Implantable capacitive pressure sensor apparatus and methods regarding same

• US 8,424,388 B2
• Filed: 01/28/2011
• Issued: 04/23/2013
• Est. Priority Date: 01/28/2011
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Mattes, Michael F., Ruben, David A.
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): JENKINS, JERMAINE L
• Application Number:
  US13/016,363
• Publication Number:
  US 20120197155A1
• Time in Patent Office: 816 Days
• Field of Search: None
• US Class Current: 73/700
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/028 Microscale sensors, e.g. electromechanical sensors [MEMS]
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: G01L 9/0072 using variations in capacitance
• CPC Class Codes: G01L 9/12 by making use of variations in capacitance , i.e. electric circuits therefor
• CPC Class Codes: H01L 2224/32145 the bodies being stacked
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48145 the bodies being stacked
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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

Abstract

An implantable capacitive pressure sensor apparatus and method for making such an apparatus includes a first pressure sensor portion and a second pressure sensor portion. The first pressure sensor portion includes a diaphragm electrode connectable to ground (e.g., the diaphragm electrode being positioned in close proximity to the body when implanted therein such that the diaphragm electrode is deformable in response to pressure applied thereto by the body). The second pressure sensor portion includes a signal electrode (e.g., wherein the first pressure sensor portion and the second pressure sensor portion are coupled such that a gap is provided between the diaphragm electrode and the signal electrode) and an insulator material. The signal electrode is provided on and in direct contact with the insulator material to electrically isolate the signal electrode such that parasitic capacitance effects on the signal electrode are reduced.

Claims

1. An implantable capacitive pressure sensor apparatus, comprising:

a first pressure sensor portion comprising a diaphragm electrode connectable to ground, wherein the diaphragm electrode is positioned in close proximity to the body when implanted therein such that the diaphragm electrode is deformable in response to pressure applied thereto by the body; and

a second pressure sensor portion comprising;

a signal electrode, wherein the first pressure sensor portion and the second pressure sensor portion provide a gap between the diaphragm electrode and the signal electrode, and

an insulator material, wherein the signal electrode is provided on and in direct contact with the insulator material to electrically isolate the signal electrode such that parasitic capacitance effects on the signal electrode caused by electrical activity in the body when the pressure sensor apparatus is implanted therein are reduced, and further wherein the diaphragm electrode is grounded when the implantable pressure sensor apparatus is implanted in the body to shield the signal electrode from electrical activity in the body.

2. The apparatus of claim 1, wherein the second pressure sensor portion comprises a glass substrate material extending from a first side surface to a second side surface opposite the first side surface, and further wherein the signal electrode is provided on and in direct contact with the first side surface of the glass substrate material.

3. The apparatus of claim 2, wherein the signal electrode is provided on and in direct contact with the glass substrate material and electrically connected to one or more die of the pressure sensor apparatus via conductive material patterned on at least a portion of the glass substrate material.

4. The apparatus of claim 2, wherein one or more openings are defined through the glass substrate material, and further wherein the signal electrode is provided on and in direct contact with the glass substrate material and electrically connected to one or more die of the pressure sensor apparatus via conductive material formed in the one or more openings.

5. The apparatus of claim 1, wherein the diaphragm electrode of the first pressure sensor portion lies parallel to the signal electrode of the second pressure sensor portion along an axis of a gap capacitor formed thereby, wherein the diaphragm electrode is deformable over a cross-sectional area orthogonal to the axis, and further wherein the signal electrode provided on and in direct contact with the insulator material has a cross-sectional area orthogonal to the axis that is about the same as, or no more than 95 percent smaller than, the deformable cross-sectional area of the diaphragm electrode orthogonal to the axis.

6. The apparatus of claim 1, wherein the signal electrode is provided on and in direct contact with the insulator material of the second pressure sensor portion to electrically isolate the signal electrode such that parasitic capacitance effects on the signal electrode caused by electrical activity in the body when the pressure sensor apparatus is implanted therein are less than 0.5 times a capacitance of a gap capacitor formed by the diaphragm electrode separated from the signal electrode by the gap.

7. The apparatus of claim 1, wherein the insulator material comprises a glass insulator material, wherein the diaphragm electrode is separated from the signal electrode by a gap distance, and further wherein the glass insulator material has a thickness adjacent the signal electrode that is greater than about 6 times the gap distance separating the diaphragm electrode from the signal electrode.

