화학공학소재연구정보센터
Thin Solid Films, Vol.320, No.1, 35-44, 1998
CVD Al PVD Al integration for advanced via and interconnect technology
A metallization process that can fill the ever-shrinking vias and form the interconnect at the same time is highly desirable. An integrated Al plug and interconnect process offers advantages of improved electrical performance, and reduced cost of ownership through process simplification for 0.25 mu m and beyond. In this report, an enabling technology that integrates Al deposited by chemical vapor deposition (CVD) with an overlayer of sputtered AlCu is discussed. The ability to deposit in-situ sequential layers without a vacuum break was a key factor in developing a technology for consistent void-free fill of sub-0.25 mu m structures. This approach has resulted in a low resistivity (similar to 3 mu Omega cm), low temperature (< 380 degrees C) via fill process with copper doping of CVD Al. Sub-0.2 mu m via/contact fill with aspect ratio greater than 4 was achieved. This technology was integrated in a two-level 0.35 mu m design rule with conventional BEOL processing. A better than 2x improvement in via resistance was achieved compared to W technology. No problems were encountered with oxide CMP, photolithography or metal etch. Data on via fill capability and electrical performance of the integrated CVD Al/PVD AlCu process is presented. Studies on copper doping of CVD Al are discussed. Investigation of morphology and texture dependence on wetting layer for CVD Al is reported.