Skip to main content

Silicon surface micromachined gyroscope for mass market applications

Objective

- Installation of a club of (automotive) end users to agree on a broadly based specification.

- Development of a surface micromachined gyroscope device for automotive applications with high resolution angular rotation (0.5 °/sec) and offset stability (0.1...1°/sec), based on the TPSM process.

- Reduction of thick polysilicon stress, stress gradients and surface roughness to extend the application of the TPSM process to the gyroscope.

- Introduction of a buried polysilicon layer with low electrical resistivity into the TPSM process. This layer is needed for capacitor fields underneath the moving gyroscope structures which provide the sensor signal, and for electrical contacting.

- Improvement of the high density plasma etching process. This is the key process for silicon surface micromachining and determines the quality of the sensor structures.

- Development of electronic circuitry to drive the sensor oscillation and detect the yaw rate signal. A breadboard version of the evaluation electronics will be debugged and optimised, serving as the basis for a monolithically integrated circuit chip.

- Fabrication of a demonstrator with sensor element and electronic circuit chip mounted together in a metal housing which will be evacuated and hermetically sealed.

A surface micromachined one-axis gyroscope mainly for automotive applications with strong market penetration is to be developed based on Thick Polysilicon Surface Micromachining (TPSM) technology. The basic process will be improved to meet the stringent requirements of the gyroscope application with respect to critical material and process parameters (control of active polysilicon layer stress and stress gradients, surface roughness, inclusion of a buried polysilicon contact layer, accuracy and aspect ratio of the microstructuring process, sacrificial etching techniques, housing and vacuum encapsulation of the sensor elements). Driving and evaluation circuitry will be realised on a separate chip and combined with the sensing device by hybrid mounting.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Robert Bosch GmbH
Address

70049 Stuttgart
Germany

Participants (3)

Consejo Superior de Investigaciones Cientificas Centro Nacional de Microelectronica
Spain
Address
Cnm Sevilla
Avde Reine Mercedes S/m
Surface Technology Systems
United Kingdom
Address
Prince Of Wales Industrial Estate
NP1 5AR Abercarn
Volvo Car Corporation
Sweden
Address
Dept 98830 Electrical Engineering
S-40508 Gothenburg