Thursday, February 5th, 2009
Microbridge Technologies, the inventor of passive, analog, MEMS-based precision IC calibration products known as rejustors, announced it has successfully closed an internal round of funding to build out a new presssure sensor family of chips. “The company will launch a line of Micro-Flow pressure sensors that achieve new levels of performance for a wide range of differential pressures,” said Dr. Adam Chowaniec, Chairman of Microbridge Technologies. “With on-chip signal conditioning and amplification, this family of gas pressure sensor chips can address full-scale pressures from tens of Pascal to thousands of Pascal, all with a 0.1 Pascal resolution.”
“No new materials or unit processes were developed,” said Bob Frostholm, Microbridge Technologies vice president of marketing, strategic alliances, and business development. Instead, established 1µm-node unit-processes and materials running at foundry partner XFab have been integrated in a new flow. Since the company’s rejuster is MEMS-based, it is relatively straightforward to imagine combining a rejuster with a pressure sensor as a single-chip (see Figure).
The rejustor uses a polysilicon resistor to heat and modify the grain structure of an adjacent polysilicon trim resistor. University of Freiburg researchers in 2001 reported on the operation and characterization of micromachined CMOS microstructures with integrated polysilicon heaters at temperatures up to 1200K. Also, ST has recently patented an irreversible method to reduce the value of an integrated poly resistor, by subjecting the resistor to a stress current. In all cases, the resistance varies with changes to the poly grain structure; from first principles we know that larger grains reduce resistance, while voids in grain boundaries increase resistance.
Microbridge will sell these new chips in die form to sensor manufacturers, with a full family of products to be announced around the time of the Sensors Expo show in June 2009. The chips reportedly achieve high pneumatic impedances, up to tens of kilo-Pascals, substantially reducing demands on subsequent packaging operations. “The company is sampling selectively now—under strict NDA—and receiving rave reviews,” claimed Frostholm. –E.K.
Tags: CMOS, foundry, funding, IC, integrated, MEMS, pressure, sensor