A novel lift off process and its application for capacitive tilt sensor

This paper presents a novel bi-layer (top image resist Shipley S1808 and bottom liftoff resist LOL2000) lift off process for patterning 3D devices. Resists are coated and patterned with an overhang profile on substrate before it is etched and before the film deposition. The key feature of the new lift off process is to create a resist undercut profile, which should be deep enough to reduce step coverage and durable to aggressive substrate etchant. Two-step development method was demonstrated effective. The resist profile is optimized by development time in the two step development process. Proposed lift off process was successively used for fabricating quartz based capacitive tilt sensor.