Pressure transducer comprising a sealed transducer with a rigid diaphragm

• US 5,912,499 A
• Filed: 12/22/1995
• Issued: 06/15/1999
• Est. Priority Date: 12/28/1992
• Status: Expired due to Term

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Diem, Bernard, Delaye, Marie-Therese
• Primary Examiner(s): Saadat, Mahshid
• Assistant Examiner(s): Wilson, Allan R.
• Application Number:
  US08/579,063
• Time in Patent Office: 1,271 Days
• Field of Search: 257/415, 257/417, 257/418, 257/419, 257/420, 438/53, 438/50
• US Class Current: 257/419
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81C 1/00158 Diaphragms, membranes manufacture process for semi-permeable inorganic membranes B01D67/0039
• CPC Class Codes: G01L 9/0042 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 Class Codes: G01L 9/0055 bonded on a diaphragm
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm
• CPC Class Codes: Y10S 148/135 Removal of substrate
• CPC Class Codes: Y10S 148/159 Strain gauges

Abstract

An integrated pressure sensitive transducer incorporating a pressure sensitive structure having a silicon substrate, and at least one monocrystalline silicon diaphragm deformable in a direction perpendicular to the substrate. The diaphragm, which is joined to the substrate at its periphery by means of an etched insulating layer, has a centered insulating stud which bears on the substrate in order to increase the rigidity of the diaphragm. Completing the transducer and for measuring the deformation of the diaphragm is at least one first electrode located in the substrate facing a high deformation region of the diaphragm and remote from the periphery of the diaphragm and the insulating stud, and at least one second electrode facing at least one low deformation region of the diaphragm and in the vicinity of the periphery and/or the insulating stud.

Claims

1. An integrated pressure transducer comprising a pressure sensitive structure having a silicon substrate, at least one monocrystalline silicon diaphragm deformable in a direction perpendicular to the substrate, and means for measuring deformations of the diaphragm, said diaphragm being joined to the substrate at its periphery by means of an etched insulating layer, wherein the diaphragm has a substantially centered insulating stud for bearing on the substrate for increasing rigidity of the diaphragm, said transducer further comprising a thermal drift-free reference structure having at least one monocrystalline silicon diaphragm joined to the substrate and made rigid by several insulating studs distributed over its entire surface and bearing on the substrate, and electric contacts formed on said rigid diaphragm.

2. A transducer according to claim 1, wherein the measuring means comprises at least one capacitor, and the silicon film and the substrate are conductive and together form plates of the capacitor.

3. A transducer according to claim 2, further comprising at least one buried electrode in the substrate facing the deformable diaphragm.

4. A transducer according to claim 1, further comprising a buried reference electrode in the substrate facing the rigid diaphragm.

5. A transducer according to claim 2, further comprising at least one first electrode located in the substrate facing a high deformation region of the diaphragm and remote from the periphery of the diaphragm and the insulating stud, and at least one second electrode facing at least one relatively low deformation region of the diaphragm in vicinity of the periphery and the insulating stud.

6. A transducer according to claim 2, comprising at least one first electrode located in the substrate facing said diaphragm in a first deformable region of the diaphragm and remote from the periphery of the diaphragm and the insulating stud, and at least one second electrode facing said diaphragm in at least one second deformable region of the diaphragm in vicinity of the insulting stud.

7. A transducer according to claim 1, wherein the diaphragm is circular in plan.

8. An integrated pressure transducer comprising a pressure sensitive structure having a silicon substrate, at least one monocrystalline silicon diaphragm deformable in a direction perpendicular to the substrate, and means for measuring deformations of the diaphragm, said diaphragm being joined to the substrate at its periphery by means of an etched insulating layer, wherein the diaphragm has a substantially centered insulating stud for bearing on the substrate for increasing rigidity of the diaphragm, and wherein the means for measuring deformation of the diaphragm comprises at least one first electrode located in the substrate facing said diaphragm in a first deformable region of the diaphragm and remote from the periphery of the diaphragm and the insulating stud, and at least one reference electrode facing the same diaphragm in at least a second deformable region of the diaphragm in vicinity of the periphery;

said second deformable region being more rigid than said first deformable region.

