Method of accurately spacing Z-axis electrode

• US 8,430,255 B2
• Filed: 03/19/2009
• Issued: 04/30/2013
• Est. Priority Date: 03/19/2009
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Candler, Robert N.
• Primary Examiner(s): Tran, Binh X
• Application Number:
  US12/407,584
• Publication Number:
  US 20100237039A1
• Time in Patent Office: 1,503 Days
• Field of Search: 216/17, 216/20, 216/39, 216/56
• US Class Current: 215/17
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81C 1/00682 Treatments for improving mechanical properties, not provided for in B81C1/00658 - B81C1/0065
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 25/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass testing, calibrating or compensating compasses G01C17/38
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up

Abstract

A method of forming a device with a controlled electrode gap width includes providing a substrate, forming a functional layer on top of a surface of the substrate, forming a sacrificial layer above the functional layer, exposing a first portion of the functional layer through the sacrificial layer, forming a first spacer layer on the exposed first portion of the functional layer, forming an encapsulation layer above the first spacer layer, and vapor etching the encapsulated first spacer layer to form a first gap between the functional layer and the encapsulation layer.

Claims

1. A method of forming a device with a controlled electrode gap width, comprising:

providing a substrate;

forming a functional layer on top of a surface of the substrate;

defining a movable member in the functional layer;

forming a sacrificial layer above the functional layer;

exposing a first portion of a top surface of the functional layer through the sacrificial layer;

forming a first spacer layer on the exposed first portion of the functional layer;

forming an encapsulation layer above the first spacer layer; and

vapor etching the encapsulated first spacer layer to form a first gap between the functional layer and the encapsulation layer.

2. The method of claim 1, wherein:

the movable member is a resonator structure; and

exposing a first portion of the functional layer comprises exposing a portion of the resonator structure.

3. The method of claim 2, wherein vapor etching the encapsulated spacer layer comprises:

vapor etching a portion of the sacrificial layer.

4. The method of claim 1, further comprising:

exposing a second portion of the functional layer through the sacrificial layer;

forming a second spacer layer on the exposed second portion of the functional layer;

forming the encapsulation layer above the second spacer layer; and

vapor etching the encapsulated second spacer layer to form a second gap between the functional layer and the encapsulation layer.

5. The method of claim 4, wherein the first spacer layer has a width for forming the first gap that is greater than a width of the second spacer layer for forming the second gap.

6. A method of forming a device with a controlled electrode gap width, comprising:

providing a substrate;

forming a functional layer on top of a surface of the substrate;

defining a movable member in the functional layer;

forming a sacrificial layer above the functional layer;

exposing a first portion of a top surface of the functional layer through the sacrificial layer;

forming a first spacer layer on the exposed first portion of the functional layer;

forming an encapsulation layer above the first spacer layer;

vapor etching the encapsulated first spacer layer to form a first gap between the functional layer and the encapsulation layer exposing a second portion of the functional layer through the sacrificial layer;

forming a second spacer layer on the exposed second portion of the functional layer;

forming a third spacer layer on the second spacer layer;

forming the encapsulation layer above the second spacer layer and the third spacer layer; and

vapor etching the encapsulated second spacer layer and the encapsulated third spacer layer to form a second gap between the functional layer and the encapsulation layer.

7. A method of forming a device with a z-axis electrode, comprising:

providing a substrate;

forming a functional layer on top of a surface of the substrate;

defining a movable member in the functional layer;

forming a sacrificial layer above the functional layer;

etching a first electrode hole in the sacrificial layer directly above a portion of the functional layer;

forming a first spacer layer within the first electrode hole;

forming a first encapsulation layer portion above the sacrificial layer and above the first spacer layer; and

removing the encapsulated first spacer layer.

8. The method of claim 7, further comprising:

forming at least one vent hole through the first encapsulation layer portion, wherein removing the encapsulated spacer layer further comprises;

vapor etching the spacer layer through the at least one vent hole.

9. The method of claim 7, further comprising:

forming a second encapsulation layer portion above the sacrificial layer.

10. The method of claim 7, further comprising:

forming at least one vent hole through the first encapsulation layer portion, wherein removing the encapsulated spacer layer further comprises;

vapor etching the spacer layer through the at least one vent hole.

11. The method of claim 7, further comprising:

etching a second electrode hole in the sacrificial layer;

forming a second spacer layer within the second electrode hole;

forming the first encapsulation layer portion above the second spacer layer; and

removing the encapsulated second spacer layer.

12. The method of claim 11, wherein the first spacer layer has a width for forming the first gap that is greater than a width of the second spacer layer for forming the second gap.

13. The method of claim 7, wherein:

the movable member is a resonator structure; and

etching a first electrode hole comprises exposing a portion of the resonator structure.

14. The method of claim 13, wherein removing the encapsulated first spacer layer comprises:

removing a portion of the sacrificial layer.

15. A method of forming a device with a z-axis electrode, comprising:

providing a substrate;

forming a functional layer on top of a surface of the substrate;

defining a first movable member in the functional layer;

forming a sacrificial layer above the defined movable member;

etching a first electrode hole in the sacrificial layer to expose an upper surface of the defined first movable member;

forming a first spacer layer within the first electrode hole;

forming a first encapsulation layer portion above the sacrificial layer and above the first spacer layer; and

removing the encapsulated first spacer layer.

16. The method of claim 15, further comprising:

forming a second encapsulation layer portion above the sacrificial layer.

17. The method of claim 15, further comprising:

defining a second movable member in the functional layer;

etching a second electrode hole in the sacrificial layer to expose an upper surface of the defined second movable member;

forming a second spacer layer within the second electrode hole;

forming the first encapsulation layer portion above the second spacer layer; and

removing the encapsulated second spacer layer.

18. The method of claim 17, wherein the first spacer layer has a width for forming the first gap that is greater than a width of the second spacer layer for forming the second gap.

19. The method of claim 15, wherein:

defining a first movable member comprises defining a resonator structure.

20. The method of claim 19, wherein removing the encapsulated first spacer layer comprises:

removing a portion of the sacrificial layer.