Study Of Silicon Micro-mold Manufacturing Process Based On Plasma Activation Bonding

Silicon direct bonding (SDB) technology is a quite fast growing new micro-machiningtechnology in wafer bonding technique. It has been used in an increasingly wide range ofapplications in the manufacturing of micro-sensors and actuators. Many advantages are foundin SDB: the two bonded silicon wafers are not limited to crystal orientation, conductivity typeor resistivity; SDB has no intermediate layer, and bonded wafers have the same coefficient ofthermal expansion, so the bond interface will not produce internal stress when temperaturechanges; SDB can be used to form micro-structure, cavity and films, and et al.With growing demands of high-performance complex micro-structure for the MEMS(Micro-Electro-Mechanical Systems) devices, key issue is to develop micro-mold processingmethod, which should be efficient and high-precision. Amorphous alloy, which has thecharacteristic of superplastic forming in its supercooled liquid region, shows greatdevelopmental prospect. Silicon micro-mold is ideal for using amorphous forming to massproduce MEMS devices. Based on amounts of experimental research for the use of SDB anddeep silicon etching technology, we have developed the process technique of producing2Dand3D silicon micro-mold. Overall research work and achievements are as follows:1. Based on studies of plasma-activated SDB process，stable silicon bonding wafers withhigh strength and high bonding rate are obtained. In deep study of the mechanism ofcausing defects in the bonding interface, it is proved that reducing activation time caneffectively reduce excessive by-products in the the bonding interface after annealing,which contributes to obtain stable, high quality bonding wafers;2. Good2D silicon micro-molds and ideal3-layer silicon bonding wafers are obtained.With the amorphous alloy superplastic forming process, amorphous alloy micro-gearsare made by the2D silicon micro-mold. Based on experiments, we suggest reasonablesolutions to solve the problems of making three-dimensional silicon micro molds;3. Testing the silicon micro-molds’ bonding quality is discussed, bonding strength valueand clear defect distribution can be obtained respectively. Using the new imageprocessing technology, accurate bonding rate value is obtained.