3-D, Self-aligned, Micro-assembled, Electrical Interconnects for Heterogeneous Integration

Abstract

It is of great interest to develop an efficient and reliable manufacturing approach that allows for the integration of microdevices each of which is optimally fabricated using a different process. We present a new method to achieve electrical and mechanical interconnects for use in heterogeneous integration. This method combines metal reflow and a self-aligned, 3-D microassembly approach. The results obtained so far include a self-aligned, 3-D assembly of MEMS to MEMS, post-processing which selectively deposited indium on 50 m-thick MEMS structures, and reflow tests of indium-on-gold samples demonstrating 15-45 m resistances for contact areas ranging from 100 to 625 m 2 . 3-D microassembly coupled with metal reflow allows for the batch processing of a large number of heterogeneous devices into one system without sacrificing performance. In addition, its 3-D nature adds a new degree of freedom in system design space. Downward scalability of the method is also discussed.

Micro-manufacturing: research, technology outcomes and development issues

“…Integration of micro-and nano-devices through assembly is still a new area of challenges. A method for achieving electrical and mechanical interconnects for use in heterogeneous integration was combining metal reflow and a self-aligned, 3-D micro-assembly [40], which allows for the batch processing of a large number of heterogeneous devices into one system without sacrificing performance. Micro assembly injection moulding gives another option for joining plastics and some inlay part such as fibre reinforced needle and other elements [41].…”