Differential pressure sensing die

Patent metadata

Field	Value
Publication number	US-9316552-B2
Application number	US-201414193992-A
Country	US
Kind code	B2
Filing date	Feb 28, 2014
Priority date	Feb 28, 2014
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

A differential pressure sensor includes a pressure sensing die comprising a semiconductor die, having a thinned portion forming a diaphragm. The diaphragm includes piezo-resistive elements that exhibit varying resistance based on force exerted on the diaphragm. A first support structure is bonded to a first surface of the semiconductor die, having an aperture defined through the support structure such that a first surface of the diaphragm is exposed through the aperture. A second support structure is bonded to the opposite side of the semiconductor die having an aperture aligned with the opposing side of the diaphragm. Electrical components in electrical communication with the piezo-resistive elements are arranged outside the region defined by the bond between the first and second support structures and the semiconductor die. An oil-filled volume may be defined between the semiconductor die and a harsh medium which transmits a fluid pressure to the die without the harsh medium contacting the die.

First claim

What is claimed is:

1. A differential pressure sensing die for measuring the differential pressure between two isolated fluids, the differential pressure sensing die comprising:
a semiconductor die having an upper surface and a lower surface, and having a first region at a first thickness, and a second region having a second thickness, the second thickness being less than the first thickness, the second region defining a diaphragm, the diaphragm having disposed thereon, at least one piezo-resistive element, the at least one piezo-resistive element exhibiting a varying resistance responsive to deflection of said diaphragm;
a first support structure bonded to the upper surface of the semiconductor die, the first support structure having an aperture defined therethrough, the aperture adapted to expose the diaphragm through said first support structure and provide a seal with the upper surface of the first semiconductor die; and
a second support structure bonded to the lower surface of the semiconductor die, the second support structure having an aperture defined therethrough, the aperture adapted to expose the diaphragm through said second support structure.

2. The differential pressure sensing die of claim 1 , wherein said semiconductor die comprises silicon.

3. The differential pressure sensing die of claim 2 , wherein said first support structure comprises silicon.

4. The differential pressure sensing die of claim 3 , wherein said second support structure comprises silicon.

5. The differential pressure sensing die of claim 4 , wherein said first support structure is anodically bonded to a layer of polysilicon on the surface of said semiconductor die and said second support structure is anodically bonded to the exposed silicon of said semiconductor die.

6. The differential pressure sensing die of claim 2 , wherein said first support structure comprises glass.

7. The differential pressure sensing die of claim 3 , wherein said second support structure comprises glass.

8. The differential pressure sensing die of claim 4 , wherein said first support structure and said second support structure are bonded to said semiconductor die by a glass frit bond.

9. The differential pressure sensing die of claim 1 , further comprising:
an electrically conductive contact pad in electrical communication with said diaphragm, said conductive contact pad disposed on a surface of said semiconductor die in a region outside of a region defined by said diaphragm, said first support structure and said second support structure.

10. A differential pressure sensing die, comprising:
a semiconductor die having an upper surface and a lower surface, and having a first region at a first thickness, and a diaphragm having a second thickness less than the first thickness interior to the first region, the diaphragm having at least one piezo-resistive element, the at least one piezo-resistive element exhibiting a varying resistance responsive to deflection of said diaphragm;
a first support structure bonded to the upper surface of the semiconductor die, the first support structure having an aperture defined therethrough, the aperture aligned with the diaphragm; and
a second support structure bonded to the lower surface of the semiconductor die, the second support structure having an aperture defined therethrough and aligned with the diaphragm.

11. The differential pressure sensing die of claim 10 , wherein said semiconductor die is of silicon.

12. The differential pressure sensing die of claim 11 , wherein said first and second support structures are of silicon.

13. The differential pressure sensing die of claim 12 , wherein said first support structure is anodically bonded to a layer of polysilicon on the surface of said semiconductor die and said second support structure is anodically bonded to the exposed silicon of said semiconductor die.

14. The differential pressure sensing die of claim 11 , wherein said first and second support structures comprise glass.

15. The differential pressure sensing die of claim 14 , wherein said first support structure and said second support structure are bonded to said semiconductor die by a glass frit bond.

16. The differential pressure sensing die of claim 10 , further comprising:
an electrically conductive contact pad in electrical communication with said piezo-resistive element, said conductive contact pad disposed on the upper surface of said semiconductor die outward from said first support structure.

17. The differential pressure sensing die of claim 16 , wherein the electrically conductive contact pad is in electrical communication with said piezo-resistive element via one or more conductors defined in the upper surface of the semiconductor die.

Assignees

• Measurement Spec Inc

Inventors

• Wagner David E
• Hoffman James H
• Jenni Kaspar L

Classifications

• H10W72/884

  Die-attach connectors and bond wires · CPC title

• G01L9/0054 Primary

  integral with a semiconducting diaphragm · CPC title

• G01L9/0052

  of piezoresistive elements (circuits therefor G01L9/06) · CPC title

• G01L13/025 Primary

  using diaphragms · CPC title

• G01L9/0042

  Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms (details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively) · CPC title