Method of immobilizing circuitry fingers
AssigneeSumitomo Bakelite Co., Ltd.
InventorJin-O Choi
Life of this patent
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Abstract
Disclosed is a method of immobilizing the fingers of circuitry. A coating is formed of a liquid adhesive on the surface of a release film in a pattern of strips in positions perpendicular to and across the positions the fingers of the circuitry will have when the pattern of adhesive is bonded to it. The coating is rendered non-tacky and is bonded across and between the fingers and the release film is removed from the coating.
Claims23
A method of immobilizing the fingers of circuitry comprising
- (A) forming a coating of a liquid adhesive in an organic solvent on the surface of a release film in a pattern of strips in positions perpendicular to and across and in between the positions the fingers of said circuitry will have when said pattern of adhesive is bonded thereto;
- (B) rendering said coating non-tacky;
- (C) bonding said strips of coating on said release film across and in between said fingers;
- and
- (D) removing said release film from said coating.
A method of bonding a cluster of integrated circuit chips to a corresponding cluster of lead frames comprising
- (A) forming a coating of an adhesive which comprises a mixture of an organic solvent and a polyimide, polyamic-acid, polyamide, polyamide-imide, or a partially imidized precursor thereof on the surface of a release film in a pattern corresponding to strips across the fingers of each of said lead frames;
- (B) evaporating a sufficient amount of said organic solvent to render said coating non-tacky;
- (C) aligning said pattern with said cluster of lead frames;
- (D) heating and pressing said release film against said lead frames at a temperature of about 80 to 150 degrees centigrade and a pressure of about 6.8 to about 340 kPa such that said adhesive is forced into spaces between said fingers;
- (E) separating said release film from said adhesive;
- (F) hard baking said adhesive at about 200 to about 400° C. until less than 0.5 wt % solvent remains in said adhesive;
- (G) aligning said cluster of integrated circuit chips with said cluster of lead frames;
- and
- (H) heating and pressing said cluster of integrated circuit chips against said cluster of lead frames.
A method of bonding a cluster of integrated circuit chips to a matching cluster of lead frames comprising.
- (A) forming a paste which comprises
- (1) a partially imidized polyamic acid;
- (2) about 40 to about 80 wt % of an organic solvent;
- and
- (3) about 0.1 to about 10 wt % of a thixotrope;
- (B) placing a template on the surface of a release film, said template having aperture therethrough in a pattern of strips in positions perpendicular to and across the position the fingers of said cluster of lead frames will have when said pattern of adhesive is bonded thereto;
- (C) forcing said paste through said apertures onto said release film to form a pattern of said paste on said release film;
- (D) evaporating sufficient solvent from said paste on said release film to render said past non-tacky;
- (E) aligning said pattern of paste on said release film with said cluster of lead frames;
- (F) hot pressing said pattern of paste to said cluster of lead frames at a temperature of about 80 to 150 degrees centigrade and a pressure of about 6.8 to about 340 kPa such that the paste is forced into spaces between said fingers;
- (G) removing said release film from said pattern of paste on said cluster of lead frames;
- (H) hard baking at a temperature sufficient to fully imidize said partially imidized polyamic acid;
- (I) aligning said cluster of lead frames with said cluster of integrated circuit chips;
- and
- (J) heating and pressing said cluster of integrated circuit chips against said cluster lead frames.
Dependencies are inferred from the claim text.