Browse Prior Art Database

Enhanced Thermosonic Wire-Bonding Technique

IP.com Disclosure Number: IPCOM000037944D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Conru, AW: AUTHOR [+4]

Abstract

Wedge bonds are less reliable than ball bonds and, when formed directly on a resilient substrate may have unacceptable reliability. However, if a wedge bond is made on a large bonding pad first formed at sites to be used, they are reliable.

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Enhanced Thermosonic Wire-Bonding Technique

Wedge bonds are less reliable than ball bonds and, when formed directly on a resilient substrate may have unacceptable reliability. However, if a wedge bond is made on a large bonding pad first formed at sites to be used, they are reliable.

Referring to the cross-sectional figure, site B is prepared by making a ball bond 10 followed by breaking the bond wire off at the ball. A thermosonic wire ball bond 2 is made at site A to substrate 4, e.g., an integrated circuit chip terminal. The ball bonds are made by transmitted ultrasonic energy through wire capillary tip 6 which forms a good bond between ball 2 and hard substrate 4 under the whole 360 degrees of capillary tip 6. Capillary tip 6 is then lifted and moved to secondary bond site B forming a loop of wire 8. During the bonding of wire 8 to ball bond 10, bonding energy is applied through less than 180 degrees of tip 6 to wire 8 and a wedge bond is formed.

The secondary wedge bond is formed directly over the first ball bond 10 resulting in a final bond structure having enhanced reliability. The preparation bond 10 is usually made larger than a normal ball bond area to give wide tolerance to wedge bonding tip locating operations.

Disclosed anonymously.

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