-type semiconductor device! It has become clear that lI: can be improved.

The reason why the elastic modulus of a molded product increases when an inorganic filler is blended with an epoxy resin is that the elastic modulus of the inorganic filler is significantly higher than that of the epoxy resin, and the coating of the filler is The modulus of elasticity of the molded product can be significantly reduced compared to when a coating agent is used to coat a nydistomer, which has a low modulus of elasticity.

In the present invention, the surface of the filler? I- The purpose of coating with a coupling agent in advance is to ensure strong chemical bonding between the filler and the elastomer.

As the coupling agent used for this purpose, well-known silane-based, titanate-based, aluminum chelate-based, or zircoaluminate-based coupling agents can be used. Specifically, vinylt IJ ethoxysilane, vinyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxyglobyltrimethoxysilane, β-(3,4-epoxycyclohexyl]ethyltrimethoxysilane, r-glycidoxyglobiltrimethoxysilane, r-mercaptoglobiltrimethoxysilane, r-aminopropyltriethoxysilane, N
-(β-niaminoethyl)-r-aminopropyltrimethoxysilane, γ-ureidoglobil triethoxysilane, inglobil tridodecylbenzenesulfonyl tetanoate, tetra-inglobil bis(dioctyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) phyto) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, aluminum trisacetylacetonate, aluminum isopropylate, mono-5ec
-butoxyaluminum diisopropylate, aluminum 5ec-butyrate, ethyl acetoacetate aluminum diisopropylate, aluminum tris(
ethyl acetoacetate) and zircoaluminate compounds in which organic functional groups such as amino groups, carboxyl groups, and methacryloxy groups are bonded to the zircoaluminate skeleton.

In addition, an elastomer with a lower elastic modulus than an epoxy resin as used in the present invention means a polyalkylene, polyalkyl ether, polydimethylsiloxane, or polymethylphenylsiloxane skeleton +x in the molecule; Chemical reactivity with coupling agents and epoxy resins such as groups, amino groups, carboxyl groups, or vinyl groups?
! It is a compound with various organic functional groups.

Examples of inorganic fillers include fused silica, crystalline silica, alumina, aluminum hydroxide, zirconium silicate, mica, talc, clay, calcium carbonate, calcium silicate, and hydrated magnesium, but sealing resins In order to significantly reduce the coefficient of linear expansion of the filler, it is desirable to use bath-fused silica whose filler itself has a small coefficient of thermal expansion. Furthermore, the shape, particle size, and particle size distribution of the filler affect the melt viscosity and fluidity of the sealing resin containing the filler, and spherical shapes are more likely to increase melt viscosity and fluidity than square shapes. Since the drop is small, it is desirable to use a spherical filler when a large amount of the filler is blended. In addition, the particle size of the filler is 95% by weight or more (from L5 to 100 μm).
It is desirable that it be within the range of . This is because the melt viscosity of the sealing resin increases significantly when the filler mixture t' increases when the filler with a diameter of less than α5μm increases, and
This is because if the amount of larger filler increases, molding defects such as deformation and cutting of the bonding wires will occur when sealing the semiconductor element. In order to minimize the increase in melt viscosity and decrease in fluidity of the sealing resin when a large amount of filler is blended, it is necessary to increase the maximum optical density of the optical filler used as much as possible. Therefore, it is necessary to make the particle size distribution of the filler as wide as possible. For this purpose, when the particle size distribution of the filler is expressed by the particle size distribution formula of Rosin-Rammler (Roθin - Ramm/1θr), the slope (n) indicating the spread of the particle size distribution 9 must be [
It is desirable to exhibit linearity in the range of L5 to 1.5.

Here, the lower limit of the slope (n) is set to 05' because this is the minimum value obtained when the particle size of the filler is set in the range α5 to 100 μm. On the other hand, setting (n) smaller than 1.5 is because when (n) is larger than 1.5, the particle size distribution of the filler becomes extremely narrow9, that is, the maximum light transmittance becomes small, and the filling This occurs because the melt viscosity of the sealing resin containing the agent increases and the fluidity decreases.

Next, the epoxy resins used in the present invention include epoxy resin compositions widely used in molding materials for sealing half-body bodies, bisphenol A epoxy resin, phenol novolak epoxy resin, and 〇-Taresol. This is a composition in which novolak-type epoxy resin 11'rI* is blended with phenol novolac resin, acid anhydride, polyamine as a curing agent, and imidazole-amine, organophosphine/etc. as a curing accelerator, and these compositions require the following: Flexibility agents, coupling agents, coloring agents, flame retardants, mold release agents, etc. are added according to the requirements.

