Development Trends and Cleanroom Concepts in the Industrial Production of Microelectromechanical Systems

During the past few years, remarkable efforts have been made in the field of microscale sensors, actuators, and microelectromechanical systems. Due to advance in solid state and micromachining technologies, significant advances in designing, fabricating and testing of microminiaturised devices have been achieved at laboratory level. However, the technical and economical realisation of microelectromechanical systems at an industrial level is considerably impeded by the lack of satisfactory device technology for the industrial production. A production concept for the industrial production of hybrid microelectromechanical systems, the MicroFab concept, was developed. This concept separates the microdevice fabrication into four different tasks: firstly design and production planning by the microsystems manufacturer, and secondly fabrication of the signal processing part by an IC-manufacturer. The third task involves the microsystem manufacturer, who executes the know-how-bearing process st eps. The less efficient microstructuring process steps are executed by external technological service centres. To demonstrate the feasibility of this approach, the design concept of a micorfabrication process centre, which includes tasks like transport and handling, processing, cleaning, testing, and storing was developed and investigated. On the one hand, special attention was given to highly modular clean production concepts within the microfabrcation process centre, on the other hand to contamination-free transport to and from external service providers and to contamination-avoidance during microassembly and handling. Crucial point for the successful application of the MicroFab concept is the implementation of homogenous mechanical, environmental and information interfaces within the microproduction process centre as well as to external providers of technology.