For several microelectronics applications, Cu/dielectric adhesion is a key reliability issue. Either electroplating or local galvanic coupling under moist operating conditions may result in hydrogen induced interface weakening. The present study compared hydrogen effects on Cu/SiO2 adhesion for sputter deposited films with and without Ti underlayers. Thin Cu and Cu/Ti films ranging from 80-3000 nm have been evaluated. Direct observations of the surface during electrolytic charging have shown no evidence of film/substrate debonding for Cu/Ti systems. In contrast, extensive delaminations have been observed for Cu films. Indentation testing immediately after charging indicated up to 100% decrease in the practical adhesion for Ti/Cu films. The observed effect resulted from a true interfacial fracture energy reduction from 4 to 2 J/m2. Plastic energy dissipation was assumed unaffected as no yield stress changes were detected after charging. Even with the deleterious effect of hydrogen, adhesion strength of Cu/Ti films remained higher than that of non-charged Cu films.
|Original language||English (US)|
|Number of pages||5|
|Journal||Materials Research Society Symposium - Proceedings|
|State||Published - 1999|
|Event||Proceedings of the 1999 MRS Spring Meeting - Symposium on 'Materials Reliability in Microelectronics IX' - San Francisco, CA, United States|
Duration: Apr 6 1999 → Apr 8 1999