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:
May. 23, 2000
Filed:
Jan. 15, 1997
Inderjit Singh, San Jose, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A capillary for use in wire bonding has a wire feed bore extending from a top end of the capillary toward a capillary tip. A cavity in the capillary tip is adjacent to and contiguous with a chamfer in the wire feed bore. The cavity defines cavity walls and a recessed tip surface. The cavity can be substantially cylindrical. The recessed tip surface can be tapered relative to a horizontal axis. The portion of the capillary tip outside of the cavity defines a wedge surface which is used for wedge bonding. The cavity allows for precision small ball bonds which are strong and which have an even bonding surface distribution. The cavity molds the ball bond into a shape substantially similar to the shape of the cavity. Although there is some flash of wire metal out from the cavity, the flash is minimized and the ball bond diameter is held to a minimum by the molding effects of the cavity. The size of the ball bond is dependent only on the size of the free air ball. The size of the ball bond is not dependent on the power, force, and time duration of the ultrasonic energy delivered during formation of the ball bond. The cavity provides a strong ball bond by allowing for even distribution of bonding on the bonding surface. The intermetallic formation at the interface of the wire metal and bond pad metal is evenly distributed.