APPARATUS AND METHOD FOR SENSING INTRAVASCULAR PRESSURE

摘要

A pressure sensor assembly (11) is provided for placement within the tip of a conventional catheter (15) or the like for insertion into a small cavity such as a human coronary artery. The pressure sensor assembly (11) is comprised of device and backing dies (67 and 75) of crystalline material bonded together without the use of a bonding material, thereby providing direct contact between the two crystalline dies. A diaphragm (25) is etched into one of the dies before it is bonded to the other die. A cavity (26) formed by the diaphragm when the two dies are bonded is vented to a reference atmosphere by a channel or groove (31) in the backing die. During the fabrication of the sensor assembly, small holes (71) are etched completely through the wafer (75) used to form the device dies in order to provide targets for alignment during the fabrication of the sensor assembly. Finally, the fabrication of circuitry on the wafer forming the device dies includes providing complementary temperature coefficients of the nominal piezoresistance and of the piezoresistive coefficient.