JP2001354838A - Epoxy resin composition for sealing semiconductor and semiconductor device and method for evaluation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for sealing semiconductors excellent in reliability and moldability and to provide a semiconductor device sealed with a cured product of the resin composition and having high reliability of electrical characteristics with slight occurrence of defectives such as defective leakage. SOLUTION: This epoxy resin composition for sealing the semiconductors is characterized by having >=10 GΩ.m volume resistivity measured by using the cured product having 50-200 μm thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor encapsulation which provides a cured product which is excellent in reliability and moldability, and in particular, when used for a semiconductor device for fine pitch wiring, is less likely to cause electrical characteristics defects such as leak defects. The present invention relates to an epoxy resin composition for semiconductors, a semiconductor device sealed with a cured product thereof, and a method for evaluating an epoxy resin composition for semiconductor sealing.

[0002]

2. Description of the Related Art In recent years,
2. Description of the Related Art As the number of wirings increases as semiconductor devices become more densely packed, lighter and thinner, the pitch between aluminum pattern wirings and gold wires on the chip surface is becoming finer. In particular, the pitch between the gold wires was 100 μm or more in the past, but 50 μm,
Further, it is about to become 40 μm or less.

When such a fine-pitch wiring device is molded with a sealing material, a gold wire is damaged when the sealing material flows, and moldability defects such as gold wire flow, gold wire deformation and disconnection often occur. I do.

[0004] Therefore, in a fine pitch wiring device, it is desired to develop a semiconductor encapsulating composition and a semiconductor device which prevent the flow of gold wires and breakage of gold wires at the time of molding, and which cause less occurrence of leakage failure between the gold wires. ing.

The present invention has been made in view of the above circumstances, and has excellent reliability and moldability. Particularly, when used as a semiconductor device for fine-pitch wiring, a cured product with less occurrence of electrical property defects such as leak defects is provided. It is an object of the present invention to provide an epoxy resin composition for semiconductor encapsulation, a semiconductor device sealed with a cured product thereof, and a method for evaluating the epoxy resin composition for semiconductor encapsulation.

[0006]

Means for Solving the Problems and Embodiments of the Invention The present inventors have made intensive studies to achieve the above object, and as a result, have found that an epoxy resin composition for encapsulating a semiconductor, particularly a semiconductor containing carbon black, has been developed. By using an epoxy resin composition for semiconductor encapsulation having a volume resistivity of 10 GΩ · m or more measured using a cured product having a thickness of 50 to 200 μm as the epoxy resin composition for encapsulation, the composition is sealed with the composition. It has been found that electrical characteristics failures such as leak failures of semiconductor devices with stopped fine pitch wiring are reduced.

That is, carbon black is an essential component of a resin composition for semiconductor encapsulation as a colorant. Normally, the primary particles of carbon black are very fine, less than submicron, but coarse particles called grids of 45 μm or more,
Coarse particles such as secondary aggregates of 5 μm or more are included. It has been found that when these coarse particles of carbon black remain between the gold wires, characteristic defects such as leak failure occur between the gold wires because the carbon black is conductive.

On the other hand, a cured product sample for measuring an epoxy resin composition for semiconductor encapsulation usually has a thickness of 2 to 3 mm. In the conventional thick package,
From the volume resistivity obtained with this thickness, the reliability of the electrical characteristics of the semiconductor device could be predicted. However, as the package becomes thinner and finer, the reliability measured with this thickness becomes more difficult to predict.

The inventors of the present invention have made various studies and found that the volume resistivity measured with a cured product having a thickness of 50 to 200 μm has a correlation with characteristic defects such as leak defects of semiconductor devices, that is, reliability. By further selecting and using a cured product having a volume resistivity of 10 GΩ · m or more, an epoxy resin composition, in particular, a fine pitch wiring sealed with an epoxy resin composition containing carbon black is obtained. The present inventors have found that defective electrical characteristics such as a leak failure of a semiconductor device are reduced, and have accomplished the present invention.

Accordingly, the present invention provides an epoxy resin composition for semiconductor encapsulation, wherein the volume resistivity measured using a cured product having a thickness of 50 to 200 μm is 10 GΩ · m or more, and the epoxy resin composition. Provided is a semiconductor device sealed with a cured product.

