JPS59122558A - Organopolysiloxane composition for coating of semiconductor element - Google Patents

Abstract

PURPOSE:To provide the titled comosition containing a specific vinyl-containing polysiloxane, a hydrogen (cyclo)polysiloxane, a platinum catalyst and less than a specific amount of uranium and thorium, and also having alpha-ray shielding property. CONSTITUTION:The objective composition is compsed mainly of (A) a diorgano- polysiloxane blocked with diorganovinylsilyl group at both terminals, (B) an organohydrogen (cyclo)polysiloxane blocked with triorganosilyl group at both terminals, and (C) a catalytic amount of platinum catalyst (preferably complex salt of platinum and vinylsiloxane). The ratio of (the equivalent number of the hydrogen atom bonded to Si atom in the component B)/(the equivalent number of the viny group bonded to Si atom in the component A) is (0.2-6)/1, and the total content of uranium and thorium in the objective composition is <=1ppb by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to organopolysiloxane compositions for coating semiconductor devices.

Conventionally, semiconductor elements have been protected from moisture and external stress, and semiconductor elements have been coated with silicone gel or rubber. Addition reaction cross-linked organopolysiloxandels are known and widely used as such silicone gels. Further, addition reaction crosslinking type organopolysiloxane rubber, condensation reaction crosslinking type or room temperature vulcanization type organopolysiloxane rubber are known and used as such silicone rubbers.

However, as the integration of semiconductor devices has progressed in recent years, alpha rays are being emitted from radioactive substances contained in the encapsulating materials used in LSIs, VLSJs, and especially VLSIs, such as ceramic encapsulating materials and resin encapsulating materials. As a result, materials for covering semiconductor devices are strongly discouraged from having the ability to block alpha rays. However, conventionally known and used silicone-based gels and rubbers for covering semiconductor devices have been problematic due to their poor α-ray shielding ability.

Therefore, the present inventors conducted intensive studies to develop a coating material for semiconductor devices that also has the function of blocking A-rays, and as a result, they arrived at the present invention.

That is, the present invention provides: 1(a) a diorganopolysiloxane endblocked with organovinylsilyl groups at both ends;

(b) Both ends end-blocked with triorganosilyl groups, 7-hydronoenebolysiloxane or organohydrothenecyclopolysiloxane, and (c) platinum-based catalyst as main ingredients; Equivalent of 1/[equivalent of silicon-bonded vinyl group in component (a)] = 0.2/1 to 6/1, and component ()1) is in a catalytic amount, and uranium and The present invention relates to an organopolysiloxane composition for coating semiconductor devices, characterized in that the total amount of thorium is 1 ppb or less by weight.

To explain this, (a) I& is the main component of the organopolysiloxane composition of the present invention, and the vinyl groups at both ends, the silicon-bonded hydrogen atoms of the (b) component, and (
=l The binding linkage is cross-linked by the addition reaction and becomes gel-like or rubber-like. Examples of the diorganovinyl groups at both ends include a dimethylvinyl group, a methylphenylvinyl group, a nophenylvinyl group, and a methylpropylvinyl group. As the main chain diorganopolysiloxane, dimethylpolysiloxane,
Methylphenylpolysiloxane.

Methyl(3,3,3-trifluoropropyl)polysiloxane, methyloctylpolysiloxane, dimethylsiloxane/methylphenylsiloxane copolymer, dimethylsiloxane Φ diphenylsiloxane copolymer, trimethylsiloxane/methyl(3,3,3) -trifluoropropyl) siloxane copolymer is exemplified. Among these diorganopolysiloxanes, dimethylsiloxane/methylphenylsiloxane copolymers, especially those having a molar ratio of dimethylsiloxane units to methylphenylsiloxane units of 95:5 to 80:20, are suitable for the organopolysiloxane composition of the present invention. It is preferably used because it significantly improves the cold resistance and thermal shock resistance of gelled or rubberized products. Note that in the present invention, the organo group does not include an alkenyl group. And as an organo group, an alkyl group,
Examples include an aryl group, a halogenated alkyl group, and a cycloalkyl group.

