Micro pinball game demonstrating an easy MEMS transfer process using room temperature plasma bonding

An easy wafer level transfer process for fabrication of electrostatically actuated structures such as bulk micromachined motors or cantilevers is described. The actual structures were fabricated by dry etching of a donor wafer, transferred to a handling wafer using room temperature oxygen plasma assisted bonding and then revealed through etchback of the donor wafer. Notching during the dry etch was avoided since there is no need for a buried oxide etch stop layer. Etch depth differences after the dry etch were eliminated in the etchback step. The process was used to fabricate MEMS demonstrators in the form of micro pinball games and microelectromechanical wobble motors. This process is a low cost alternative to using SOI wafers and it also circumvents some of the problems of deep dry etching that arise when using buried etch stop layers as in the case of SOI wafers. Another advantage of using SOI wafers is that double-sided micromachining becomes less complicated.