Patent ID: 8058144

Claim:
A method for bonding a cap wafer to a MEMS wafer to form a hermetically sealed cavity between the cap wafer and the MEMS wafer, comprising: a. applying a glass bonding agent to the cap wafer and removing organic material in the glass bonding agent; b. cleaning the cap wafer/glass bonding agent combination with an oxygen plasma to remove lead; and c. bonding the cap wafer to the MEMS wafer including: (i) bringing the cap wafer/glass bonding agent combination into contact with the MEMS wafer, the glass bonding agent forming the bond between the cap wafer and the MEMS wafer; and (ii) heating the cap wafer/MEMS wafer combination in a capping gas atmosphere at a given temperature and a given pressure such that the percentage of hydrogen molecules in the sealed cavity after bonding, when the temperature of the cavity equals 20 degrees centigrade, multiplied by the cavity pressure, measured in atmospheres, is greater than 1.