Pressurer sensor and method for assembly of same

A pressure sensor comprising:

• a substrate of alumina having oppositely disposed first and second surfaces, and having thick film signal conditioning circuitry on said first surface, said thick film circuitry on said first surface containing at least one resistor characterized by a resistance value which can be varied in response to a signal output by said signal conditioning circuitry;
• a silicon pressure sensing integrated circuit disposed on said second surface of said substrate, said pressure sensing integrated circuit having a semiconductor circuit means including a pressure sensitive element and associated circuitry for producing a pressure sensitive output signal;
• at least one electrically conductive through-hole for contact with and electrical connection of said thick film signal conditioning circuitry on said first surface and said associated circuitry on said second surface, all of said at least one through-holes being located adjacent the perimeter of said substrate;
• a ported housing having a circumferential ledge, said second surface of said substrate being mounted to said circumferential ledge of said ported housing so as to form a pressurized chamber enclosing said silicon pressure sensing integrated circuit and so as to seal all of said at least one through-holes located adjacent the perimeter of said substrate;
• and
• a cover for enclosing said top surface of said substrate, wherein prior to enclosing said top surface, said resistance value of said at least one resistor disposed on said first surface of said substrate is adjusted in response to said signal output of said signal conditioning circuitry.

A method for manufacturing a pressure sensor comprising the following steps:

• providing a substrate of alumina having a first and second surface, said alumina substrate having a thick film signal conditioning circuit including at least one resistor of varying resistance value disposed on said first surface, and said substrate having a silicon pressure sensing integrated circuit disposed on said second surface, said pressure sensing integrated circuit having a semiconductor circuit means including a pressure sensitive element and associated circuitry for producing a pressure sensitive output signal, said substrate further having at least one electrically conductive through-hole for electrically interconnecting said circuits on said first and second surfaces, all of said at least one electrically conductive through-holes are located adjacent the perimeter of said substrate;
• enclosing said first surface of said substrate with a ported housing so as to form a pressurized chamber, wherein said step of enclosing concurrently seals all of said at least one electrically conductive through-holes;
• pressurizing said pressurized chamber such that said pressure sensitive integrated circuit and said signal conditioning circuitry respond to form an output signal;
• adjusting said resistance value of said at least one resistor disposed on said first surface in response to said output signal;
• and
• enclosing said first surface of said substrate after said adjusting step so as to form an air-tight, operable pressure sensor.