A monolithic fabrication process for a micro-flow heat transfer channel suspended over an air layer with arrays of micro-sensors and heaters

The objective of this work is to develop a surface micro-machining process that can be used to fabricate a heated micro-channel integrated with an array of both the pressure and the temperature sensors along the channel. With an air layer made underneath the channel for the purpose of insulation, this micro-channel can provide gas flow with measurement of both the local pressure and temperature distribution along the channel flow direction. This heated small size micro-channel can be used to study the channel flow and heat transfer process at the rarefied condition. The entire fabrication process is very complicated which has used a total of 21 photo masks and taken more than 320 times of fabrication procedures. Therefore, the channel has to be carefully designed and preliminary fabrication test has to be done before starting the complete fabrication process. The design consideration and fabrication procedures will be presented. Some of the difficulties encountered during the fabrication process will be discussed.