The viscosity of the component (a) is preferably 50 csL or more at 25°C, since the viscosity of the component is not particularly limited, or if it is too small, the hardness of the crosslinked product of the organopolysiloxane composition of the present invention will increase significantly and the external stress absorbability will become poor. If it is too large, the workability of the composition will be poor, or the crosslinking of the composition will be slow.
Jcst or less is preferable.

Component (b) acts as a crosslinking agent for component (a). Examples of the triorganosilyl group at both ends include a trimethylsilyl group, a trimethylphenylsilyl group, a nophenylmethylsilyl group, a trimethyloctyl group, and a trimethyl(3,3,3-trifluoropropyl)silyl group. As the main side Olga/hydrodiene polysiloxane, methylhydrononine polysiloxane, trimethylsiloxane/methylhydrodiene siloxane copolymer 1, trimethylsiloxane/methylphenylsiloxane/methylhydrothene siloxane copolymer, trimethylsiloxane・Nophenylsiloxane/methylhydrodienesiloxane copolymer, methyl (3,3,3-trifluoropropyl)
A siloxane/methylhydrothene siloxane copolymer is exemplified. Examples of the organohydrothenecyclopolysiloxane include tetramethyltetrahydrodienecyclotetrasiloxane and pentamethyltrihydrodienecyclotetrasiloxane.

(b) It is necessary that at least three silicon-bonded hydrogen atoms exist in the component.

(b) The viscosity of the component is not particularly limited, but if it is too small, it will easily volatilize, so it is preferably 1 csL or more at 25°C, and the upper limit is 10 csL or more at 25°C.
It is 000cst.

Component (B) has the following formula: [Equivalent of silicon-bonded hydrogen atoms in component (B) 1/[Equivalent of silicon-bonded vinyl group in component (A) 1 = 0.2/1 to 6/1] is added in a suitable amount. If this equivalent ratio is less than 0.271, the organopolysiloxane composition of the present invention will not even gel sufficiently,
This is because if it exceeds 1, it becomes extremely hard and cannot absorb external stress. This equivalent ratio is 0.2/1~0
．． When the ratio is 9/1, the organopolysiloxane composition of the present invention is crosslinked and becomes del-like, and this equivalent ratio is '0.9.
/1 to 6/1 means that it is rubber-like.

Component (c) functions to promote crosslinking by addition reaction between component (a) and component (b). This includes platinum fine particles,
Platinum black, chloroplatinic acid, complex salts of platinum and olefins, platinum alkoxide.

A platinum vinyl siloxane complex salt is exemplified. (a) Ingredients,
Platinum vinyl siloxane complex salts are preferred in terms of compatibility with component (b), and ν1°.component (c) only needs to be present in a so-called catalytic amount; specifically, the amount of platinum in m paraboloids is 0.5 It is preferable that it is contained in an amount of 50 ppm.

Only one kind of components (a) to (c) may be used, or two or more kinds may be used in combination.

The organopolysiloxane composition of the present invention is produced by uniformly mixing components (a) to (c).

From the viewpoint of workability, the viscosity of the composition is 50 to 25°C.
200,000 cst or preferred. (a) Ingredients ~ ())
) Since crosslinking begins when the components are mixed, it is preferable to mix them immediately before coating the semiconductor device. (b) Ingredients and (
It is also preferable to store the composition obtained by mixing component (c) and component (b) separately and mix them immediately before coating the semiconductor device.

The organopolysiloxane composition of the present invention contains additive reaction retarders such as organic nitrogen compounds, alkyne alcohols, and alkyne alcohols that adversely affect the properties of semiconductors. , methylvinyltetrancrosiloxane.

