| abstract |
Tin oxide films are used to create air gaps during semiconductor substrate processing. Tin oxide films disposed between exposed layers of other materials such as SiO 2 and SiN can be selectively etched using plasma formed from H 2 -containing process gas. Etching creates recessed features instead of tin oxide between the surrounding materials. A third material, such as SiO 2, is deposited over the recessed features without completely filling the resulting recessed features, forming an air gap. A method of selectively etching tin oxide in the presence of SiO 2 , SiC, SiN, SiOC, SiNO, SiCNO, or SiCN, in some embodiments, includes plasma formed in a process gas comprising at least about 50% H 2 . And contacting the substrate. Etching of tin oxide can be performed without the use of an external bias on the substrate and is preferably performed at a temperature of less than about 100 ° C. |