MEMS Gyro - Maturity assessment of performance and integration

The programme MEMS MATURITY had four goals:

1. To miniaturise the high-performance gyro cell, Gyrix, of the SFWA (Smart Fixed Wings Aircraft) partner
2. To identify the critical parameters of the process that influence the cell performance
3. To assess the impact of the variability of the critical parameters on the cell performance
4. To optimize the process for a repeatable manufacturing and to deliver 20 optimized Gyro cells to evaluate their performances in the sensor operational environment together with the SFWA partner.

To reach these goals, TRONICS used and improved the best state-of-the-art technology for high-performance low-drift inertial sensors. Its main features were:

• Mechanical structures achieved in thick (> 60 µm) single crystal material, starting from thick SOI substrate.
• Mechanical structures etched, in the top thick SOI layer, using a notch-free, highly vertical, accurate 
• Wafer level packaging of the MEMS structure with a silicon cap, bonded through Silicon Direct Bonding, Si-Si or Si-SiO2-Si, avoiding any intermediate heterogeneous material such as a metal sealing.
• Stable high-vacuum environment ensured thanks to long-term-stable high-vacuum (20 years).
• Die-attach of the MEMS chip in the package with non-degasing metallic alloy preform, and stress decoupling structures.

TRONICS has defined a complete work plan to address the main goals of the program. The overall final objective of this programme was also to develop an industrial manufacturing environment for the Gyrix cell object of this programme. This environment met the performances needed for civil aeronautic applications.

During this program, TRONICS also improved the maturity of the Gyrix cell to bring it to a TRL5 level.