US Patent 7713771 Pressure sensor

A differential pressure sensor includes a micro-electromechanical sensor die fabricated as a plurality of sensor die sites on a semiconductor wafer, and then singularized, the sensor die having a top face surface including die electrical output pads exposed to a first test fluid source and a bottom side surface exposed to a second test fluid source. The differential pressure further has a sensor die support member having a die support member fluid access port with a support member port perimeter; wherein one of the top face surface or the bottom side surface is sealed fully around the support member port perimeter by a wafer scale seal formed on the plurality of sensor die sites before die singulation. Wafer scale seals may be formed by a photofabrication process, screen printing, stamp printing, or pressure transfer printing. Some embodiments may include a photofabricated seal formed by a photosensitive polydimethylsiloxane material, by a filled photofabricated mold, and by photopatterned glass frit.