Sensor package assembly having an unconstrained sense die

• US 8,322,225 B2
• Filed: 06/30/2010
• Issued: 12/04/2012
• Est. Priority Date: 07/10/2009
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Bentley, Ian, Bradley, Alistair David, Cook, Jim
• Primary Examiner(s): THOMPSON, JEWEL VERGIE
• Application Number:
  US12/828,155
• Publication Number:
  US 20110005326A1
• Time in Patent Office: 888 Days
• Field of Search: 737/291, 737/06, 737/54, 737/26
• US Class Current: 73/754
• CPC Class Codes: G01L 19/148 Details about the circuit board integration, e.g. integrated with the diaphragm surface or encapsulation
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/10158 at the passive surface
• CPC Class Codes: H01L 2924/1461 MEMS
• CPC Class Codes: H01L 2924/15151 the die mounting substrate comprising an aperture, e.g. for underfilling, outgassing, window type wire connections

Abstract

A pressure detection mechanism having a pressure sense die which may be attached directly to a surface of an alumina-based substrate with an adhesive having an optimum thickness. The adhesive may be stress compliant and may be one or more of silicone, silicone-epoxy, epoxy or any other suitable adhesive material. A compensation and interface application specific integrated circuit may be attached to the surface of the package substrate. The pressure sense die may be electrically connected to the integrated circuit with bond wires. The integrated circuit may be electrically connected to trace conductors on the package substrate with bond wires, and trace conductors may be connected to stress compliant metal conductors or leads for external connection to a mounting surface such as a printed circuit board. Hard plastic, or like material, symmetric covers, with one or more pressure ports or vents, may be attached to both sides of the substrate.

Claims

1. A pressure sensor comprising:

a package substrate;

a pressure sense die directly attached to a first side of the package substrate with a stress compliant adhesive;

an application specific integrated circuit electrically connected to the sense die and attached to the first side of the package substrate;

a cover mounted over the first side of the substrate; and

a wire bonding for electrically connecting the pressure sense die to the application specific integrated circuit;

wherein the package substrate has an area-to-thickness ratio less than 100 square units per lineal unit.

2. A pressure detection mechanism comprising:

a package substrate;

a pressure sense die directly attached to a first side of the package substrate with a stress compliant adhesive;

an application specific integrated circuit electrically connected to the sense die and attached to the first side of the package substrate;

a first cover mounted over the first side of the substrate; and

a second cover mounted over a second side of the substrate.

3. The mechanism of claim 2, further comprising:

stress compliant metal leads attached to the package substrate;

trace conductors on the first side of the package substrate electrically connected to the metal leads;

a first wire bonding for electrically connecting the pressure sense die to the application specific integrated circuit; and

a second wire bonding for electrically connecting the application specific integrated circuit to a trace conductor.

4. The mechanism of claim 2, wherein the stress compliant adhesive includes one or more of a silicone material, a silicone-epoxy material and an epoxy material.

5. The mechanism of claim 2, wherein the package substrate comprises an alumina ceramic material.

6. The mechanism of claim 2, wherein the first and second covers have the same footprints along the package substrate.

7. The mechanism of claim 6, wherein the first and second covers are symmetric in shape and size with an exception of a pressure port or vent on at least one of the covers.

8. The mechanism of claim 2, wherein the covers are fabricated from a polyamide material.

9. The mechanism of claim 2, wherein the first and second covers are mounted on the first and second sides, respectively, of the substrate with a stress compliant adhesive.

10. The mechanism of claim 2, wherein:

the application specific integrated circuit is a compensation circuit for the pressure sense die; and

the application specific integrated circuit is attached to the package substrate with a stress compliant adhesive.

11. The mechanism of claim 2, wherein the adhesive between the pressure sense die and the package substrate has an optimum thickness.

12. The mechanism of claim 2, wherein the package substrate has an area-to-thickness ratio less than 100 square units per linear unit.

13. The mechanism of claim 2, wherein the pressure sense die comprises one or more Wheatstone bridge piezoresistive stress sensing elements.

14. The mechanism of claim 2, wherein the stress compliant adhesive is the only item between the pressure sense die and the package substrate.

15. The mechanisms of claim 2, wherein the pressure sense die is a silicon MEMS device.

16. The mechanism of claim 2, wherein the package substrate is contained in a package selected from a group consisting of dual-in-line packages, single-in-packages and surface mount packages.

17. The mechanism of claim 2, wherein the package substrate has a hole in an area that corresponds to a diaphragm of the pressure sense die.

18. The mechanism of claim 2, wherein the pressure sense die is bonded directly to the package substrate.

19. A pressure detection mechanism comprising:

a package substrate; and

a pressure sense die attached to a first side of the package substrate; and

wherein the pressure sense die is attached directly to the first side of package substrate with a stress compliant adhesive.

20. The mechanism of claim 19, wherein:

the stress compliant adhesive comprises a silicone material; and

the package substrate comprises an alumina-based material.

21. A pressure detection mechanism comprising:

an alumina-based substrate; and

a pressure sense die attached to a package substrate with a stress compliant adhesive; and

wherein no isolation substrate or layer is situated between the pressure sense die and the package substrate.