The method for producing the filler whose surface is treated with a coupling agent or an elastomer used in the present invention is not particularly limited, but can be obtained, for example, as follows. In other words, prepare a solution in which the coupling agent and elastomer are dissolved in water or various organic solvents, and use this solution as a filler.
Alternatively, the solvent may be removed by immersing the filler in this bath liquid and drying under reduced pressure, or by dry spraying. The thickness of the coating layer can be adjusted by changing the concentration of the solution and the mixing ratio of the filler and the solution.

The sealing material of the present invention can be produced in exactly the same manner as conventional sealing molding materials, and the sealing operation can be performed in the same manner.

That is, each material can be kneaded with a twin-screw roll or extruder heated to 70 to 100°C in advance, and
Mold temperature 160-200℃ using transfer press
9f/cy for molding pressure 30-100'? , curing time 1
Molding can be performed in ~3 min.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 r-amino 10-pyltriethoxysilane was dissolved in 600 tons of tetrahydrofuran and had a maximum particle size of 44 mm.
680f of spherical fused silica having an average particle diameter of 12 μm or less and a slope (n) of Rosin-Rammler particle size distribution equation of 1.0 was added to the mixture.

After standing at 60°C for 1 hour, the mixture was t-filtered,
The remaining filler in the funnel was washed with 1200 g of tetrahydrofuran. Thereafter, this mixture was transferred to a '*t-gold x mourning vat, air-dried for one day and night, and then heated in a constant temperature bath at 150°C for 3 hours to obtain a filler with a coupling agent layer formed on the surface.Next, the side chain Polydimethylsiloxane of 1ffJ50,000 10ft-tetrahydrofuran 5 having an epoxy group in
After that, tetrahydrofuran was removed using a vacuum dryer and polydimethylsiloxane NIIt- A filler having the following properties was obtained.

Example 2 6f of r-glycidoxyglobyltrimethoxysilane was dissolved in 600t of tetrahydrofuran, and 680ft of the same type of filler as that used in Example 1 above was added thereto.
- In addition, a coupling agent layer was formed on the surface of the filler in the same manner.Next, polydimethylsiloxane TOY's Tetrahydrofuran 500 with a molecular weight of 150,000 and having amino groups at both ends was added.
Example 3: A filler having a polydimethylsiloxane layer on the surface was prepared by dissolving 10 g of tetrane propyl bis(dioctyl phosphite) titanate in toluene and 6 ootrc in the same manner as above. 'ttx,
Into this was mixed 680 ft of spherical fused silica of the same type as that used in Example 1, and the mixture was left at 80°C for 1 hour. After t-filtering the mixture, the filler remaining on the funnel was washed three times with 120Of toluene, and then the remaining toluene was removed using a vacuum dryer and finally heated to 150°C.

Next, '/C
A solution prepared by dissolving 1 dFf and 10 F in 500 f of tetrahydrofuran was mixed with the above photoresist and left at 60° C. for 1 hour. Thereafter, tetrahydrofuran was removed using a vacuum dryer to obtain a filling 41' with a polydimethylsiloxane layer formed on the surface.

Example 4 Mono-5ec-ptoxyaluminum diinglovirate 5f'i dissolved in inglobil alcohol 5hof,
To this, 680 tons of the filler used in Example 1 and four-dimensional filler were added and heated at 80°C for 1 hour.Then, this mixture was filtered, and 11,200 tons of filler remained on the funnel.
After washing with isopropyl alcohol, the remaining isopropyl alcohol was removed using a vacuum dryer, and the filler was finally heated to 150°C.

Next, 1,4-polybutadiene l0 of 4000 molecular placement pieces
IF was dissolved in 500g of toluene, the above photonic agent was added thereto, heated at 80°C for 3 hours, the toluene was removed using a vacuum dryer, and finally heated to 150°C to coat the surface with 1, A filler having a 4-polybutadiene layer formed thereon was obtained.90 Example 5 Zircoaluminate 52 having a carboxyl group as a functional group was dissolved in 500 fK of in-10-byl alcohol, and during the sale, it was mixed with the filler used in Example 1. 680f of the same type of filler was added and heated at 80°C for 3 hours. This mixture was then filtered and the remaining on the funnel was
The filler was washed with 0Of isopropyl alcohol, and the remaining isopropyl alcohol was removed using a vacuum dryer, and finally the filler was heated to 150°C.

