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:
Nov. 26, 1985
Filed:
Feb. 28, 1983
Fairchild Camera & Instrument Corporation, Mountain View, CA (US);
Abstract
A method and circuits are described for sensing and detecting bond attempts and weld attempts during bonding and welding of lead wire. The method and circuitry are particularly applicable for detecting missed ball bonds and missed wedge bonds during bonding of lead wire between the die pad of a microcircuit chip and the lead frame on which the chip is mounted. A sensor (30) or sensing circuit (42) senses the different characteristic electrical condition of the lead wire (11) following a ball bond attempt and following a wedge bond attempt. A bond attempt indicator (45) indicates high resistance in the lead wire following a missed ball bond while weld attempt indicator (46) indicates low resistance in the lead wire (11) following a missed wedge bond. The lead wire (11) is isolated from uncontrolled contacts with ground potential while the lead wire is held in the bonding tool and bonding machine. Switching circuit (38) electrically switches and couples the lead wire to a controlled ground coupling (27), (52) during ball formation or to a ground isolating voltage source (28 ), (54) for delivering current to the lead wire and establishing a bond sensing and detecting mode following the ball bonding operating mode and wedge bonding operating mode of the bonding machine. The switching circuit (38) is actuated by a control signal (40) from the control signal circuitry of the bonding machine or from independent control circuitry. Time sequence circuitry may also be provided for the control signals.