Further, the present invention relates to an epoxy resin composition comprising
An epoxy resin composition for semiconductor encapsulation characterized by being cured to a thickness of 0 to 200 μm, measuring the volume resistivity of the cured product, and evaluating the epoxy resin composition having a value of 10 GΩ · m or more as a non-defective product. Provide an evaluation method for an object.

Hereinafter, the present invention will be described in more detail.
The epoxy resin composition for semiconductor encapsulation of the present invention usually contains carbon black and has a content of 50 to 200.
Volume resistivity measured using a cured product having a thickness of μm is 10 GΩ
M is not less than m.

The epoxy resin composition of the present invention has a composition of 50 to 2
The volume resistivity is measured on a cured product having a thickness of 00 μm, preferably 50 to 120 μm. If the thickness exceeds 200 μm, it is difficult to predict the reliability of the semiconductor device,
When the thickness is less than 50 μm, a void tends to be generated at the time of molding the cured product, and it tends to be difficult to obtain a uniform molded product due to the influence of the inorganic filler contained in the composition.

The measurement of the volume resistivity is performed according to JIS K 691.
It is measured by a method according to 1. The epoxy resin composition of the present invention has a volume resistivity of at least 10 GΩ · m, preferably at least 100 GΩ · m, as measured on the cured product having the thickness described above.

That is, as shown in FIGS.
When measuring the volume resistivity of a cured product of the epoxy resin composition for semiconductor encapsulation cured to about 200 μm, a current flows from the upper electrode 1 and the guard electrode 2 to the lower electrode 3 through the cured product 4. In this case, as shown in FIG.
When the carbon black coarse particles 5 exist in the inside, the thickness of the cured product 4 is thin, and the carbon black coarse particles 5 are conductive, so that they serve as an electric current path. Therefore, the upper electrode 1 and the guard electrode 2 A large amount of current is concentrated and flows to the lower electrode 3 through the electric path formed by the coarse particles 5. Therefore, the volume resistivity has a small value. On the other hand, even if it contains carbon black, if the coarse particles 5 do not exist, only a minute current flows uniformly as shown in FIG. 1 and the volume resistivity becomes 10 GΩ · m or more.

As described above, if the volume resistivity measured using a cured product having a thickness of 50 to 200 μm is less than 10 GΩ · m, coarse particles such as carbon black are contained. If the electrical resistivity failure such as a leak failure occurs, and if the volume resistivity is 10 GΩ · m or more, it is possible to evaluate and judge that the electrical property failure such as the leak failure is unlikely to occur between the gold wires. is there.

The epoxy resin composition of the present invention usually comprises
It contains (A) an epoxy resin, (B) a curing agent, (C) carbon black, and (D) an inorganic filler.

The molecular structure and molecular weight of the epoxy resin (A) used in the present invention are not particularly limited as long as it is a compound having at least two epoxy groups in one molecule.

As the epoxy resin, any one may be used as long as it has two or more epoxy groups in one molecule. In particular, bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin can be used. Resin, phenol novolak type epoxy resin, novolak type epoxy resin such as cresol novolak type epoxy resin, triphenol methane type epoxy resin, triphenol alkane type epoxy resin such as triphenol propane type epoxy resin, phenol aralkyl type epoxy resin, biphenyl aralkyl Type epoxy resin, stilbene type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, cyclopentadiene type epoxy resin, etc., and these may be used alone or in combination of two or more. It is possible to use Te Align.

As the curing agent (B) of the present invention, two or more functional groups (for example, phenolic hydroxyl group, amino group, acid anhydride group, etc.) capable of reacting with the epoxy group in the epoxy resin (however, acid anhydride The molecular structure, molecular weight, and the like are not particularly limited as long as the compound has one or more physical groups).

