"Development of Etching Processes to Fabricate High Aspect Ratio Microstructures in MEMS"

Abstract

The aim of this project is to improve existing microfabrication processes employed in the production and packaging of Micro-Electro-Mechanical-System (MEMS) capacitive accelerometers. The focus will be on etching processes for the development of high aspect ratio (HAR) microstructures using the available facilities of the IPT laboratories in Brazil. Processes will be optimized and standardized, aiming at future production of the accelerometers in scale. HAR microstructures with straight and smooth sidewalls provide high sensitivity in capacitive inertial sensors as well as high density of HAR pathways desired in the MEMS packaging. For the development of these HAR microstructures, sidewall etch must be carefully controlled. Reducing the sidewall etch rate allows deeper etch. Etching processes will be developed and optimized to obtain HAR microstructures, close to or greater than 10, using different combinations of widths and depths. For that purpose, wet and dry etching processes will be evaluated, including deep reactive ion etching and Bosch process. Two demonstrators with HAR microstructures, one with typical dimensions for the MEMS capacitive sensor and one with typical dimensions for the MEMS packaging will be manufactured and characterized. This project will have a duration of two years and is part of the IPT FAPESP-PDIp Grant 17/50343-2, titled "Institutional Development Plan in the Digital Transformation Area: Advanced Manufacturing and Smart Cities (sub-project: Autonomous Inertial Sensing). Results will be disseminated through publications, presentations in congresses and training of other students participating in the project.