8. The apparatus of claim 1, wherein the second pressure sensor portion comprises a substrate material comprising at least one trench formed through at least a portion thereof, wherein the at least one trench is filled with the insulator material, and further wherein the signal electrode is provided on and in direct contact with the insulator material.

9. The apparatus of claim 8, wherein the second pressure sensor portion comprises a silicon substrate comprising at least one trench formed therein, wherein the at least one trench is filled with a glass insulator material, and further wherein the signal electrode is provided on and in direct contact with the glass insulator material.

10. The apparatus of claim 8, wherein the at least one trench is formed through an entire thickness thereof, wherein the at least one trench is filled with the insulator material, and further wherein the signal electrode is provided on and in direct contact with the insulator material.

11. The apparatus of claim 10, wherein the second pressure sensor portion comprises a silicon substrate comprising at least one trench formed therein, wherein the at least one trench is filled with a glass insulator material, and further wherein the signal electrode is provided on and in direct contact with the glass insulator material.

12. The apparatus of claim 1, wherein the first pressure sensor portion is bonded to the second pressure sensor portion such that a gap is provided between the diaphragm electrode and the signal electrode.

13. The apparatus of claim 12, wherein the first pressure sensor portion is bonded to the second pressure sensor portion such that at least one die cavity is provided between the first pressure sensor portion and the second pressure sensor portion, wherein one or more metallization connections are provided between the signal electrode and the die cavity for connection of the signal electrode to one or more die positioned in the die cavity, and further wherein the insulator material electrically isolates the one or more metallization connections such that parasitic capacitance effects on the one or more metallization connections caused by electrical activity in the body when the pressure sensor apparatus is implanted therein are reduced.

14. The apparatus of claim 1, wherein the implantable pressure sensor apparatus is provided as part of an implantable medical electrical lead.

15. The apparatus of claim 1, wherein the implantable pressure sensor apparatus is a wireless implantable pressure sensor apparatus.

16. The apparatus of claim 1, wherein the apparatus further comprises a third pressure sensor portion, wherein the second pressure sensor portion is bonded to the third pressure sensor portion such that at least one die cavity is provided between the second pressure sensor portion and the third pressure sensor portion, wherein one or more metallization connections are provided between the signal electrode and the die cavity for connection of the signal electrode to one or more die positioned in the die cavity.

17. The apparatus of claim 16, wherein a power source is positioned in the at least one die cavity, and further wherein the one or more die positioned in the at least one die cavity are connected such that signals can be transmitted wirelessly from the implantable pressure sensor apparatus.

18. The apparatus of claim 1, wherein the first pressure sensor portion comprises a substrate material, wherein the substrate material provides a recess formed therein to provide at least a part of the gap between the diaphragm electrode and the signal electrode.

19. The apparatus of claim 18, wherein the first pressure sensor portion comprises a silicon substrate material, wherein the silicon substrate material provides a recess formed therein to provide at least a part of the gap between the diaphragm electrode and the signal electrode, and further wherein the second pressure sensor portion comprises a planar glass substrate on which the signal electrode is directly provided.

20. The apparatus of claim 1, wherein second pressure sensor portion comprises a substrate material, wherein the substrate material provides a cavity formed therein to provide at least a part of the gap between the diaphragm electrode and the signal electrode.

21. The apparatus of claim 20, wherein second pressure sensor portion comprises a glass substrate material, wherein the glass substrate material provides a cavity defined therein to provide at least a part of the gap between the diaphragm electrode and the signal electrode.

22. The apparatus of claim 1, wherein at least one of the first and second pressure sensor portions comprise one or more patterned layers formed on a substrate material defining at least one opening to provide at least a part of the gap between the diaphragm electrode and the signal electrode.

23. A method of making an implantable capacitive pressure sensor apparatus, the method comprising:

providing a first pressure sensor portion comprising a diaphragm electrode connectable to ground, wherein the diaphragm electrode is positioned in close proximity to the body when implanted therein such that the diaphragm is deformable in response to pressure applied thereto by the body; and

providing a second pressure sensor portion comprising a signal electrode relative to the first pressure sensor portion to provide a gap between the diaphragm electrode and the signal electrode, wherein the second pressure sensor portion further comprises an insulator material, wherein the signal electrode is provided on and in direct contact with the insulator material to electrically isolate the signal electrode such that parasitic capacitance effects on the signal electrode caused by electrical activity in the body when the pressure sensor apparatus is implanted therein are reduced, and further wherein the diaphragm electrode is grounded when the implantable pressure sensor apparatus is implanted in the body to shield the signal electrode from electrical activity in the body.

