| Integration of micro-electro-mechanical systems (MEMS) with pre-fabricated integrated circuits (ICs) has been successfully demonstrated with two commercial IC technologies. High-aspect ratio, single-crystal silicon (SCS) MEMS were post-fabricated next to BiFET operational amplifiers and next to 0.5{dollar}mu{dollar}m CMOS logic devices. In both cases, the ICs were fabricated at commercial facilities using standard production processes, after which the MEMS were micromachined at the Cornell Nanofabrication Facility using standard fabrication tools.; The MEMS process used for this integration work is based on the S scCREAM process and is designed to integrate MEMS with silicon IC technologies, including, but not limited to, CMOS, BJT, BiFET, BiCMOS and others. The process is called I scSAIC (Integration of S scCREAM After Integrated Circuits) and uses plasma-based techniques and two lithography steps to micromachine the SCS substrate next to extant ICs. To demonstrate the functionality and to elucidate possible damage mechanisms, ISAIC MEMS were fabricated on wafers provided by two manufacturers and electrical parameters were compared before and after MEMS fabrication. The devices were (1) AD712 dual precision BiFET OpAmps provided by Analog Devices Inc. and (2) 0.5{dollar}mu{dollar}m CMOS logic devices fabricated by MiCRUS inc. In both cases devices were found to be within specification after processing. These results are in accordance with the literature which indicates that damage to IC's from plasma etch processes is minimal when (1) the ICs are protected by dielectric films and (2) plasma charging effects are minimized with proper design.; Complete integration details for S scCREAM-based MEMS integration are discussed, including: process discussion; fabrication results; applications of integration; S scCREAM design rules; and S scCREAM structure modeling. This work is the result of seven years research in S scCREAM-based MEMS. |
