The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 28, 1984
Filed:
Aug. 19, 1981
John A Kurtz, Gorham, ME (US);
Donald E Cousens, Saco, ME (US);
Fairchild Camera and Instrument Corporation, Mountain View, CA (US);
Abstract
In a method for welding a lead wire or bonding wire from a microcircuit chip mounted on a lead frame to a lead frame finger, the lead frame finger is preheated prior to any substantial electrical or thermal coupling between the lead frame finger and chip. Intense but controlled energy is applied to the lead frame finger at levels which might otherwise damage the IC chip. In one embodiment the lead frame finger is preheated to a temperature below the melting point of the metal comprising the lead frame. Enhanced bonding is thereafter effected by thermocompression bonding etc. In another embodiment the preheating step comprises melting a portion of the surface of the lead frame finger, forming a molten pool or puddle in the surface. Bonding of the lead wire is effected by immersing a section of the wire in the molten pool or puddle. In order to preheat the lead frame finger a controlled pulse train is delivered for arc discharge at the bonding location. Bonding apparatus and circuitry for preforming the method are described.