Examples of the curing agent include a phenol novolak resin, a novolak type phenol resin such as cresol novolak resin, a xylylene modified novolak resin such as a paraxylylene modified novolak resin, a metaxylylene modified novolak resin, an orthoxylylene modified novolak resin, and a bisphenol A type. Resin, bisphenol type phenol resin such as bisphenol F type resin, biphenyl type phenol resin, resol type phenol resin, phenol aralkyl type resin, biphenyl aralkyl type resin, triphenol methane type resin, triphenol alkane type such as triphenol propane type resin Examples include phenolic resins such as resins and polymers thereof, phenolic resins containing a naphthalene ring, and phenolic resins modified with dicyclopentadiene. Lumpur resin can also be used. In addition, acid anhydrides such as methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhymic anhydride, amine-based curing agents, and the like can be used. Resins are preferred because of their excellent reliability. These curing agents can be used alone or in combination of two or more.

The compounding amount of the curing agent is not particularly limited, and is an effective curing amount of the epoxy resin. For example, in the case of a phenol resin, (B) curing amount per 1 mol of epoxy group contained in the epoxy resin Phenolic OH contained in the agent
Preferably, the molar ratio of the groups is between 0.5 and 1.5.

The carbon black as the component (C) is blended for purposes such as coloring. The carbon black is not particularly limited, but for example, acetylene black, furnace black, Ketjen black, channel black, lamp black and the like can be used, and these can be used alone or in combination of two or more. can do.

When carbon black is used as a coloring agent, the particle size of the carbon black is one factor that affects the volume resistivity of the epoxy resin composition. 45μ
m or more, the volume resistivity decreases.
The particle content of 50 μm or less, especially 30 pp
m or less. Further, the content of particles having a particle size of 149 μm or more is preferably 10 ppm or less, particularly preferably 5 ppm or less.

In addition, the particle diameter is 45 μm or more and 149 μm
The above particle content is measured by the method described in JIS K6211. An example of a sieve used is 45
μm interval, wire inner diameter 200 μm, and the like.

The average particle size of carbon black (average particle size including aggregated secondary particles) is 0.1 to 35 μm.
m, particularly preferably about 1 to 30 μm.

In the present invention, the average particle diameter can be obtained as a weight average value (or median diameter) by a particle size distribution meter using an analysis means such as an analysis method such as a laser light diffraction method.

When carbon black is used as a coloring agent, the amount of addition is 0.01 to 5 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the total of (A) the epoxy resin and (B) the curing agent. ~ 3 parts by weight are preferred. The amount added is 0.01
If the amount is less than 5 parts by weight, the color tone of the cured product is less likely to be black, and if it is more than 5 parts by weight, the fluidity during molding may be reduced.

Note that an organic dye may be used as a coloring agent. As the organic dye, an azo compound, a diazo compound, a metal-containing dye and the like are used. The organic dye has little effect on the volume resistivity of the epoxy resin composition.

The inorganic filler (D) used in the present invention is other than the above-mentioned carbon black, and includes amorphous silica such as crystalline silica, spherical or crushed fused silica, alumina, silicon nitride and the like. Is used,
Spherical or crushed amorphous silica is preferred from the viewpoint of low linear expansion coefficient and high fluidity. In this case, the average particle diameter of the inorganic filler of the component (D) is usually 0.1 to 75 μm, preferably 0.5 to 35 μm, more preferably 1 to 20 μm.
m is desirable.

In order to reduce damage to a gold wire of a semiconductor device during molding, an inorganic filler having a small amount of coarse particles, particularly silica, is preferable. In a fine pitch semiconductor device, the content of particles having a particle diameter of 45 μm or more is preferred. It is recommended to use those having a value of 2.0% by weight or less, preferably 1.0% by weight or less, more preferably 0.5% by weight or less. 2.0% by weight of particles having a particle diameter of 45 μm or more
If the number is larger, the gold wire is damaged when the semiconductor device is formed, and defects such as the flow of the gold wire and the disconnection of the gold wire are likely to occur. Further, when a thin package such as TSOP, TQFP, or CSP is formed, poor penetration into a narrow portion is caused, and poor moldability such as unfilling or voids is likely to occur. In addition, as a method of measuring the content of particles having a particle diameter of 45 μm or more, a wet sieving method or the like is used.

