AlCu Metal Bond Pad Corrosion During Wafer （行业金属债券垫腐蚀在晶片）.pdfVIP

Al-Cu Metal Bond Pad Corrosion During Wafer Saw Al-Cu Metal Bond Pad Corrosion During Wafer Saw Joseph Fauty, Steve Strouse*, Jay Yoder, Carlos Acuna**, and Phil Evard** ON Semiconductor 5005 East McDowell Road Phoenix, Arizona 85008 Phone: 602-244-5022 Fax: 602-244-5714 e-mail: Joseph.Fauty@ *Motorola CE/SSG **Motorola SPS Abstract This paper examines various techniques ON Semiconductor explored which may be used to reduce the extent of bond pad corrosion during wafer saw on product that uses Al-Cu alloys for chip metallization. While the most effective place to preclude bond pad corrosion is in wafer fabrication, wafer lots are processed and delivered to the production floor only to have corrosion discovered as a by-product of wafer saw. The usual result is scrapping of whole wafer lots with attendant loss of wafer costs and production line upsets. The purpose of this paper is to outline various methods explored to minimize corrosion and avoid line shut downs. Some of the methods discussed in this work were successful and some were not, leading to a better process for sawing wafers. Methods explored to inhibit corrosion consisted of effects of machine parameters (time, saw speed, amount of water used, and lighting effects), partial sawing techniques, plus metal and organic coatings (not technically post wafer fabrication processes). Of all the meth ods explored, a final top metal deposition of Al-Si proved the most effective deterrent followed by the partial saw cut technique. tially three types of corrosion that can occur in a wet environ- Keywords: ment that are of interest in microelectronics; namely, • galvanic or dissimilar metal cells