Micromachining of Pyrex7740 glass and their applications to wafer-level hermetic packaging of MEMS devices

A new wafer-level process to precisely fabricate regular arrays of deep cavities on the Pyrex7740 glass wafer as well as applications to wafer-level hermetic packaging of MEMS devices are presented. The process is based on the anodic bonding, and the Si substrate is employed as a mold layer to form the shape of the cavity. The appropriate processing parameter is obtained from a series of experiments. Finally, the wafer-level hermetic packaging process of MEMS devices is completed by the second anodic bonding process. The whole process has been carried out with dew point sensors in wafer-level and illustrated in detail.