9. A transducer according to claim 8, wherein the diaphragm is circular in plan.

10. A transducer according to claim 8, wherein the measuring means has at least one capacitor, and the silicon film and substrate are conductive and together form plates of the capacitor.

11. A transducer according to claim 8, also comprising at least one buried electrode in the substrate facing the deformable diaphragm.

12. A transducer according to claim 8, further comprising a reference structure having at least one monocrystalline silicon diaphragm joined to the substrate and made rigid by several insulating studs distributed over its entire surface and bearing on the substrate, electric contacts being formed on said rigid diaphragm.

13. A transducer according to claim 12, further comprising a buried reference electrode in the substrate facing the rigid diaphragm.

14. An integrated pressure transducer comprising a pressure sensitive structure having a silicon substrate, at least one monocrystalline silicon diaphragm deformable in a direction perpendicular to the substrate, and means for measuring deformations of the diaphragm, said diaphragm being joined to the substrate at its periphery by means of an etched insulating layer, where the diaphragm has a substantially centered insulating stud for bearing on the substrate for increasing rigidity of the diaphragm, and wherein the means for measuring deformation of the diaphragm comprises at least one first electrode located in the substrate facing said diaphragm in a first deformable region of the diaphragm and remote from the periphery of the diaphragm and the insulating stud, and at least one second electrode facing the same diaphragm in at least a second deformable region of the diaphragm in vicinity of the periphery and the insulating stud;

said second deformable region being more rigid than said first deformable region.

15. A transducer according to claim 14, wherein the diaphragm is circular in plan.

16. A transducer according to claim 14, wherein the measuring means has at least one capacitor, and the silicon film and the substrate are conductive and together form plates of the capacitor.

17. A transducer according to claim 14 further comprising at least one buried electrode in the substrate facing the deformable diaphragm.

18. A transducer according to claim 14, further comprising a reference structure having at least one monocrystalline silicon diaphragm joined to the substrate and made rigid by several insulating studs distributed over its entire surface and bearing on the substrate, electric contacts being formed on said rigid diaphragm.

19. A transducer according to claim 18, also comprising a buried reference electrode in the substrate facing the rigid diaphragm.

20. An integrated pressure transducer comprising a pressure sensitive structure having a silicon substrate, at least one monocrystalline silicon diaphragm deformable in a direction perpendicular to the substrate, and means for measuring deformations of the diaphragm, said diaphragm being joined to the substrate at its periphery by means of an etched insulating layer, wherein the diaphragm has a substantially centered insulating stud for bearing on the substrate for increasing rigidity of the diaphragm, and wherein the means for measuring deformation of the diaphragm comprises at least one first electrode located in the substrate facing said diaphragm in a first deformable region of the diaphragm and remote from the periphery of the diaphragm and the insulating stud, and at least one reference electrode facing the same diaphragm in at least a second deformable region of the diaphragm in vicinity of the insulating stud;

said second deformable region being more rigid than said first deformable region.

21. A transducer according to claim 20, wherein the diaphragm is circular in plan.

22. A transducer according to claim 20, wherein the measuring means has at least one capacitor, and the silicon film and the substrate are conductive and form plates of the capacitor.

23. A transducer according to claim 20, also comprising at least one buried electrode in the substrate facing the deformable diaphragm.

24. A transducer according to claim 20, further comprising a reference structure having at least one monocrystalline silicon diaphragm joined to the substrate and made rigid by several insulating studs distributed over its entire surface and bearing on the substrate, electric contacts being formed on said rigid diaphragm.

25. A transducer according to claim 24, also comprising a buried reference electrode in the substrate facing the rigid diaphragm.