Improvements in MEMS gyroscope production as a result of using in situ, aligned, current-limited anodic bonding

Control of the bonding process is important in the high volume manufacture of MEMS gyroscope. This paper reports on the use of in situ, aligned, current-limited anodic bonding to enable the required device throughput and control of the bonding process. Statistical analysis of stress-sensitive output parameters of the gyroscope is used to quantify the benefits of different bonding procedures. Current limiting is shown to improve device-to-device reproducibility and the in situ capability of the combined aligner-bonder equipment enables high-throughput manufacturing and yield improvements. Cycle times for the aligned anodic bond process were reduced from 40 to 20 min, and wafer bow reduced by 20%. This reduction in wafer bow translated directly into improved device performance and reproducibility.