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Proceedings Paper

Wirebond pull test failures at rapid thermal processes (RTP) TiN/BPSG interface
Author(s): David L. O'Meara
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Paper Abstract

Ultrasonic wirebond pull test failures were identified on 7 of 30 development lots receiving a rapid thermal processed (RTP) titanium nitride (TiN) barrier metal (as part of the metal film stack) over a 16 month period. In some cases, the pull test failures occurred at forces less than the minimum requirement of 2.5 grams. The failures were intermittent in wafer location and resulted in exposed borophosphosilicate glass (BPSG) under the metal pads. No trends were found with product type, process dates or sequence, or processing equipment, (BPSG, metal deposition or RTP). The faulty films did not fail tape peel adhesion tests, and thus could not be identified by that technique. The problem was found to be related to an interaction between the titanium and BPSG during the RTP nitridation process. Our experiments, analytical studies and literary surveys suggest that a dopant in BPSG either embrittles the TiN (or interfacial glass) through consumptive segregation or enhances the BPSG flow properties during RTP, creating a weakly adhering interfacial region after the ultrasonic action of the wirebond process. Further experiments refute the reflowing BPSG theory and somewhat substantiate the dopant segregation/embrittling phase theory.

Paper Details

Date Published: 9 September 1994
PDF: 15 pages
Proc. SPIE 2335, Microelectronics Technology and Process Integration, (9 September 1994); doi: 10.1117/12.186051
Show Author Affiliations
David L. O'Meara, Hughes Technology Ctr. and Philips Semiconductors (United States)

Published in SPIE Proceedings Vol. 2335:
Microelectronics Technology and Process Integration
Fusen E. Chen; Shyam P. Murarka, Editor(s)

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