B4.1 - Acceleration Sensor IP-Blocks for MEMS Foundry Surface Micromachining Process

SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
Proceedings SENSOR 2011
B4 - Mechanical Sensors II
R. Knechtel, S. Dempwolf, S. Hering - X-FAB Semicon¬ductor Foundries AG, Erfurt (Germany), T. Link - Micromountains Application AG, Villingen Schwenningen (Germany), M. Trächtler, J. Dehnert, D. Hoffmann - HSG-IMIT, Villingen Schwenningen (Germany)
271 - 276


Using silicon based MEMS technologies, the cost-efficient production of inertial sensors has become possible in recent years. Meanwhile ready to use MEMS foundry technologies allows both the manufacturing of high volumes and small series. Since the technology is developed and provided by the MEMS foundry the main challenge for bring an inertial sensor to the market is the chip design, for which MEMS design experiences are required. To give customer support at this point IP (Intellectual Property) design blocks for acceleration sensor were developed, processed and characterized. They are allowing customer specific modification (e.g. for the pad layout) and are ready to implement in specific solutions.

The market and application analysis has shown that there are needs for acceleration sensors in different measurement ranges: low g-Sensors with high precisions which can sell for higher prices (larger chip size tolerable), high g-Sensors which are less sensitive but cost sensitive and medium range sensors. IP blocks for these were designed related to the X-FAB MEMS foundry technology for surface micro-machined inertial sensor. In this design phase FEM was very important to meet the requirements on the mechanical behaviour (resonance frequency, band with, damping, linearity, mechanical shock) and on the final electrical function (base capacity, capacity change related to measurement signal).

After assuring a complete fulfilling of the design rules the IP blocks were processes in the MEMS foundry technology which is based on SOIWafers. The mechanical structures are etched out of single crystalline silicon and have by this excellent mechanical properties. Since the mechanics capped at wafer level the chips could be mounted in standard packages and characterized using a standard signal conditioning electronic. The mechanical acceleration movements were provided by a turn table and a shaker system. The characterizations which was done at different temperatures shows very good acceleration sensor behaviours, all target defined in the design phase were reached with these IP-Block samples.