Theory, Fabrication, and Characterization of MEMS Devices: An Interdisciplinary Course for Mechanical Engineers
Authors: Flachsbart B. R. , Prakash S. , Yeom J. , Wu Y. , Mozsgai G. Z. , Leseman Z. C. , Wong K. , Connell C. R. , Correa E. J. , Hansen M. R. , Shannon M. A. 
Published: April 2008

The need to provide students with hands-on instruction in the fabrication of Microelectromechanical Systems (MEMS) led to the development of an upper-undergraduate, introductory-graduate, laboratory course offered each spring in the Department of Mechanical Science and Engineering (MechSE). The laboratory is taught in a class 100 cleanroom located in, and operated by, the MechSE department. Fabrication and testing of two MEMS device projects, a piezoresistive membrane pressure sensor and a microfluidic logic chip, facilitate the teaching of standard fabrication procedures, fabrication tool operation, and cleanroom protocols. The course appeals across disciplines as evident by half the students coming from other departments (chemical engineering, chemistry, material science, physics, electrical engineering, aeronautical engineering, etc.). The course also serves to attract prospective graduate students as many students continue to use the cleanroom in their graduate level research. This course broadly covers MEMS fabrication theory while maintaining a focus on practical understanding and laboratory application of that theory. The lecture is tied closely to the laboratory work by covering the tool and procedure theory that is used in the lab each week. An exciting aspect of the course is the hands-on learning experience the students get by independently operating the fabrication equipment themselves, including metal deposition tools, reactive ion etch (RIE) tools, lithography tools (spinners, mask aligners, etc.), and bath etchers and cleaners. Safety is an important aspect of the course where students are tested on safety protocol, Material Safety Data Sheet (MSDS) and National Fire Protection Agency (NFPA) familiarity, personal protection procedures, etc. The students also learn benchmark fabrication procedures including standard cleaning protocols (with ultrasonics), the Bosch RIE etching of silicon microstructures, and anisotropic etching of silicon. The piezoresistive membrane pressure sensor project facilitates an understanding of the residual stresses involved in thin-film deposition, stress-strain relationships, and signal analysis for transduction mechanisms. The microfluidic logic chip project, a chip of logic gates (NAND, NOR, etc.) and a half-adder, facilitates understanding fundamental principles of microfluidics, the Navier-Stokes equation, and flow in microchannels. This course, originally sponsored by Intel Corporation, prepares Mechanical Engineers in a multi-disciplinary environment to learn both the practical fundamentals and the theoretical basis of basic and advanced microfabrication that goes beyond the usual CMOS fabrication theory and methodology taught in Electrical Engineering for the microelectronics bound students. As evident from its popularity, the course also serves to excite and equip students for the important Mechanical Engineering field of MEMS.