The compounding amount of the inorganic filler of the component (D) of the present invention is as follows: the total amount of the epoxy resin (A) and the curing agent (B) is 1
The amount is desirably 250 to 1000 parts by weight, preferably 350 to 900 parts by weight, based on 00 parts by weight. 250
When the amount is less than part by weight, the coefficient of linear expansion increases, and the water absorption of the cured product of the composition increases. Also, 10
If the amount exceeds 00 parts by weight, the fluidity of the composition may be reduced, and molding may be difficult.

In the present invention, it is preferable that the inorganic filler is previously surface-treated with a coupling agent such as a silane coupling agent or a titanate coupling agent in order to further improve low water absorption, impact resistance and crack resistance. .

Examples of the coupling agent include epoxy functional groups such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Group-containing alkoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, γ
-Aminopropyltriethoxysilane, N-phenyl-
It is preferable to use a silane coupling agent such as an alkoxysilane having an amino functional group such as γ-aminopropyltrimethoxysilane, or an alkoxysilane having a mercapto functional group such as γ-mercaptopropyltrimethoxysilane. Here, the amount of the coupling agent used for the surface treatment and the surface treatment method are not particularly limited.

In the present invention, a curing catalyst is preferably used in order to accelerate the curing reaction between (A) the epoxy resin and (B) the curing agent. The curing catalyst is not particularly limited as long as it promotes the curing reaction, and those commonly used can be used, for example, triphenylphosphine,
Organic phosphorus compounds such as tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, triphenylphosphine / triphenylborane, tetraphenylphosphonium / tetraphenylborate, triethylamine, benzyldimethylamine, α-methyl Tertiary amine compounds such as benzyldimethylamine and 1,8-diazabicyclo [5.4.0] undecene-7; imidazole compounds such as 2-methylimidazole, 2-phenylimidazole and 2-phenyl-4-methylimidazole; Can be used.

The epoxy resin composition for semiconductor encapsulation of the present invention may contain an epoxy resin, a curing agent, carbon black, and an inorganic filler.
Waxes, silane coupling agents, ion trapping agents, low stress agents such as silicone polymers and thermoplastic resins, surfactants, and flame retardants such as brominated epoxy resins and antimony compounds impair the purpose of the present invention. It can be added and compounded within a range not to be included.

A general method for preparing the epoxy resin composition for semiconductor encapsulation of the present invention as a molding material is as follows: an epoxy resin, a curing agent, carbon black, an inorganic filler, and other additives are added to a predetermined composition. After mixing the mixture in a uniform ratio using a mixer or the like, the mixture is melt-mixed using a hot roll or a kneader, then solidified by cooling, and pulverized to an appropriate size to obtain a molding material.

The molding material thus obtained can be used for sealing and coating electronic parts or electric parts including semiconductor devices, and by using this molding material, excellent properties and reliability can be imparted. Can be done.

The semiconductor device of the present invention can be easily manufactured by sealing a semiconductor element using the above-described epoxy resin composition for semiconductor sealing. The semiconductor element for sealing is not particularly limited,
For example, there are an integrated circuit, a transistor, a thyristor, a diode, and the like. Particularly, when used for a fine pitch wiring device, excellent characteristics are exhibited.

The most common method of sealing a semiconductor device is a transfer molding method. Further, it is preferable that the epoxy resin composition for semiconductor encapsulation is further heated and post-cured after molding.
It is desirable to carry out the heating under 0 ° C. or more.

[0041]

The epoxy resin composition for semiconductor encapsulation of the present invention has excellent reliability and moldability, and a semiconductor device encapsulated with a cured product of the resin composition has few defects such as leak defects. High reliability of electrical characteristics.

[0042]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples 1 to 4, Comparative Examples 1 to 3] Using the coloring agents shown in Table 1, the components shown in Table 2 were uniformly melted and mixed with two hot rolls, cooled and pulverized to obtain semiconductors. A sealing resin composition was obtained.

With respect to these compositions, the following (a) to (b)
Various tests of (d) were performed. The results are also shown in Table 2. (A) Spiral flow value Using a mold conforming to the EMMI standard, 175 ° C, 70
It was measured under the condition of kgf / cm ² . (B) Volume resistivity (1) 100 at 175 ° C., 6.9 N / mm ² , 120 seconds
A molded product having a size of 100 mm x 100 mm was obtained. Using the obtained cured product, the volume resistivity was measured under the following conditions in accordance with JIS K 6911.

