Research On The Key Technology Of MEMS Vacuum Packaging

Athough the design and fabricating of the MEMS chips have already been well developed,the application of these chips is not full spread because of the lag of the MEMS packaging technology.Among the MEMS packaging technology,the vacuum packaging is an important technology needed to be investigated in no time for the needs of most MEMS devices which had locomotory parts or vacuum cavities. Only after vacuum packaging,these devices could achieve good performances.However,the vacuum packaging technology both at home and abroad is not proved to be effective and still remains some problems such as high cost,lack of reliability and so on.Therefore,this thesis makes some research on the theory,equipment and technology of the vacuum packaging.The detail and innovative work presented in this thesis are summarized as fellows: Firstly how the desorption of the gas absorbed by the packaging materials and the leakage of the gas through the micro holes affect the vacuum in the packaged cavities is analized by applying the related vacuum physics theories.and researches are made on the technical principles of the device level and wafer level of the vacuum packaging. Secondly an equipment has been developed for MEMS vacuum packaging.It well satisfies the needs of the vacuum packaging since the possession of some functionalities such as vacuum acquisition,heating and temperature control,cooling, optics alignment,and force loading . Then based on the theory that vacuum could promote the quality factor of the MEMS devices,the necessity of the vacuum packaging for the micro gyro is confirmed.And experiments of vacuum sealing has been carried out with the in-house vacuum packaging equipment to obtain the optimum fabricating parameters.By repeating the best process,the vacuum sealing of the micro gyro is accomplished successfully. Finally experiments of anodic bonding and Au-Si bonding have been carried out to find out the key factors related to the bonding strength,and the most feasible bonding manners are put forward.