24. The method of claim 23, wherein providing the second pressure sensor portion comprises providing a glass substrate material extending from a first side surface to a second side surface opposite the first side surface, and further wherein the signal electrode is formed on and in direct contact with first side surface of the glass substrate material.

25. The method of claim 24, wherein the method further comprises electrically connecting the signal electrode provided on and in direct contact with the glass substrate material to one or more die of the pressure sensor apparatus via conductive material patterned on at least a portion of the glass substrate material.

26. The method of claim 24, wherein the method further comprises defining one or more openings through the glass substrate material, and electrically connecting the signal electrode provided on and in direct contact with the glass substrate material to one or more die of the pressure sensor apparatus via conductive material formed in the one or more openings.

27. The method of claim 23, wherein providing the second pressure sensor portion comprises:

providing a substrate material;

defining at least one trench through at least a portion thereof; and

filling the at least one trench with the insulator material, wherein the signal electrode is formed on and in direct contact with the insulator material.

28. The method of claim 27, wherein the substrate material comprises a silicon substrate material, and further wherein the insulator material comprises a glass insulator material, wherein the signal electrode is formed on and in direct contact with the glass insulator material.

29. The method of claim 27, wherein defining the at least one trench comprises defining that at least one trench through an entire thickness thereof, wherein the at least one trench is filled with the insulator material, and further wherein the signal electrode is provided on and in direct contact with the insulator material.

30. The method of claim 27, wherein defining the at least one trench comprises defining at least one trench through the back side of a silicon substrate material, wherein the at least one trench is filled with a glass insulator material, and further wherein the signal electrode is provided on and in direct contact with the glass insulator material.

31. The method of claim 23, wherein the method further comprises bonding the first pressure sensor portion to the second pressure sensor portion such that a gap is provided between the diaphragm electrode and the signal electrode.

32. The method of claim 31, wherein bonding the first pressure sensor portion to the second pressure sensor portion further defines at least one die cavity provided between the first pressure sensor portion and the second pressure sensor portion, and wherein the method further comprises:

forming one or more metallization connections between the signal electrode and die cavity for connection of the signal electrode to one or more die positioned in the die cavity; and

electrically isolating the one or more metallization connections using the insulator material.

33. The method of claim 23, wherein the method further comprises:

providing a third pressure sensor portion;

bonding the second pressure sensor portion to the third pressure sensor portion such that at least one die cavity is provided between the second pressure sensor portion and the third pressure sensor portion; and

forming one or more metallization connections between the signal electrode and die cavity for connection of the signal electrode to one or more die positioned in the die cavity.

34. The method of claim 33, wherein the method further comprises providing a power source in the at least one die cavity, and connecting the one or more die positioned in the at least one die cavity such that signals can be transmitted wirelessly from the pressure sensor apparatus.

35. The method of claim 23, wherein providing the first pressure sensor portion comprises:

providing a substrate material;

defining a recess in the substrate material to provide at least a part of the gap between the diaphragm electrode and the signal electrode.

36. The method of claim 35, wherein providing the substrate material comprises providing a silicon substrate material, wherein the recess is defined in the silicon substrate material to provide at least a part of the gap between the diaphragm electrode and the signal electrode, and further wherein providing the second pressure sensor portion comprises providing a planar glass substrate material upon which the signal electrode is directly provided.

37. The method of claim 23, wherein providing the second pressure sensor portion comprises:

providing a substrate material; and

defining a recess in the substrate material to provide at least a part of the gap between the diaphragm electrode and the signal electrode.

38. The method of claim 37, wherein providing the substrate material comprises providing a glass substrate material, wherein the recess is defined in the glass substrate material to provide at least a part of the gap between the diaphragm electrode and the signal electrode.

39. The method of claim 23, wherein providing at least one of the first pressure sensor portion and the second pressure sensor portion comprises:

providing a substrate material; and

patterning one or more layers formed on the substrate material to define at least one opening to provide at least a part of the gap between the diaphragm electrode and the signal electrode.