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:
Jan. 08, 2002
Filed:
Jun. 25, 1999
Charles F. Miller, Anaheim Hills, CA (US);
John C. Price, Rancho Mirage, CA (US);
West Bond, Inc., Anaheim, CA (US);
Abstract
An improved apparatus and method for forming a fusion ball at the end of a wire protruding from an ultrasonic bonding tool preparatory to making a ball bond to a workpiece includes shielding means for attenuating electromagnetic interference (EMI) emissions from an electrical arc discharge used to form the ball, which EMI emissions may damage sensitive electronic circuitry on a workpiece. In a preferred embodiment, a ball-forming arc discharge to a wire end occurs with a spark chamber in an electrically conductive electrostatic shield and preferably includes a ferromagnetic shield cup surrounding the chamber. According to the method of the present invention, a capillary ultrasonic bonding tool having a severed end of a gold bonding wire protruding from a capillary bore through the tool is moved away from a vertical line of action between the tool and a workpiece. The tool is then moved downwardly to insert the wire end into an opening provided in a shielded spark chamber located above the plane of the workpiece, where an electrical spark arcing from a high voltage electrode to the severed wire end within the chamber delivers a controlled amount of energy to the wire end to form thereat a fusion ball. The tool tip is then moved upwardly to withdraw the wire end from the spark chamber, and moved back to the line of action of the tool tip, preparatory to moving the tool tip downwards along the line of action to bond the ball-end of the wire to a bond site on the workpiece.