JPH03143944A - Liquid resin composition for semiconductor - Google Patents

Abstract

PURPOSE:To suppress the corrosion of an aluminum wiring on the surface of a semiconductor element when used as a protective resin for the semiconductor element and to improve the humidity resistance by compounding a specific fluorocopolymer with aminosilane and an org. solvent. CONSTITUTION:The title liq. resin compsn. is prepd. by compounding, as the essential components, 100 pts.wt. vinylidene fluoride-hexafluoropropylene copolymer of the formula wherein m/n is 1-20; 0.3-5 pts.wt. aminosilane; and an org. solvent, pref. a ketone such as methyl ketone or methyl isobutyl ketone, a polar solvent such as dimethylformamide or N-methyl-2-pyrrolidone, or a combination of these solvents.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a resin that protects the surface of a semiconductor element, and more specifically, a resin that has very low water absorption and excellent adhesion to the surface of a semiconductor element. This invention relates to a liquid resin composition for semiconductors whose purpose is to prevent corrosion of aluminum wiring on the surface of a device caused by moisture intrusion from the outside.

[Conventional technology]

There are two main ways to encapsulate semiconductor elements with organic materials. One is to transfer mold the element bonded onto a metal lead frame using a solid resin composition, and the other is to transfer mold the element bonded onto a metal lead frame. One is a method of sealing an element bonded onto a printed wiring board or the like by a dropping method using a liquid resin and a liquid resin.

Epoxy resins are often used in all of the above applications because they have excellent adhesive properties, electrical properties, and mechanical properties. However, since epoxy resin uses a chlorine compound called epichlorohydrin as a raw material, it contains a small amount of chlorine, which poses a problem in that the resin absorbs moisture and causes corrosion of the aluminum wiring of semiconductor devices.

To prevent this, methods such as covering the element surface with a polyimide resin film in advance and then transfer-molding it with an epoxy resin composition are sometimes taken, but polyimide resin easily absorbs moisture, and even if chlorine etc. can be prevented to some extent, the element surface On the other hand, there is a disadvantage that the moisture content increases and causes corrosion of the aluminum wiring.

In addition, in order to make the liquid resin easier to use in the dropping method, a low-viscosity curing agent is often used. For example, a liquid acid anhydride such as tetrahydrophthalic anhydride is often used. In this case, the cured product contains many ester bonds that are easily hydrolyzed in the cured structure, so its moisture resistance is poor, and it is particularly difficult to handle the pressure and pressure required as a semiconductor resin.
In the Kutzker test (hereinafter referred to as PCT test), there was a problem that moisture could easily penetrate directly through the resin or through the interface between the resin and the substrate, causing corrosion of the aluminum wiring of semiconductor elements. .

[Problem to be solved by the invention]

The object of the present invention is to provide a liquid resin composition that improves the above-mentioned drawbacks as a resin for protecting semiconductor elements, and is resistant to corrosion of aluminum wiring on the surface of semiconductor elements even in PCT tests, and has excellent moisture resistance. It is in.

[Means to solve the problem]

The present invention relates to a CF for improving adhesion to a copolymer (A) of vinylidene fluoride and propylene hexafluoride represented by the specific formula CI) having a low saturated water absorption rate.

+ CHz-CF t+i-+CF CF z+-V
...(1) Aminosilane (B) and organic solvent (C)
A liquid resin composition having as an essential component, the copolymerization ratio m/n of (A) is ~20, and the blending ratio (A)/(B) of (A) and (B) is 10010. .3~1001
5 parts by weight of a liquid resin composition for semiconductors.

[For production]

A feature of the liquid resin composition of the present invention is that the water absorption rate of the cured product is extremely low.
In the test, it is easily susceptible to hydrolysis, has a high water absorption rate, and has very low moisture resistance.

In addition, even with ordinary epoxy resin transfer molding materials, the saturated water absorption rate in the PCT test is about 0.7%, which means that even if it is assumed that the inorganic filler does not absorb water at all, the epoxy resin as a binder absorbs about 2% of water. This is to do so.

The fluororesin, which is a copolymer of vinylidene fluoride and propylene 67) used in the present invention, has a very low saturated water absorption rate in the PCT test, which is 0.05% or less.

However, in the copolymer represented by formula [I], if the copolymerization ratio m/n is greater than 20, the fluorine content will be low and the water absorption will be high. Moreover, if m/n is smaller than 1, the water absorption rate will be low but the moisture permeability will be high.

In addition, fluororesins generally have strong non-adhesiveness with other substances, and cannot be used as they are because they have poor adhesion with semiconductor elements for the purpose of the present invention, and the resin itself has a low water absorption rate. However, moisture intrudes from the interface between the semiconductor element surface and the resin, causing problems such as corrosion of the aluminum wiring.

