Micromachining process for microsensor fabrication

MEMS (microelectromechanical systems) are an outgrowth of silicon technology. They are chip-sized systems that have the ability to affect their surroundings and to communicate what they know to the outside world in new and dramatic ways. And they can be made cheaply. In the fall of 1999, the Sensor Systems Center (SSC) was formed at Texas Tech University to capitalize on the growing interest in microsensors and microanalysis systems, the research was focused on the design, fabrication, and testing of wafer-based, compact microanalysis systems.

At SSC, micromachining processes are under development for this purpose. Oxidation, lithography, PCD, CVD, etching are inherited from semiconductor processing and are done using processing tools and characterization equipments housed at the Maddox Laboratory. Bonding process is new and a tailored anodic bonding system has been self-built. Bonding between Si/Si, Si/Glass, and Glass/Glass wafer pairs can be done using these tools. Channels are made in silicon and glass substrate. A bulkmicomachinined accelerometer has been successfully fabricated. More complex and functional microsystems are being developed using these processes.

In this paper these process steps are summarized with theoretical descriptions and actual fabrication examples, experimental results are investigated as well to optimize these process steps.