A MEMS fabrication technique for non-planar substrates

The integration of MEMS sensors, actuators, and IC devices onto macro mechanical parts is a critical technology necessary for the potential realization of intelligent mechanical structures. The current planar fabrication methods offered by the MEMS/IC industry restrict the possibility of integrating micro devices onto contoured (non-planar) mechanical structures. We have developed a lithographic technique to directly fabricate micron-sized sensing and actuation structures onto a cylindrical surface. This novel technology includes the development of flexible masks, photoresist spraying technique, and customized alignment systems. Results indicate that line resolution of <5 /spl mu/m is possible for structures on the surface of a 2" (5.08 cm) long cylinder with a diameter of 1.25" (3.175 cm). This paper describes the procedures developed to fabricate sacrificially release micro structures onto a cylindrical surface. The performance of some micro thermal actuators and shear stress sensors on a quartz cylindrical substrate are also presented.