In order to improve this drawback, the inventors of the present invention have conducted extensive studies on various types of strength/sampling agents, and have found that when aminosilane is added to the fluororesin used in the present invention, adhesion is significantly improved, which was previously unimaginable. The present invention has been found to be improved and the object of the present invention has been achieved.

The aminosilane used in the present invention is a compound having both an amino group and a silanol group, or an amino group and a silanol group derivative, such as aminoethylsilanol, aminoethyltrimethoxysilane, aminoethyltriethoxysilane, aminopropylsilanol. , aminoethyltrimethoxysilane, aminopropyltriethoxysilane, γ-(2-ureidoethyl)aminopropyltrimethoxysilane, T-ureidopropyltriethoxysilane, and the like.

Regarding the amount of aminosilane to be blended, as a result of various studies, 0.3 parts by weight to 5 parts by weight of aminosilane is suitable for 100 parts by weight of the fluororesin represented by the above formula [I].

If the amount is less than 0.3 parts by weight, the effect of improving adhesion will hardly be achieved. Further, if the amount is more than 5 parts by weight, although it has some effect on adhesion, the excess aminosilane will be eluted in the PCT test, increasing the water absorption rate and causing aluminum corrosion on the surface of the semiconductor element.

Further, as the aqueous solvent used in the present invention, any solvent that can dissolve the copolymer of vinylidene fluoride and propylene hexafluoride can be used, but in particular, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone can be used. Solvents, polar solvents such as dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, or combinations thereof are excellent.

In addition, heat curing of the liquid resin composition of the present invention requires curing at low temperature when a low boiling point solvent is used, and at high temperature when using a high boiling point solvent. Multi-stage curing, e.g. 60~120°
C/60 minutes → 150-200°C/60 minutes is preferable.

In the present invention, there is no problem in adding an antifoaming agent, a dispersion stabilizer, a coloring agent, etc., if necessary.

If the liquid resin composition according to the present invention is applied to the surface of a semiconductor element, cured by heating, and then transfer molded with an epoxy resin, the moisture resistance is significantly improved compared to the case of only transfer molding.

The liquid resin of the present invention is also useful as a sealing resin for bare elements bonded directly onto a printed wiring board or the like. Tape automated bonding (TAB)
It is particularly useful as a semiconductor element protection resin.

[Example 1] CF is a copolymer of vinylidene fluoride and propylene hexafluoride represented by the following formula (r).

-(-CHz-CF #-f-CF -CF 2+T-
...(1) Above copolymerization The copolymer with $m/n=10 was dissolved in dimethylacetic acid to a concentration of 20%.

Aminosilane was blended into this solution at the blending ratio shown in Table 1, and thoroughly stirred with a three-one motor to obtain a homogeneous liquid sealing resin composition.

This resin m acid was applied onto a silicone wafer using a spinner and cured at 100°C/60 minutes → 200'C for 60 minutes under the PCT test conditions (125°C, 12,3 atm,
100% RH), and the adhesion to the silicone wafer was examined. In addition, in the same process, this resin composition was cast on an aluminized foil and cured, and then the aluminum foil was removed by etching to make a 100 μm thick film, and the water absorption rate and moisture permeability (JIS-Z-0208 ) was measured.

Furthermore, using a dispenser, this resin composition was drop-sealed onto the surface of the simulated element and cured under the above conditions.

Then, the PCT test conditions (125°C, 2.3 atm, 1
00% RH) and the time required for aluminum corrosion to occur was investigated.

The simulated element used was a chip in which aluminum was deposited in a comb-shaped pattern with a line spacing/width of 5 μm on a 5 mm square silicone wafer, and soldered onto a wiring tape (copper/polyimide film) for tape automated bonding. They are joined using bumps.

The above test results are shown in Table 1.

Examples 2 to 5, Comparative Examples 1 to 6 Liquid resin compositions were prepared in the same manner as in Example 1 using the formulations shown in Table 1, and the same tests were conducted. Table 1 shows the results.

[Effects of the Invention] The liquid resin composition for semiconductors obtained by the present invention has extremely low water absorption and excellent adhesion to silicon wafers, which is far superior to conventional semiconductor element protection resins. A cured product with high reliability in the PCT test, which could not be obtained, was obtained, and is extremely excellent for use in semiconductors.

Claims (1)

[Claims] (1) (A) Copolymer of vinylidene fluoride and propylene hexafluoride represented by the following formula [I]▲There are mathematical formulas, chemical formulas, tables, etc.▼... [I] (B) Aminosilane (C) Organic A liquid resin composition containing a solvent as an essential component, in which the copolymerization ratio m/n of (A) is 1 to 20, and the blending ratio (A)/(B) of (A) and (B) is 100/ A liquid resin composition for semiconductors, characterized in that the amount is 0.3 to 100/5 parts by weight.