Low-Temperature Anodic Bonding for Wafer-Level Al–Al Interconnection in MEMS Grating Gyroscope

In this article, low-temperature anode bonding technology is used to realize wafer-level Al–Al interconnection in MEMS grating gyroscope. The gyroscope structure was fabricated on silicon by micromachining process. Both Al wiring and Al grating were fabricated by magnetron sputtering. Before bonding, the bonded wafers were treated through Ar plasma. The wafer-level bonding was then performed at 330 °C for 15 min under 0.21 MPa with a dc voltage of 1000 V. Acoustic and interfacial tests showed a defect-free Al–Al interconnection. The average bonding strength was as high as 33.94 MPa and the measured resistance was approximate to the theoretical value. The bonded structure was also undamaged under 1500-g acceleration shock. It is concluded that the low-temperature anode bonding for wafer-level Al–Al interconnection will further promote the development of MEMS grating gyroscope.