Inorganic fillers, such as hume silica, quartz fine powder;
Organic fillers, such as polyimide powder; polysiloxane reinforcing agents, such as low polymerization degree methylvinylpolysiloxane, siloxane/methylvinylsiloxane copolymers; adhesion promoters such as silane coupling agents; pigments, such as Carbon black, iron oxide, titanium oxide, etc. may be added.

By adding the above-mentioned addition reaction retarder, it becomes possible to extend the time required to mix the components (a) to (c)/&: until they are applied to the semiconductor device, making it significantly easier to use.

If an appropriate addition reaction retarder is selected and added in an appropriate amount, even if components (a) to (c) are mixed, crosslinking will hardly proceed at room temperature, and rapid crosslinking will occur when heated and tightened. It becomes bridging or rubbery.

The organopolysiloxane composition of the present invention has a total content of uranium and thorium in the composition of l 1
) pb or less. By being 1 ppb or less,
Packaging materials used in semiconductor devices during operation;
For example, by transmitting alpha rays generated from radioactive substances contained in ceramic sealing materials or resin sealing materials, it becomes possible to maintain the performance of a semiconductor element by 4T. Further, it is preferable that the total amount of alkali metal ions, such as sodium ions and potassium ions, in the composition is 2 ppm or less by weight.

Semiconductor devices to which the organopolysiloxane composition of the present invention is applied are mainly MOS dynamic random access memories (RAM), read-only memories (ROM), and charge couple devices (CC).
D) Static memory, highly integrated bipolar semiconductor devices, hybrid ICs mounting these semiconductor devices, and individual semiconductors such as Trannos P, Cyxter, and 7 Otocouplers.

The organopolysiloxane composition of the present invention crosslinks on the surface of a semiconductor element at room temperature or under heat to form a gel-like or rubber-like form that adheres closely to the semiconductor element, protects the semiconductor element from moisture and external stress, and protects the semiconductor element from moisture and external stress. Especially when VLSIs are in operation, alpha rays are emitted from trace amounts of radioactive materials contained in their packaging materials! 1', it has the characteristic of maintaining the performance of guiding element-t.

Next, an example of the present invention will be described. In the examples, "parts" refers to parts by weight, and "parts" refer to parts by weight.
) Ill J means the value in weight units, and the viscosity is the value at 2S'C.

Example 1 Dimethylpolysiloxane end-blocked with dimethylvinylsilyl groups at both ends (viscosity 2,000 cst) 100 parts 9 Methylhydrodiene polysiloxane endblocked at both ends with trimethylsilyl groups (viscosity 30 csL) 0.5 parts [(Equivalent weight of silicon-bonded hydrogen atoms)] /(equivalent weight of silicon-bonded vinyl group)=0.
1 which is 65/1 and a platinum vinyl siloxane complex salt obtained by the reaction of chloroplatinic acid and tetramethyldivinyldisiloxane in an amount corresponding to 2 pp+n of the present composition based on the weight of platinum, and defoamed under reduced pressure. Viscosity 1800c
A colorless transparent liquid of st was obtained. In addition, for each component, the content of uranium and thorium is selected to be as low as possible, and the total content of both elements in this composition is Q, 21+1)
b. Further, the total content of alkali metal ions such as sodium and potassium was 0.1 ppm or less.

The above colorless transparent liquid increases the density of MOS to 16 bits.
When the surface of a type RAM element was coated and left at room temperature for 60 minutes, it turned into a gel and adhered closely to the element surface and bonding wire.

Thereafter, after sealing with an epoxy resin composition, the soft error rate of the memory element was measured and found to be 85 fits. The soft error rate with only epoxy resin sealing without silicone coating was 3.8 x 106 fits.

Next, after coating with this composition, the elements sealed with epoxy resin were heated at -55°C/1 hour and 15G'C/1
When a thermal shock test was conducted, no breakage of the bonde/fugu wire was observed even at the 200th cycle.

Example 2 0.1 part of tetramethyltetravinylcyclotetrasiloxane was added to the three-component composition of Example 1, mixed, and defoamed under reduced pressure to obtain a colorless transparent liquid with a viscosity of 1750 csL.

