JP3143219B2 - Spherical filler and resin composition for semiconductor encapsulation using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filler and a resin composition for encapsulating a semiconductor using the same, especially a large scale integrated circuit (LS).
I) A resin composition suitable for sealing an element.

[0002]

2. Description of the Related Art Conventionally, an LSI element has a large number of fine transistors and wiring patterns formed on a silicon substrate, and is extremely sensitive to mechanical, thermal, electric shocks and atmospheric changes. There is a disadvantage that it is easily damaged. In order to solve this, an element is sealed with a sealing material made of a resin composition containing a resin such as an epoxy resin and a filler such as fused silica.

[0003]

In recent years, the degree of integration of LSI elements has been further improved, and due to the miniaturization of wiring patterns and the increase in the area per element, etc., elements have become mechanically, thermally, It is more sensitive and more susceptible to electrical or chemical stimuli than before. Therefore, research on the improvement of resins and fillers to be used is being actively conducted. For example, regarding fillers, high thermal conductivity such as silicon nitride, aluminum nitride, aluminum oxide, etc., instead of or together with fused silica, is used. Use of ceramics has been studied (Japanese Patent Application Laid-Open No. 61-91243).

[0004] However, since the thermal expansion of high thermal conductive ceramics is about one order of magnitude higher than that of fused silica, the thermal expansion coefficient of the encapsulant using it is higher than that of the element, and thermal stress is generated. In addition, cracks are generated in the sealing material, and in extreme cases, the element is broken, and the improvement is not as expected.

[0005] In addition, high thermal conductive ceramics generally have an irregular shape. Therefore, when the filling rate of the resin is increased, the fluidity of the resin composition is reduced and the moldability is deteriorated. Further, the high thermal conductive ceramics have high mechanical strength, so that the mold wears quickly and the mold life is shortened.

[0006] In order to prevent the deterioration of the moldability and the shortening of the mold life as described above, the use of spherical particles of high thermal conductive ceramics has been tried, but there is no effect of reducing the thermal stress.
In addition, there is a problem that the manufacturing cost is significantly increased because the manufacturing process is complicated or expensive raw materials are required.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above problems, and the gist of the invention is that the chemical composition is represented by a composition formula of SiO _{2 (1-x)} N _{(4/3) x} (where, 0.003 ≦ x ≦ 0.3
8 ) A filler characterized by containing spherical nitrogen-containing silica glass particles represented by the following formula as main components, an epoxy resin, a curing agent for epoxy resin, and a semiconductor characterized by containing the filler. Resin composition for sealing, especially LS
It is a resin composition suitable for sealing an I element.

Hereinafter, the present invention will be described in more detail.

[0009] The nitrogen-containing silica according to the present invention must be glassy, and if it is crystalline, the thermal expansion coefficient increases and a large thermal stress is generated in the sealing material. Here, "vitreous" means that no diffraction line is observed by X-ray diffraction analysis.

The chemical composition of the nitrogen-containing silica glass according to the present invention is represented by a composition formula: SiO _{2 (1-x)} N _{(4/3) x} (where 0.00
3 ≦ x ≦ 0.38 ). Where x <0.00
In No. 3, there is no effect of improving the thermal conductivity, and x> 0.38
In this case, crystalline silicon oxynitride (Si ₂ ON ₂ ) or silicon nitride is contained, and a significant thermal stress suppressing effect is lost.

The maximum particle size of the filler containing the spherical nitrogen-containing silica glass particles of the present invention as a main component is 1 mm.
It is preferably 0.1 mm or less. In particular, in the case of a filler for a resin composition for semiconductor encapsulation, the smaller the particle size, the less damage or damage to the wiring, passivation film, bonding wire, etc. on the element surface during molding is reduced. Although the maximum particle size is 500 μm in consideration of gate clogging during transfer molding,
It is preferably 149 μm or less, particularly preferably 74 μm or less.

In the present invention, the term "spherical" refers to a particle having a ratio of (minor axis) / (major axis) of 0.8 or more in a projected view of a particle.

The filler of the present invention is, for example, the following (i)
It can be produced by the method (iii). (I) Nitrogen-containing silica glass is produced by heat-treating active silicon oxide such as porous silicon oxide in an ammonia atmosphere at 500 to 1500 ° C., pulverizing the glass, adjusting the particle size, and treating with a flame. Method.

(Ii) A flame is generated by a combustible gas containing an oxygen gas and a combustible gas containing a nitrogen atom such as ammonia, and a silicon oxide powder is supplied into the flame for heating and melting. A method of reacting with nitrogen.

