A single-wafer-based single-sided bulk-micromachining technique for high-yield and low-cost volume production of pressure sensors

This paper presents a novel single-wafer-based single-sided bulk-micromachining piezoresistive pressure sensor that features highly uniform diaphragm thickness and ultra-small size. Without double-side alignment and wafer bonding needed, the single-crystalline silicon piezoresistive pressure sensors can be volume manufactured in standard IC-foundries with ultra-low fabrication cost for applications of consumer electronics. The pressure sensor sensitivity range 750KPa is about 0.033mV/V/KPa and the non-linearity is less than ±0.1%·FS. Even though the two rows of opening holes are embedded in the silicon diaphragm, the tested zero-point temperature coefficient as low as -0.022%/ °C · FS (-40°C to +120°C) indicates no obvious influence to the sensor stability.