Selective Al CVD on hydrogen-terminated Si surface

Abstract

Filling deep-submicron via-holes is the most important key technology for multilevel metallization in the future ULSI. The authors discuss the selective deposition of high-quality Al by low-pressure chemical vapor deposition (CVD) using dimethylaluminum hydride (DMAH; (CH/sub 3/)/sub 2/AlH) and H/sub 2/. Deep-submicron via-holes of 0.3 mu m phi with an aspect ratio greater than 3 are completely filled by the selective deposition. For the selective growth mechanism, the authors propose a surface electrochemical reaction model, in which free electrons on the surface catalytically contribute to the reaction. A surface terminated-H atom on the Si surface reacts with the CH/sub 3/ radical in DMAH to produce volatile CH/sub 4/. The H atom of the DMAH remains on the newly deposited Al surface as a new terminated-H atom. The terminated-H atom on the surface reacts repeatedly with CH/sub 3/ radical to deposit Al.<>