(Iii) A flame is generated by a combustible gas containing nitrogen atoms such as ammonia and a supporting gas containing oxygen gas, and a silicon powder is supplied into the flame for heating and melting, And reacting with nitrogen.

The content of the filler of the present invention in the resin composition varies depending on the type and application of the resin. In the case of a resin composition for encapsulating a semiconductor, the content is 20 to 97% by volume, preferably 4 to 97% by volume.
0 to 90% by volume. When the content of the filler is less than 20% by volume, the moldability of the resin composition is excellent, but the thermal stress increases, and the heat shock resistance and the humidity resistance decrease. on the other hand,
If it exceeds 97% by volume, the moldability of the resin composition is impaired,
Unfilled portions and voids are generated, and electrical insulation and reliability are impaired.

As the resin in which the filler of the present invention is used, bisphenol type epoxy resin, phenol novolak type epoxy resin, alicyclic type epoxy resin, heterocyclic type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin Epoxy resins such as halogenated epoxy resins, polybenzimidazole, polybenzoxazole, polybenzthiazole, polyoxadiazole, polypyrazole, polyquinoxaline, polyquinazolinedione, polybenzoxazinone, polyindrone, polyquinazolone, polyindoxyl, Silicon resin, silicon-epoxy resin, phenol resin, melamine resin, urea resin, unsaturated polyester, polyaminobismaleimide, diallyl phthalate resin, fluororesin, TPX resin (methyl Penten polymer (trade name of Mitsui Petrochemical Co., Ltd.), polyimide, polyamide imide, polyether imide, 66-nylon, MXD-nylon, polyamide such as amorphous nylon, polyester such as polybutylene terephthalate and polyethylene terephthalate, polyphenylene sulfide, modified Polyphenylene ether, polyarylate, wholly aromatic polyester,
Polysulfone, liquid crystal polymer, polyetheretherketone, polyethersulfone, polycarbonate, maleimide-modified resin, ABS resin, AAS (acrylonitrile
Acrylic rubber / styrene resin and AES (acrylonitrile-ethylene-propylene-diene rubber-styrene) resin.

Of these, epoxy resin is preferable as the resin of the resin composition for encapsulating a semiconductor, and kerimide (Mitsui Mitsui) is used in order to improve the bonding strength with metals and the bending strength at higher temperatures. Polyaminobismaleimide-based resins such as Petrochemical Co., Ltd.) and BT resin (Mitsubishi Gas Chemical Co., Ltd.) are preferred.

Examples of the curing agent for the epoxy resin include phenolic curing agents such as phenol novolak and cresol novolak, and acid anhydride curing agents such as tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride. I can give it. The amount used is preferably 30 to 90 parts by weight based on 100 parts by weight of the epoxy resin.

The resin composition using the filler of the present invention may further contain rubber components such as butyl rubber, acrylic rubber, ethylene propylene rubber, silicone rubber, polyester elastomer, and polybutadiene in order to enhance thermal shock resistance. Can be.

Further, if necessary, the following curing accelerators, catalysts, vulcanizing agents, lubricants / release agents, stabilizers, light stabilizers,
A coloring agent, a flame retardant, a coupling agent, and the like can be added.

Benzoguanamine, as a curing accelerator,
2,4-dihydrazino-6-methylamino-S-triazine, 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-
Imidazole derivatives such as methylimidazole, various amine complexes of boron fluoride, tertiary amine compounds such as trisdimethylaminomethylphenol, 1,8-diazabicyclo (5,4,0) -undecene-7, benzyldimethylamine , Dicyandiamide, amino alcohol compounds obtained by reaction of bisphenol type epoxy resin or cresol novolak type epoxy resin with ammonia, nitrogen-containing curing accelerators such as adipic hydrazide, triphenylphosphine, tricyclohexylphosphine, methyldiphenylphosphine, tolyl Organic phosphine-based hardening accelerators such as phosphine, 1,2-bis (diphenylphosphino) ethane, and bis (diphenylphosphino) methane can be given.

Examples of the catalyst include curing catalysts such as bis- (tributyltin) oxide, tin dioctenoate, antimony octoate, tin butyrate, lead monoxide, lead sulfide and lead carbonate, and polymerization catalysts such as platinum compounds. Can be.

Examples of the vulcanizing agent include benzoyl peroxide, dicumyl peroxide and the like.

