Gray-Scale Lithography for MEMS Applications
Abstract
Micro-electro-mechanical systems (MEMS) fabrication technologies originated directly from integrated circuit (IC) fabrication. IC devices require only two-dimensional or planar structures to be fabricated because there are no mechanical operations taking place. Therefore, structures fabricated for MEMS devices have been traditionally designed with nominally vertical sidewalls (anisotropic etching), undercut sidewalls (wet isotropic etching), or sidewalls that have limited angles due to the crystallographic orientation of the substrate (wet anisotropic etching). A three-dimensional (3-D) structure in this paper pertains to arbitrarily sloped sidewalls in silicon. That is, a sidewall fabricated as vertical or sloped with a desired angle or profile. A 3-D technique could enhance the efficiency, reliability, and overall performance of various power MEMS devices. Such enhancements could be nozzle and diffuser elements in fluidic devices, trenches designed with specific sidewall profiles for ball bearing devices, and aerodynamic structures for rotary applications. A technique called gray-scale lithography is applied using a one-level development process to create 3-D structures in photoresist. This technique utilizes planar processing and provides additional flexibility that is not supported in conventional IC fabrication technologies. The key components for the development of MEMS-based gray-scale lithography are presented.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2006
- Accession Number
- ADA447924
Entities
People
- Christopher M. Waits
- Madan Dubey
- Reza Ghodssi
Organizations
- United States Army Research Laboratory