Next, acrylonitrile-modified-1,4-polybutadiene (acrylonitrile modification rate 10%, molecular weight approximately 50,000) 1
0 f t-torr x7500 tf/C dissolved,
The above-mentioned photonic agent was added to the mixture and the whole was heated at 85° C. for 1 hour. Thereafter, the toluene was removed in a vacuum dryer to obtain a filler having acrylonitrile-modified 1,4-polybutadiene mt-on the surface.

Using the thus obtained Kutani filler, a molding material having the composition shown in Table 1 below was produced using a twin-screw roll.Comparative 9111-5 Using the same method, molding materials having the compositions shown in Table 1 were prepared using the integral blending method, and each molding material exploded in this way was used to produce φl Ox.
A 100-inch round bar is molded using a transfer press, and 18
&AsTM-C696 with post-curing at 0°C/6 hours
-Linear expansion coefficient and glass transition according to 44! Measure t - then 0 ma, form a square bar of IL7 x 127 x 5, A
A bending test was conducted in accordance with 8TM-D790-66, and the strength, elastic modulus, and strain at room temperature were determined. 300
sealed in m1dDIP and subjected to thermal cycle test (-55℃
750 m1n-150℃730Win package crack resistance and sealing product 1 was immersed in a 260℃ solder bath for 30 seconds and then subjected to PCT at 121℃ and 2 atm [Pressure Cook test
erTe5t)) to determine the time to occurrence of corrosion failure (time to reach 50% failure) of aluminum wiring in the following cases.These results are summarized in Table 2.

Table 2 shows that the elastic modulus of the molded product of the uninvented resin composition is lower than that of the comparative example, and that the sealed product using this set of G's has excellent crack resistance of the package during the cold/hot cycle test lIR.
In addition, corrosion defects of aluminum wiring during moisture resistance tests are less likely to occur, and reliability is good.0 [Effects of the Invention] When the resin composition of the present invention is used, both the coefficient of linear expansion and the modulus of elasticity of molded products can be reduced. Thermal stress generated in the sealed product is then significantly reduced.

Thereby, the resin-sealed semiconductor device has excellent crack resistance and moisture resistance, and various reliability can be improved.

Patent applicant: Hitachi, Ltd. For Hitachi Chemical Co., Ltd.

Claims (1)

[Claims] 1. In a resin composition in which an inorganic filler is blended with an epoxy resin, the filler has a silane coupling agent, a titanate coupling agent, an aluminum chelate coupling agent, and a zircoaluminum coupling agent on the surface. The inorganic filler has a first coating layer made of at least one coupling agent selected from the group consisting of nate-based coupling agents, and a second coating layer made of an elastomer having a lower elastic modulus than that of the epoxy resin. A resin composition characterized by: 2. The resin composition according to claim 1, wherein the elastomer is an organopolysiloxane having a molecular weight of 5,000 or more. 3. The resin composition according to claim 1 or 2, wherein the elastomer is an organopolysiloxane having a molecular weight of 5,000 or more and having an amino group at the terminal or side chain. 4. The resin composition according to any one of claims 1 to 3, wherein the elastomer has a thickness of 0.01 μm or more. 5. Claim 1 in which the filler is fused silica
The resin composition according to any one of Items 1 to 4. 6. More than 95% by weight of the fused silica filler has a particle size in the range of 0.1 to 100 μm, and its particle size distribution has a gradient (
The resin composition according to any one of claims 1 to 5, which exhibits linearity in the range of n) from 0.5 to 1.5. 7. Any one of claims 1 to 6, wherein the epoxy resin is an o-cresol novolac type epoxy resin using a phenol novolac resin as a curing agent.
The resin composition described in . 8. A first coating layer comprising at least one coupling agent selected from the group consisting of a silane coupling agent, a titanate coupling agent, an aluminum chelate coupling agent, and a zircoaluminate coupling agent on the surface. A resin encapsulation type characterized in that a semiconductor element is encapsulated with a resin composition in which an epoxy resin is mixed with an inorganic filler and a second coating layer made of an elastomer having a lower elastic modulus than that of the epoxy resin. Semiconductor equipment.