Examples of the lubricant / release agent include carnauba wax, montana wax, polyester oligomer, silicone oil, low molecular weight polyethylene, paraffin, metal salts of straight-chain fatty acids, acid amides, esters and the like.

Examples of the stabilizer include 2,6-di-tert-butyl-4-methylphenol, 1,3,5-tris (2-methyl-4-hydroxy-5-tert-butylphenol) butane, distearylthio Examples include dipropionate, trinonylphenyl phosphite, tridecyl phosphite and the like.

Light stabilizers include 2,2'-dihydroxy-4-methoxybenzophenone, 2 (2'-hydroxy-5-methylphenyl) benzotriazole,
Examples include t-butylphenyl salicylate, ethyl-2-cyano-3,3-diphenylacrylate and the like.

Examples of the coloring agent include bengara, carbon black and the like.

As the flame retardant, antimony trioxide, antimony tetroxide, triphenylstibine, hydrated alumina,
Examples include ferrocene, phosphazene, hexabromobenzene, tetrabromophthalic anhydride, tricresyl phosphate, tetrabromobisphenol A, and brominated epoxy derivatives.

For coupling, vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, N-
silane coupling agents such as β- (aminoethyl) -γ-aminopropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane,
Titanium-based coupling agents such as isopropyltriinstearoyl titanate, dicumylphenyloxyacetate titanate, bis (dioctylpyrophosphate) oxyacetate titanate, and isopropyltridecylbenzenesulfonyl titanate; and aluminum-based coupling agents such as acetoalkoxyaluminum diisopropylate Etc. can be given.

The resin composition containing the filler of the present invention comprises:
After sufficiently mixing a predetermined amount of each of the above components with a Henschel mixer or the like, a roll, a Banbury mixer, a kneader,
It can be manufactured by heating and kneading by a known kneading means such as a grinder, an azimohomomixer, a twin-screw extruder, and a single-screw extruder.

[0032]

EXAMPLES The present invention will be described more specifically with reference to Examples, Comparative Examples and Reference Examples.

Example 1 A mixture of water and ethanol was added dropwise to a commercially available tetraethoxysilane solution, and the mixture was stirred and allowed to stand at a temperature of 35 ° C. for 10 hours, and then gradually heated to a temperature of 80 ° C. over 2 days. A wet gel of silicon oxide was produced. Thereafter, the temperature is gradually raised from room temperature to a temperature of 150 ° C. in vacuum over 2 days.
It was heated, further kept at that temperature for 2 days, and dried to obtain a porous silicon oxide made of a silica gel body. It was heated to 1200 ° C. in a nitrogen atmosphere, kept at that temperature for 15 hours after introducing ammonia gas, and then cooled to room temperature under a nitrogen atmosphere.

With respect to the obtained material, silicon was analyzed by an IPC (high frequency plasma emission spectroscopy) method, and oxygen and nitrogen were analyzed by an oxygen / nitrogen simultaneous analyzer (trade name “TC-
136 "). As a result, the composition formula SiO _0.88 N _0.75 (x = 0.56) was determined. No diffraction line was observed in the X-ray diffraction analysis.

Next, the nitrogen-containing silica glass was pulverized to a maximum particle size of 74 μm and an average particle size of 20 μm, which was formed by using oxygen gas and propane gas at a temperature of 1800 ° C.
In the flame. Throughout this experimental example, a flame was formed in a chamber maintained under a nitrogen atmosphere to prevent volatilization of nitrogen from the nitrogen-containing silica glass.

When the collected matter in the lower part of the chamber that passed through the flame was observed under a microscope, it was found to be spherical particles having an average particle diameter of about 15 μm and a ratio (minor axis) / (major axis) of 0.9.
Further, when a chemical analysis was performed to determine a composition formula, it was found that
_1.23 N _0.51 (x = 0.38), and no diffraction line was observed by X-ray diffraction analysis.

Example 2 Fused silica powder having an average particle size of 10 μm was dispersed in oxygen gas, and supplied into a flame of 1900 ° C. formed by the oxygen gas and ammonia.
Spherical nitrogen-containing silica glass particles were produced in which (short diameter) / (long diameter) was 0.85, and no diffraction line was observed by X-ray diffraction analysis. The composition formula of this by chemical analysis is SiO
_1.871 N _0.084 (x = 0.063).

