TY - JOUR
T1 - Environmental effects on Cu/SiO2 and Cu/Ti/SiO2 thin film adhesion
AU - Tymiak, N. I.
AU - Li, M.
AU - Volinsky, A. A.
AU - Katz, Y.
AU - Gerberich, William W
PY - 1999
Y1 - 1999
N2 - 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.
AB - 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.
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U2 - 10.1557/proc-563-269
DO - 10.1557/proc-563-269
M3 - Conference article
AN - SCOPUS:0033283639
SN - 0272-9172
VL - 563
SP - 269
EP - 273
JO - Materials Research Society Symposium - Proceedings
JF - Materials Research Society Symposium - Proceedings
T2 - Proceedings of the 1999 MRS Spring Meeting - Symposium on 'Materials Reliability in Microelectronics IX'
Y2 - 6 April 1999 through 8 April 1999
ER -