Pressure sensor and method of fabrication thereof
First Claim
1. A process for fabricating a pressure sensor comprising the steps of:
- disposing a pressure sensing element within a first chamber within a portion of a package of said sensor;
disposing a signal processing element within a second chamber within said package portion;
electrically interconnecting said two elements;
leaving said second chamber and the signal processing element therein hermetically unenclosed while hermetically enclosing said first chamber and exposing said sensing element to apparatus which generates a known test pressure;
adjusting electrical parameters of the signal processing element in accordance with said known test pressure being applied to the pressure sensing element;
removing said known pressure; and
sealing an enclosing member to said package portion for hermetically sealing at least said first chamber from the ambient while providing a port which provides access to said first chamber.
1 Assignment
0 Petitions
Accused Products
Abstract
A pressure sensor includes a three part package including a housing member defining two spaced-apart chambers, a bottom member providing the bottom wall of one of the chambers, and a top cover member hermetically sealing the two chambers from one another and including a port for admission of gases into one of the chambers. A pressure sensing element is disposed in the chamber having the port and mounted on the bottom member, and a signal processing element is mounted in the other chamber. Electrical connections between the two elements are by means of leads which extend into each chamber and pass through a wall separating the chambers. A low temperature differential between the two elements is provided by extending one of the leads from the other one chamber to a position directly underlying and in intimate contact with the bottom surface of the processing element in the other chamber. Additionally, the bottom member is of a high thermal conductivity material and extends along the bottom of the housing member to beneath the other chamber.
120 Citations
18 Claims
-
1. A process for fabricating a pressure sensor comprising the steps of:
-
disposing a pressure sensing element within a first chamber within a portion of a package of said sensor; disposing a signal processing element within a second chamber within said package portion; electrically interconnecting said two elements; leaving said second chamber and the signal processing element therein hermetically unenclosed while hermetically enclosing said first chamber and exposing said sensing element to apparatus which generates a known test pressure; adjusting electrical parameters of the signal processing element in accordance with said known test pressure being applied to the pressure sensing element; removing said known pressure; and sealing an enclosing member to said package portion for hermetically sealing at least said first chamber from the ambient while providing a port which provides access to said first chamber.
-
-
2. A process for fabricating a pressure sensor comprising the steps of:
-
disposing a pressure sensing element within a first chamber within a portion of a package of said sensor; disposing a signal processing element within a second chamber within said package portion; electrically interconnecting said two elements; leaving said second chamber and the signal processing element therein exposed to ambient pressure and exposed for adjustment while hermetically enclosing said first chamber and exposing said sensing element to a known test pressure; measuring electrical parameters of the signal processing element while applying the known test pressure to the pressure sensing element; laser trimming selected portions of the circuitry on the signal processing element consistent with the known test pressure to provide desired adjustments; removing the test pressure from the sensing element; and sealing an enclosing member to said package portion for hermetically sealing at least said first chamber from the ambient while providing a port which provides access to said first chamber.
-
-
3. A pressure sensor comprising:
-
a package comprising a housing member having integral therewith an outside wall and an interior wall which define two chambers separated from each other by the interior wall; a pressure sensing element disposed in a first of said chambers, and a signal processing element disposed in a second of said chambers; a plurality of conductive leads extending through said interior wall and being exposed within each of said chambers; at least one of said leads having an enlarged portion that is in thermal contact with a substantial portion of the signal processing element; bonding wires electrically interconnecting said two elements to said conductive leads; a second wall in said housing member, spaced from said interior wall and extending up into said second chamber, and other walls in said second chamber defining a recess within said second chamber for receiving said signal processing element; inwardly sloped side walls on said recess that provide guide means for proper positioning of said signal processing element in said second chamber; a cover member on said housing member hermetically sealing said first chamber; a port in the cover member coupled to said first chamber for connection of said first chamber to a pressure to be sensed. - View Dependent Claims (4, 5, 6, 7)
-
-
8. A process for fabricating a pressure sensor comprising the steps of:
-
disposing a pressure sensing element within a first chamber within a portion of a package of said sensor; disposing a signal processing element within a second chamber within said package portion; electrically interconnecting said two elements; leaving said second chamber and the signal processing element therein unenclosed while hermetically enclosing said first chamber and exposing said sensing element to apparatus which generates a preselected test pressure; contacting the signal processing element for adjusting the electrical parameters thereof in accordance with the test pressure; removing the test pressure; and sealing an enclosing member to said package portion for hermetically sealing said two chambers from one another while providing a port which provides access to said first chamber. - View Dependent Claims (9)