Main electrode = 50 mmφ Guard electrode =
Inner diameter 70mmφ, outer diameter 80mmφ Electrode material = conductive paste Applied voltage = DC 500V Measurement time = 1 minute after application Measuring instrument = Ultra-insulation resistance meter (c) Volume resistivity (2) (b) Size 100mmφ × 2m
m, 100mmφ × 1mm, 100mmφ × 0.5mm
Other than the above, the volume resistivity was measured in the same manner as in (b). (D) Leakage defect Using a flat package of 20 mm × 20 mm × 1.0 mm on which a chip having a size of 6 mm × 6 mm × 0.35 mm is mounted, a gold wire interval of 70 μm, a gold wire diameter of 25 μm,
A device wired with a gold wire length of 5 mm was heated at 175 ° C, 70
The molding was performed under the molding conditions of kgf / cm ² and 120 seconds. After the molded device was post-cured at 180 ° C. for 4 hours, the device was left in a thermo-hygrostat at 85 ° C./85% RH for 72 hours to absorb moisture, and the current value flowing between the gold wires was measured.
Those having a current value of 10 μA or more were regarded as defective.

[0046]

[Table 1] Organic dye: oil black CB-10 (manufactured by Mihara Chemical)

[0047]

[Table 2] Biphenyl type epoxy resin: YX-400 made by Yuka Shell
0HK (epoxy equivalent 190) Curing agent: phenol aralkyl resin, Mitsui Toatsu XL-
225-3L (phenol equivalent: 168) Silane coupling agent: γ-glycidoxypropyltrimethoxysilane, KBM-403 silica manufactured by Shin-Etsu Chemical: average particle diameter: 10 μm, specific surface area: 0.8 m ²
/ G, coarse fraction of 45 μm or more; 0.4% by weight of spherical silica

From the results shown in Table 2, there is a good correlation between the volume resistivity measured with the cured product having a thickness of 0.1 mm and the leak failure. Moreover, it was demonstrated that the resin composition for semiconductor encapsulation of the present invention has few electric property defects.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a method for measuring volume resistivity in one embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a method for measuring volume resistivity in a comparative example of the present invention.

[Explanation of symbols]

 Reference Signs List 1 upper electrode 2 guard electrode 3 lower electrode 4 cured product 5 coarse particles

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shiba ▲ Saki ▼ Yoshimitsu 2-13-1 Isobe, Annaka-shi, Gunma Shin-Etsu Chemical Co., Ltd. Gunma Office (72) Inventor Toshio Shiobara Matsui, Usui-gun, Gunma Hitomi Tamachi 1-10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory F-term (reference) 4J002 CC032 CC042 CC052 CC072 CD021 CD031 CD041 CD051 CD061 DA037 DE148 DJ008 DJ018 EL136 EN006 FA088 FB138 FB148 FB158 FB168 FD018 FD090 FD0 GJ02 GQ05 4M109 AA01 CA21 EA02 EB02 EB08 EB12 EC07

Claims (5)

[Claims] 1. An epoxy resin composition for semiconductor encapsulation having a volume resistivity of at least 10 GΩ · m measured using a cured product having a thickness of 50 to 200 μm. 2. An epoxy resin composition comprising: an epoxy resin;
2. The epoxy resin composition for semiconductor encapsulation according to claim 1, comprising a curing agent, carbon black, and an inorganic filler other than carbon black. 3. A semiconductor device encapsulated with a cured product of the epoxy resin composition for semiconductor encapsulation according to claim 1 or 2. 4. An epoxy resin composition having a thickness of 50 to 200 μm.
Evaluation of the epoxy resin composition for semiconductor encapsulation, wherein the epoxy resin composition having a thickness of 10 GΩ · m or more is measured as a non-defective product by measuring the volume resistivity of the cured product. Method. 5. An epoxy resin composition comprising: an epoxy resin;
The evaluation method according to claim 4, further comprising a curing agent, carbon black, and an inorganic filler other than carbon black.