Example 3 In Example 2, silicon powder having an average particle size of 10 μm was supplied to the flame in place of the fused silica powder, and the average particle size was changed to 5 μm.
μm, (minor axis) / (major axis) 0.8, composition formula SiO
_1.81 N _0.13 (x = 0.094), spherical nitrogen-containing silica glass particles with no diffraction line observed by X-ray diffraction analysis were produced.

Comparative Example 1 The porous silicon oxide made of the silica gel body produced in Example 1 was heated to a temperature of 600 ° C. in a nitrogen atmosphere. Cooled to room temperature underneath. The composition formula of the obtained nitrogen-containing silica glass is SiO _1.965 N _0.021 (x
= 0.016), and no diffraction line was observed in the X-ray diffraction analysis.

Next, this was pulverized to a maximum particle size of 74 μm and an average particle size of 20 μm, and supplied into a flame of 2000 ° C. formed by oxygen gas and propane gas. Microscopic observation of the collected matter in the lower part of the chamber that passed through the flame revealed spherical particles having an average particle diameter of about 18 μm and a ratio (minor axis) / (major axis) of 0.8. The composition formula is SiO _1.996 N _0.003 (x = 0.002),
No diffraction line was observed by X-ray diffraction analysis.

Comparative Example 2 The porous silicon oxide made of the silica gel body produced in Example 1 was heated to a temperature of 1600 ° C. in a nitrogen atmosphere. Cooled to room temperature underneath. The composition formula of the obtained material is SiO _0.37 N _1.09 (x = 0.82), and in the X-ray diffraction analysis, silicon oxynitride (Si ₂ O
N ₂ ) and silicon nitride diffraction lines were observed.

Next, this was pulverized to a maximum particle diameter of 74 μm and an average particle diameter of 20 μm, and supplied into a flame of 1800 ° C. formed by oxygen gas and propane gas. Microscopic observation of the collected matter in the lower part of the chamber that passed through the flame revealed that the particles had an average particle size of about 20 μm and had irregular shapes. The composition formula is SiO _0.46 N _1.03 (x
= 0.77), and diffraction lines of silicon oxynitride (Si ₂ ON ₂ ) and silicon nitride were recognized in the X-ray diffraction analysis.

In a first example, 40 parts by weight of a phenol novolak resin was added as a curing agent to 100 parts by weight of a main agent having a weight ratio of ortho-cresol novolak type epoxy resin: brominated cresol novolak type epoxy resin of 100: 20. To 3 and Comparative Examples 1 and 2 (both having a maximum particle size of 74 μm and an average particle size of 10 μm
Was mixed so as to contain 70% by volume to produce a resin composition.

After measuring the spiral flow length of the obtained resin composition with a Koka type flow tester to evaluate the fluidity, a low-pressure transfer molding was performed to obtain a molded product, and the thermal conductivity was determined by a steady-state method. It was measured by a thermal conductivity measuring device. Table 1 shows the results.

Next, using the resin composition described above, ten molded bodies each of which was formed by sealing an aluminum lead frame and a silicon element by low-pressure transfer molding were produced.
Repeat rapid cooling and rapid heating from -200 ° C to 200 ° C,
The number of cycles in which cracks occurred in 5 or more of the 10 compacts was measured, and the thermal stress property was evaluated. Furthermore, mold wear was evaluated by measuring the surface roughness (center line average roughness) of the mold when the low-pressure transfer molding was repeated 1000 times continuously using the resin composition. Table 1 shows the results.

Reference Examples 1 to 4 As fillers, fused silica powder having an average particle diameter of about 10 μm (Reference Example 1), silicon nitride powder (Reference Example 2), silicon oxynitride (Si ₂ ON ₂ ) powder (Reference Example 3) ) And aluminum nitride powder (Reference Example 4).
Table 1 shows the results.

[0047]

[0048]

The resin composition using the filler of the present invention is
Since it has high thermal conductivity, low thermal stress, high fluidity, and low mold abrasion, the effect of reducing damage to semiconductor elements, particularly LSI elements, and the effect of increasing the life of molds are large, which greatly contributes to improvement in semiconductor productivity.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08K 3/00-13/08 C08L 1/00-101/16 H01L 23/30 CA (STN)

Claims (2)

(57) [Claims] The chemical composition is represented by a composition formula SiO _{2 (1-x)} N _{(4/3) x}
(However, a filler characterized by containing spherical nitrogen-containing silica glass particles represented by the following formula : 0.003 ≦ x ≦ 0.38 ) as a main component. 2. A resin composition for encapsulating a semiconductor, comprising an epoxy resin, a curing agent for the epoxy resin, and the filler according to claim 1.