Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
1998-10-08
2001-05-01
Moore, Margaret G. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
C528S043000, C428S447000, C156S329000, C257S788000, C257S789000, C257S791000, C257S753000, C257S729000
Reexamination Certificate
active
06225433
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to curable silicone compositions and to electronic components. More particularly, this invention relates to a curable silicone composition that prior to its cure exhibits an excellent degassing behavior and cures to give cured silicone that has an excellent stress-relaxing capacity at low temperatures. The invention additionally relates to highly thermal shock-resistant electronic components that use the subject curable silicone composition.
BACKGROUND OF THE INVENTION
Platinum-catalyzed addition-curing silicone compositions are used as adhesives and sealant/filling agents for electronic components because they have the ability to cure rapidly upon heating or at room temperature with the formation of cured silicone gels or silicone rubbers that have excellent physical and electrical properties. Curable silicone compositions of this type can be exemplified as follows: the curable silicone composition for coating semiconductor elements taught in Japanese Patent Publication (Kokoku) Number Hei 4-2624 (2,624/1992) and comprising diorganovinylsilyl-endblocked dimethylsiloxane-methylphenylsiloxane copolymer, triorganosilyl-endblocked organohydrogenpolysiloxane, and a platinum catalyst; the adhesive taught in Japanese Patent Application Laid Open (Kokai or Unexamined) Number Hei 3-157474 (157,474/1991) and comprising organopolysiloxane containing at least 2 silicon-bonded alkenyl groups in each molecule, organopolysiloxane containing at least 2 silicon-bonded hydrogen atoms in each molecule, an organosilicon compound containing silicon-bonded alkoxy and silicon-bonded alkenyl or silicon-bonded hydrogen, and a platinum catalyst; and the molding material for electrical equipment taught by Japanese Patent Application Laid Open (Kokai or Unexamined) Number Hei 7-192929 (192,929/1995) that comprises vinyl-functional polyorganosiloxane, active hydrogen-containing organohydrogensiloxane, and curing catalyst and that cures to give a gel with a Young's modulus of 10
3
to 10
5
dyne/cm
2
.
The existing curable silicone compositions have recently proven unable to satisfy the demands imposed by the miniaturization of electronic components and the desire for productivity improvements. Thus, while curable silicone compositions as taught in Japanese Patent Publication (Kokoku) Number Hei 4-2624 do provide cured silicone with an excellent stress-relaxing capacity at low temperatures, compositions of this type nevertheless have a very poor degassing behavior and as a result cannot support the highly efficient production of electronic components. In addition, the entrapped bubbles prevent substantial improvements in electronic component reliability. In the case of the cured silicone gels afforded by the cure of a curable silicone composition as taught in Japanese Patent Application Laid Open (Kokai or Unexamined) Number Hei 7-192929, these gels exhibit an excellent stress-relaxing capacity at ambient temperature, but at low temperatures suffer from a diminished stress-relaxing capacity and hence are unable to provide improvements in electronic component reliability.
SUMMARY OF THE INVENTION
The inventors achieved the present invention as a result of extensive research directed to solving the problems described above.
One object of the present invention is to provide a curable silicone composition that prior to its cure exhibits an excellent degassing behavior and that cures to give cured silicone that has an excellent stress-relaxing capacity at low temperatures. Another object of the present invention is to provide highly thermal shock-resistant electronic components that use the subject curable silicone composition.
The present invention is directed to a curable silicone composition, comprising:
(A) 100 parts by weight of an organopolysiloxane containing silicon-bonded aryl groups and at least two alkenyl groups per molecule, and having a viscosity of from 0.01 to 1,000 Pa.s at 25° C., wherein the aryl groups comprise from 1 to 40 mole % of the total silicon-bonded organic groups in the organopolysiloxane;
(B) an organopolysiloxane having a viscosity of from 0.001 to 10 Pa.s at 25° C. and containing at least 2 silicon-bonded hydrogen atoms per molecule, in a quantity sufficient to cure the composition;
(C) a platinum catalyst in a quantity sufficient to cure the composition; and
(D) 0.00001 to 100 parts by weight of an organopolysiloxane having a viscosity of from 0.01 to 10,000 Pa.s at 25° C., with the proviso that when the organopolysiloxane contains aryl groups, the aryl groups comprise less than 1 mole % or more than 40 mole % of the total silicon-bonded organic groups in the organopolysiloxane, and wherein the organopolysiloxane cures to form a silicone having a complex modulus≦1×10
8
Pa at −65° C. and a shear frequency of 10 Hz or a cured silicone having a Young's modulus≦2.9×10
8
Pa at −65° C.
The present invention is also directed to an electronic component, comprising a semiconductor chip, a semiconductor chip attachment element bonded by an adhesive to the semiconductor chip, at least one member that electrically connects the semiconductor chip with the semiconductor chip attachment element, wherein at least a portion of the member is sealed or imbedded with a sealant/filling agent, and at least one of the adhesive and the sealant/filling agent is the curable silicone composition described above.
REFERENCES:
patent: 3623942 (1971-11-01), Yerrick
patent: 5085364 (1992-02-01), Ishikawa et al.
patent: 5429872 (1995-07-01), Nakamura et al.
patent: 5571853 (1996-11-01), Ikeno et al.
patent: 5661198 (1997-08-01), Inatani et al.
patent: 0 195 355 A2 (1986-09-01), None
patent: 0 727 462 A2 (1996-08-01), None
patent: 3-157474 (1991-07-01), None
patent: 4-2624 (1992-01-01), None
patent: 7-192929 (1995-07-01), None
Isshiki Minoru
Mine Katsutoshi
Otani Yoshiko
Yamakawa Kimio
Dow Corning Toray Silicone Co. Ltd.
Milco Larry A.
Moore Margaret G.
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