The high vacuum level and vacuum maintenance of device-level Vacuum packaging for silicon microgyroscopes are studied in order to increase the quality factor and its stability. First

the relationship between error signals and quality factor is analysed based on the dynamics equations of silicon microgyroscopes. The air damping of gyroscopes with high quality factor is analysed using rarefied gas dynamics theory. According the early continual test results of quality factor of vacuum packaged gyroscope

the reasons of vacuum level degrade are given. Temperature programmed desorption-mass spectrometry (TPD-MS) is used to measure the contents of the evolution gases for the ceramic packages and the lid. According to the contents of trapped gases

the reasonable getter is chosen to absorb the gases and keep the vacuum level of the cavity. Finally

the device-level vacuum packaging process is improved. The test results show that the quality factor of gyroscope packaged with new device-level vacuum packaging process is about 162660

which is about fourteen times of quality factor of previous vacuum packaged silicon microgyroscopes

and the change of quality factor is less than 0.05% within one year.