DocumentCode :
3221817
Title :
A process for prevention of low temperature oxide growth over gold coated backside of silicon wafer
Author :
Khan, Muhib ; Fatemi, Homi
Author_Institution :
Adv. Micro Devices Inc., Sunnyvale, CA, USA
fYear :
1989
fDate :
25-27 Sep 1989
Firstpage :
214
Lastpage :
223
Abstract :
A process for the stabilization of gold film deposited on the back of silicon wafers was developed whereby low-temperature migration of silicon through gold and its oxidation could be prevented. The process consisted of rapid thermal alloying of a sputtered gold film deposited over a fine-ground backside of silicon wafer. The alloying was done at 400°C in an inert environment for a duration of 30 s. The effectiveness of this treatment was demonstrated by improved wetting of an aged, alloyed film with melted gold preform used in gold-silicon eutectic die bonding compared with a nonalloyed specimen. Rapid thermal alloying at 400°C in an inert atmosphere was found to be the most effective means of stabilizing the gold-coated wafer backside. Convection alloying was found to induce some surface oxidation. Surface finish had a notable effect on the resistance to oxidation of the alloyed film; smoother finish was found to be better. Evaporated gold film was found to have a thin underlying SiO2 layer. Such a structure would be a potential hazard to the reliability of die bonding. In such a case, sputtering would be the preferred method of gold deposition
Keywords :
elemental semiconductors; gold; reliability; semiconductor technology; semiconductor-metal boundaries; silicon; 30 s; 400 degC; Si-Au; eutectic die bonding; inert environment; low temperature oxide growth; low-temperature migration; rapid thermal alloying; reliability; sputtering; surface finish; wetting; Aging; Alloying; Gold; Microassembly; Oxidation; Rapid thermal processing; Semiconductor films; Silicon; Surface resistance; Temperature;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Electronic Manufacturing Technology Symposium, 1989, Proceedings. Seventh IEEE/CHMT International
Conference_Location :
San Francisco, CA
Type :
conf
DOI :
10.1109/EMTS.1989.68978
Filename :
68978
Link To Document :
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