High over-pressure capable silicon die pressure sensor

• US 10,060,813 B2
• Filed: 09/27/2016
• Issued: 08/28/2018
• Est. Priority Date: 09/29/2015
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Willcox, Charles R., Meyer, Nicholas E.
• Primary Examiner(s): ALLEN, ANDRE J
• Application Number:
  US15/277,161
• Publication Number:
  US 20170089787A1
• Time in Patent Office: 700 Days
• Field of Search: None
• CPC Class Codes: G01L 19/0618 Overload protection
• CPC Class Codes: G01L 9/0047 Diaphragm with non uniform thickness, e.g. with grooves, bosses or continuously varying thickness

Abstract

A sensor includes a diaphragm having a bonding portion and a main boss separated from the bonding portion by at least one channel, the main boss having a first side face, a second side face and a chamfered corner face connecting the first side face to the second side face. A base of the sensor has a first contact area aligned with the main boss and separated from the main boss, wherein the bonding portion of the diaphragm is bonded to the base. At least one sensing element senses movement of the diaphragm.

Claims

1. A sensor comprising:

a diaphragm having a bonding portion and a main boss separated from the bonding portion by at least one channel, the main boss having a first side face, a second side face and a chamfered corner face connecting the first side face to the second side face;

a base having a first contact area aligned with the main boss and separated from the main boss, wherein the bonding portion of the diaphragm is bonded to the base; and

at least one sensing element that senses movement of the diaphragm.

2. The sensor of claim 1 wherein the main boss further comprises a third side face and a fourth side face and a second chamfered corner face between the second side face and the third side face, a third chamfered corner face between the third side face and the fourth side face and a fourth chamfered corner face between the fourth side face and the first side face.

3. The sensor of claim 1 further comprising a secondary boss separated from the first side face of the main boss by a channel, the secondary boss having a first side surface, an end surface, and a first chamfered corner surface between the first side surface and the end surface.

4. The sensor of claim 3 further comprising a second secondary boss separated from the second side face of the main boss by a second channel, a third secondary boss separated from the third side face of the main boss by a third channel, and a fourth secondary boss separated from the fourth side face of the main boss by a fourth channel.

5. The sensor of claim 4 wherein a length of the main boss is the same as a length of the secondary boss.

6. The sensor of claim 4 further comprising a first pyramid boss located at an intersection of a line through the secondary boss and a line through the second secondary boss.

7. The sensor of claim 6 wherein the pyramid boss has a base edge that is at forty-five degrees to the line through the secondary boss.

8. The sensor of claim 6 wherein the base further comprises a contact bar mesa aligned with and separated from the secondary boss and a contact pyramid mesa aligned with and separated from the first pyramid boss such that above a pressure threshold, the main boss contacts the first contact area while nearly simultaneously the secondary boss contacts the contact bar mesa and the first pyramid boss contacts the contact pyramid mesa.

9. The sensor of claim 1 wherein the main boss has rounded boss edges.

10. A pressure sensor comprising:

a base;

a diaphragm positioned over the base and having at least one boss with a chamfered corner; and

a sensing element positioned to sense changes in the diaphragm.

11. The pressure sensor of claim 10 wherein the at least one boss comprises a main boss centrally located on the diaphragm.

12. The pressure sensor of claim 11 further comprising at least one secondary boss positioned on a side of the main boss and having at least one chamfered corner.

13. The pressure sensor of claim 10 further comprising a pyramid boss positioned such that the chamfered corner of the main boss faces the pyramid boss.

14. The pressure sensor of claim 13 wherein the pyramid boss has a square base such that one edge of the square base is parallel to an edge of the chamfered corner.

15. The pressure sensor of claim 12 further comprising a pyramid boss positioned such that the chamfered corner of the main boss faces the pyramid boss.

16. The pressure sensor of claim 10 wherein the boss has rounded edges formed through dry isotropic etching.

17. A pressure sensor comprising:

a base;

a diaphragm comprising a main boss with two edges and a corner between the two edges and a pyramid boss positioned proximate the corner of the main boss and having a base with an edge that is oblique to both of the two edges of the main boss; and

a sensing element that senses movement of the diaphragm.

18. The pressure sensor of claim 17 wherein corner between the two edges of the main boss is chamfered.

19. The pressure sensor of claim 18 wherein the chamfered corner of the main boss has an edge that is parallel to the edge of the pyramid boss.

20. The pressure sensor of claim 17 further comprising a secondary boss having a base with an edge that is parallel to one of the two edges of the main boss.

21. The pressure sensor of claim 17 wherein the secondary boss comprises at least one chamfered corner.