Batch fabrication of SMA-actuated polymer microvalves

Abstract

This paper presents novel transfer bonding technologies, which enable batch fabrication of shape memory alloy (SMA) microvalves on the wafer scale. Large-scale integration of SMA thin films/foils in a microsystem is considered to be a major barrier for commercialization of SMA-actuated microdevices. As SMA thin films/foils require different optimized substrates for given process steps, novel technologies for substrate release and for transfer of processed thin films between the different substrates are developed. Different adhesive coatings are used as temporary bonding layers, which provide sufficient bonding strength during processing and, in addition, act as a sacrificial layer. For mechanical interconnection, the technology of heat-activated bonding is introduced. Laser technology is used as a flexible tool for micromachining as well as for selective release of temporary bonding layers. Thus, a new generation of SMA microvalves is realized being compatible to existing microsystems technologies. Copyright © 2008 ASM International® All rights reserved.