Technology Development for MEMS: A Tutorial

Silicon sensors date back to before 1960 with early Hall and piezoresistive devices. These used simple processing that was part of the early integrated circuit (IC) industry. As the IC industry developed, silicon sensors could benefit from the technological advances. As silicon sensors advanced, there came the need for new technologies specifically for microsystems. This led to a range of 3-D structures using micromachining and enabled the development of both sensors and actuators. The integration of sensors with electronics on a single chip also presented new challenges to ensure that both sensor and electronics would function correctly at the end of the processing. In recent years many new technologies and new materials were introduced to enhance the functionality of microsystems. Some sensors are still based on silicon, but others introduce new materials such as carbon nanotubes and graphene. Technologies that have been used in other applications for many years are now integral part of the microsystem technology portfolio. These include screen printing and inkjet printing. Moving more into the third dimension, 3-D printing presents many new opportunities to fabricate novel structures on a silicon substrate. This tutorial focuses on the additional technologies which have been developed to supplement standard IC processes to create MEMS structures.