Electrochemically deposited thin film alloys for ULSI and MEMS applications

Thin metal films can be electro-deposited for interconnect metallization an d packaging. Electro-forming offers unique properties, such as excellent fi lling of high aspect ratio structures, unique compositions, low temperature processing and low stress films. Electroless forming offers also high sele ctivity. Binary and ternary metallic alloys, such as Ni, Co and Cu, alloyed with iron, phosphorous, boron and refractory metals have been demonstrated to form conducting layers, barriers, and corrosion protection layers. High quality very thin films, with thickness varied between 5 nm and 1 mu m, ha ve been demonstrated with good composition control. After reviewing the bas ic deposition mechanisms vile focus on Co and Ni alloys with refractory met als (e.g., tungsten and molybdenum) and with phosphorous and/or boron. We p resent results of electroless deposition of CoWP as examples for an electro chemical process compatible with silicon technology. Finally we present a p rocess outline for alloy deposition on silicon, or SiO2, for MEMS applicati ons. (C) 2000 Elsevier Science B.V. All rights resented.