The total content of uranium and thorium in this composition was 0.1 ppb, and the total content of alkali metal ions was 0°lppm or less.

When the surface of a MO8 type RAM element with an integration degree of 16 was coated with the colorless transparent liquid and left at 100°C for 30 minutes, it turned into a gel and adhered closely to the element surface and bonding wire.

Thereafter, the memory element was encapsulated with an epoxy resin composition, and the soft error rate of the memory element was measured and found to be 30 fits.

Next, when a thermal shock test of -55°C/1 hour and 150°C/1 hour was conducted on the device coated with this composition and sealed with epoxy (h1 resin), the holding wire was disconnected even at the 250th cycle. was not seen.

Example 3 Dimethylsiloxane/methylphenylsiloxane copolymer with dimethylvinyl groups blocked at both ends (The molar ratio of dimethylsiloxane and methylphenylsiloxane was 90:10, and the viscosity was 2200 cst) 100 parts rRogenpolysiloxane (viscosity 20 csL) 0. '7 parts [(equivalent of silicon-bonded hydrogen atom)/(equivalent of silicon-bonded vinyl group)=
1 which is 0.75/1 and the platinum vinyl siloxane complex salt used in Example 1 is 5pp of the composition as platinum weight.
m, and defoamed under reduced pressure to a viscosity of 2,
A colorless transparent liquid of 000 cst was obtained. In addition, the content of uranium and thorium in each component is selected to be as low as possible, and the total content of both elements in this composition is 0°1+.
1p1) or less. Further, the total content of alkali metal ions such as sodium and potassium was 0.1 ppm or less.

The surface of an MO3 type RAM element of a bit with an integration degree of 16 was coated with the above-mentioned colorless and transparent liquid, and when it was left at 150° C. for 3 minutes, it turned into a gel and adhered closely to the element surface and bonding wire.

After this, epoxy resin! When the soft error rate of the memory device was measured after being encapsulated with the compound No. 11, it was 25 ft.

Next, when we conducted thermal shock tests at -55°C for 1 hour and at 150°C for 1 hour on the elements coated with this composition and sealed with epoxy resin, we observed that the punching wire was broken even at the 600th cycle. I couldn't.

Example 4 0.1 part of tetramethyltetravinylcyclotetrasiloxane was added to the composition of Example 1, mixed and defoamed under reduced pressure to obtain a colorless transparent liquid with a viscosity of 1740cst. The total content of uranium and thorium in this composition is f
), 051)1]b, and the total content of alkali metal ions was 0.1 ppm or less.

The above colorless transparent liquid (IVI of IGK bit with higher integration)
When the surface of an O8 type RAM element was coated and left for 60 minutes at 51)'C, it turned into a gel and adhered closely to the element surface and bonding wire.

Thereafter, after sealing with an epoxy resin composition, the soft error rate of the memory element was measured and found to be 20 feet.

Next, when we conducted a thermal shock test at -55°C for 1 hour and at 150°C for 1 hour on the device coated with this composition and sealed with epoxy resin, no breakage of the bonding wire was observed even at the 650th cycle. Ta.

Example 5 In the composition of Example 3, (equivalent of silicon-bonded hydrogen atoms)/(silicon-bonded vinyl groups) = 1,50/1
A composition was prepared under the same conditions as above. The total content of uranium and thorium in this composition is 0.
, I H) pb, and the total content of alkali metal ions was 0, 11) l) Il+ or less.

When the surface of a ceramic-sealed N40S RAM element of a bit with an integration degree of 16 was coated with this colorless transparent liquid composition and left at 150°C for 30 minutes, it became rubbery.
It was in close contact with the element surface and bonding wire.

Thereafter, after sealing with fusion glass, the soft error rate of the memory element was measured and found to be 30 fits. Soft error rate of uncoated element is 4.2X10
'Fui.

