Patent ID: 6928879

Claim:
A method for making a pressure sensor, comprising: providing a wafer including at least a base silicon layer, a buried sacrificial layer, and a top silicon layer, the top silicon layer arranged over the buried sacrificial layer, the buried sacrificial layer arranged over the base silicon layer; etching at least one vent through the top silicon layer to the buried sacrificial layer; removing at least a portion of the buried sacrificial layer to form a cavity; depositing a sealing silicon bearing compound to seal the at least one vent; and arranging a sensing element on the wafer; wherein the etching of the at least one vent includes etching at least one tapered vent, the at least one tapered vent having a first cross section towards a top of the top silicon layer and a second cross section towards the buried sacrificial layer, a first width of the first cross section being greater than a second width of the second cross section, the first width being parallel to the second width.