Patent ID: 9546922
Date: 2017-01-17
CPC Classifications: G01L

Claim:
1. A pressure sensor comprising: a top cap; a recess formed in an end of the top cap; a cavity formed in the end of the top cap and communicating with the recess such that the cavity extends further axially into the top cap than the recess thereby having depth greater than a depth of the recess, outer edges of the recess extend laterally outward beyond outer edges of the cavity thereby defining a bonding boundary; and a silicon substrate having a sensing circuit associated with a top side thereof, the top cap being bonded to the top side of the silicon substrate in a range from the outer edges of the top cap to the bonding boundary; wherein the recess and the cavity of the top cap face the top side of the silicon substrate and form a reference vacuum cavity and wherein, when pressure is exerted on a backside of the substrate, a portion of the silicon substrate is constructed and arranged to deflect, wherein the portion of the silicon substrate comprises a diaphragm and at least a portion of the sensing circuit is associated with the top side of the diaphragm and in opposing relation with respect to the cavity, and wherein the to cap includes a portion within the cavity that is axially aligned with a center of the diaphragm and which defines a surface of the recess so as to constrain deformation of the diaphragm.