It was.

Example 6 Dimethylsiloxane/methylphenylonloxane copolymer with methylphenylvinylsilyl groups endblocked at both ends (molar ratio of dimethylsiloxane and methylphenylsiloxane is 93)
= 7 and the viscosity is 500 cst) 100 parts, 2.0 parts of tetramethyltetrahydrodienecyclotetrasiloxane [(equivalent of silicon-bonded hydrogen atom)/(equivalent of silicon-bonded vinyl group) = 2.0 /1 and certain J
The platinum vinyl siloxane complex salt used in Example 1 was mixed with an amount corresponding to 5 ppm of the present composition based on platinum weight, and 0.3 parts of methylbutynol-1, and defoamed under reduced pressure to obtain a colorless transparent liquid with a viscosity of 450 cst. I got it.

In addition, each component was selected so that the content of uranium and thorium was as small as possible, and the total content of both elements in the present composition was set to 0.031)l)+1. Further, the total content of alkali metal ions such as sodium and potassium was 0.11111111 or less.

The surface of a ceramic-sealed MO3RAM element of a bit with an integration degree of 16 was coated with the above-mentioned colorless transparent liquid, and when it was left at 150'C for 60 minutes, it turned into a rubbery state, and the element surface and bonding wire were coated.

Thereafter, the memory element was sealed with fused glass and the soft error rate of the memory element was measured and found to be 20 fits.

Claims (1)

[Scope of Claims] 1(a) A diorganopolysiloxane endblocked with diorganovinylsilyl groups at both ends. (b) Organohydrodiene polysiloxane or organohydrodiene cyclopolysiloxane endblocked with triorganosilyl groups at both ends, and (c) a platinum-based catalyst as main ingredients, [equivalent of silicon-bonded hydrogen atoms in (b) component]/[ (a) Equivalent weight of silicon-bonded vinyl group in component] = 0.2/1 to 6/1,
An organopolysiloxane composition for coating a semiconductor device, characterized in that the component (c) is present in a catalytic amount, and the total amount of uranium and thorium in the composition is 1 ppb or less by weight. 2 Component (a) is a dimethylpolysiloxane endblocked with trimethylvinylsilyl groups at both ends, component (b) is a methylhydrodiene polysiloxane endblocked at both ends with trinotylsilyl groups, and component (c) is a platinum vinylsiloxane complex salt. An organopolysiloxane composition according to claim 1. 3 (a) Component is a dimethylsiloxane/methylphenylsiloxane copolymer with both terminals endblocked with dimethylvinylsilyl groups (the molar ratio of dimethylsiloxane units and methylphenylsiloxane units is 95:5 to 80:20)
and (b) component is a methylhydrodiene polysiloxane blocked with both terminals) and trimethylsilyl group, and ()X)
The organopolysiloxane composition according to claim 1, wherein one of the components is a platinum vinyl siloxane complex salt. 4 [(b) Equivalent weight of silicon-bonded hydrogen atoms in component]
/[equivalent weight of silicon-bonded vinyl group in component (a)]=
Claim range @ 1 item which is 0.2/1 to 0.9/1,
The gel-forming organopolysiloxane composition for coating a semiconductor device according to item 2 or 3. 5 Equivalent of silicon-bonded hydrogen atoms in the component]/
[Equivalent weight of silicon-bonded vinyl group in component (a)] = 0
．． 971 to 6/1, the rubber-forming organopolysiloxane composition for coating a semiconductor device according to claim 1, claim 2, or $3. 6 Viscosity at 25°C as a composition is 50 to 200
1000cst, the organopolysiloxane composition according to any one of claims 1 to 5. 7. The organopolysiloxane composition according to any one of claims 1 to 6, wherein the total amount of alkali metal ions in the composition is 2 ppm or less by weight. 8. The organopolysiloxane composition according to any one of claims 1 to 7, wherein the semiconductor element is a semiconductor element that malfunctions due to alpha rays.