Sensors such as accelerometers are important components in the automotive industry. To compete on the world market, a new class of sensors is required with better performance, reliability, system (bus) compatibility, interchangeability, and at lower cost levels.
The main objectives of MAXIMA are to:
- establish the compatibility of micromachining techniques with existing industrial IC fabrication lines
- develop a complete process flow for monolithic integrated smart sensors (MISS)
- develop material characterisation methods, design rules and software tools for MISS
- establish basic sensor technologies for a broad field of MISS applications
- make MISS technologies for a broad field of MISS application
- make MISS technologies available for SMEs
- strengthen the position of the automotive industry.
Processes for the deposition and wet etching of various oxides as the sacrificial layer and for deposition and dry etching of polysilicon from 1 micron up to 10 micron thickness have been developed. Relevant parameters for accelerometer designs have been determined with specially designed test structures and equipment. Two different process flows for the integration of the sensors into a bipolar complementary metal oxide semiconductor (BICMOS) process have been developed, 24 different capacitive sensors for x, y and z axis measurement without on-chip electronics were fabricated with subsets of the integrated process flows. Different approaches for sensor signal detection and force feedback have been investigated in detail. Various single chip three-axis accelerometers with on-chip electronics were designed and fabricated with the developed process flows. Application specific tests were performed at SEAT.
Silicon-based sensors using micromachining technologies to create the sensor function are the most promising candidates to fulfil these requirements. Monolithic integration with microelectronic circuits creates a unique possibility to achieve an improved quality of sensor systems. A demonstrator 3-D accelerometer will be fabricated and tested in the automotive environment. Applications are expected in four major areas: air-bag and safety restraint systems; adaptive and active suspension systems; braking and tracking control; and navigation and guidance.