-
-
10. A process for forming a pressure sensor assembly having first and second chambers with electrical leads communicating between chambers comprising the steps of:
-
sealing bottom and side portions of the electrical leads so as to hermetically isolate the chambers from each other where the leads pass from one chamber to the other; attaching a back cover to a body portion of the pressure sensor assembly and forming a hermetic seal at the intersection of the back cover and the body portion; disposing a pressure sensor element within the first chamber and disposing a signal processing element in the second chamber; electrically coupling each of the elements to the electrical leads; coating a portion of the pressure sensor element and coating top and side portions of the portions of the electrical leads in the first chamber with a passivating material; hermetically enclosing the first chamber and exposing the sensing element to a preselected test pressure while leaving the second chamber and the processing element therein unenclosed; sensing signals from the processing element and adjusting portions of the processing element such that signals received therefrom correspond to the applied test pressure; removing the test pressure from the first chamber; coating a portion of the processing element and top and side portions of the portions of the electrical leads in the second chamber; and attaching a top cover to the body of the sensor for hermetically sealing the first chamber and thus hermetically isolating the first chamber from the second chamber, said top cover defining a port which provides access to the first chamber.
-
-
11. A pressure sensor comprising:
-
a package comprising a housing member having integral therewith an outside wall and an interior wall which define two chambers separated from each other by the interior wall; a pressure sensing element disposed in a first of said chambers, and a signal processing element disposed in a second of said chambers; a plurality of conductive leads extending through said interior wall and being exposed within each of said chambers; at least one of said conductive leads having an enlarged portion that is in thermal contact with a substantial portion of the signal processing element; means for electrically interconnecting said two elements to said leads; a second wall in said housing, spaced from said interior wall and extending up from the bottom of said second chamber, for defining a recess within said second chamber for receipt of said signal processing element; inwardly sloped side walls on said recess that provide guide means for proper positioning of said signal processing element therein; a cover member on the housing hermetically sealing said first chamber; and a port on the cover member for coupling the first chamber to a pressure to be sensed. - View Dependent Claims (12, 13)
-
-
14. A pressure sensor comprising:
-
a package comprising a housing member having integral therewith an outside wall and an interior wall which define two chambers separated from each other by the interior wall; a pressure sensing element disposed in a first of said chambers, an integral bottom wall partially across a second of said chambers; a signal processing element supported by said bottom wall of said second chamber; a plurality of electrically conductive leads extending through said interior wall and being exposed within each of said chambers; bonding wires electrically interconnecting said two elements with said conductive leads; at least one of said leads having an enlarged portion that provides thermally conductive bottom wall portion for said second chamber; said signal processing element supported on said thermally conductive bottom wall portion in intimate thermal contact therewith; a closure member of a material having a higher thermal conductivity than that of material forming said housing, said closure member forming a bottom wall of said first chamber and extending beneath said interior wall to a position underlying said second chamber, effective to form a high thermal conductivity path for heat transfer from said first chamber to said processing element; a cover member on the housing hermetically sealing said first chamber; a port in said cover coupled to said first chamber for connection of said first chamber to a pressure to be sensed.
-
-
15. A pressure sensor comprising:
-
a package comprising a housing member having integral therewith an outside wall and an interior wall which define two chambers separated from each other by the interior wall; a pressure sensing element disposed in a first of said chambers and a signal processing element disposed in a second of said chambers; a plurality of electrical conductive leads extending through said interior wall and being exposed within each of said chambers; at least one of said leads having an enlarged portion that provides a thermally conductive bottom wall portion for said second chamber; said signal processing element supported on said thermally conductive bottom wall portion in thermal contact therewith; means for electrically interconnecting said two elements to said conductive leads; a lip completely around said first chamber upper end that forms a cylinder which projects beyond the upper surface of adjacent portions of the housing member, effective to form an annular surface around said first chamber that can be selectively hermetically sealed; a cover member on the housing hermetically sealing said first chamber; a port in said cover coupled to said first chamber for connection of said first chamber to a pressure to be sensed. - View Dependent Claims (16, 17, 18)
-
Specification