In-situ cap and method of fabricating same for an integrated circuit device

• US 6,465,280 B1
• Filed: 03/07/2001
• Issued: 10/15/2002
• Est. Priority Date: 03/07/2001
• Status: Expired due to Term

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Martin, John R., Morrison, Richard H. Jr.
• Primary Examiner(s): Smith, Matthew
• Assistant Examiner(s): Keshavan, Belur V
• Application Number:
  US09/800,821
• Time in Patent Office: 587 Days
• Field of Search: 438/125, 438/106, 438/127, 438/121, 438/123, 438/124, 257/704, 257/687, 257/417, 257/659
• US Class Current: 438/125
• CPC Class Codes: B81B 7/0064 for protecting against electromagnetic or electrostatic interferences
• CPC Class Codes: B81B 7/0077 Other packages not provided for in groups B81B7/0035 - B81B7/0074
• CPC Class Codes: B81C 2203/0136 Growing or depositing of a covering layer
• CPC Class Codes: B81C 2203/0145 Hermetically sealing an opening in the lid
• CPC Class Codes: B81C 2203/0154 Moulding a cap over the MEMS device
• CPC Class Codes: H01H 59/0009 making use of micromechanics
• CPC Class Codes: H01L 21/50 Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 23/10 characterised by the material or arrangement of seals between parts, e.g. between cap and base of the container or between leads and walls of the container
• 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
• CPC Class Codes: H01L 2924/1433 Application-specific integrated circuit [ASIC]

Abstract

An in-situ cap for an integrated circuit device such as a micromachined device and a method of making such a cap by fabricating an integrated circuit element on a substrate; forming a support layer over the integrated circuit element and forming a cap structure in the support layer covering the integrated circuit element.

Claims

1. A method of fabricating an in-situ cap for a micromachined device comprising:

fabricating a micromachined element on a substrate with a sacrificial support layer intact;

fabricating a cap sacrificial support layer over said micromachined element;

forming a cap structure in said sacrificial support layers covering said micromachined element; and

removing the sacrificial support layers within said cap structure to release said micromachined element leaving an in-situ cap integrated with the element.

2. The method of claim 1 in which forming said cap structure includes forming a cap hole around said element.

3. The method of claim 2 in which forming said cap structure includes filling said cap hole to form a cap wall and covering said sacrificial support layers to form a top connected with said cap wall.

4. The method of claim 1 in which said cap is formed with at least one hole.

5. The method of claim 4 in which removing the sacrificial support layers includes introducing a release agent through said at least one hole in said cap.

6. The method of claim 4 in which said substrate is formed with at least one hole.

7. The method of claim 6 in which removing the sacrificial support layers includes introducing a release agent through said at least one hole in said substrate.

8. The method of claim 4 in which the cap hole is closed to seal the cap.

9. The method of claim 4 in which a fluid filler is introduced through the at least one hole in said cap surrounding the micromachined element.

10. The method of claim 6 in which the cap hole is closed to seal the cap.

11. The method of claim 6 in which a fluid filler is introduced through the at least one hole in said cap surrounding the micromachined element.

12. The method of claim 9 in which said cap hole is closed to seal in the fluid.

13. The method of claim 9 in which said cap hole is small and the surface tension of the fluid prevents its escape.

14. The method of claim 1 in which fabricating a cap includes forming a contact tip on said cap.

15. The method of claim 14 in which said micromachined element includes a switch and said contact tip is a terminal of said switch.

16. The method of claim 15 in which fabricating a cap includes forming a gate electrode on said cap for operating said switch.

17. A method of fabricating an in-situ cap for an integrated circuit element comprising:

fabricating an integrated circuit element on a substrate;

forming a support layer over said integrated circuit element; and

forming a cap structure in said support layer covering said integrated circuit element.

18. The method of claim 17 further including removing the support layer within said cap structure.

19. The method of claim 17 in which forming said cap structure includes forming a cap hole around said element.

20. The method of claim 19 in which forming said cap structure includes filling said cap hole to form a cap wall and covering said support layer to form a top connected with said cap wall.

21. The method of claim 17 in which said cap is formed with at least one hole and removing the support layer includes introducing a release agent through said hole in said cap.

22. The method of claim 17 in which said substrate is formed with at least one hole and removing the support layer includes introducing a release agent through said hole in said substrate.

23. The method of claim 21 in which the cap hole is closed to seal the cap.

24. The method of claim 21 in which a fluid filler is introduced through the cap hole into the cap surrounding the micromachined device.

25. The method of claim 24 in which said cap hole is closed to seal in the fluid.

26. The method of claim 24 in which the fluid is,a crosslinkable material.

27. The method of claim 21 in which a gas is introduced through the cap hole into the cap to modify at least one surface inside the cap.

28. The method of claim 24 in which said cap hole is small and the surface tension of the fluid prevents its escape.

29. The method of claim 17 in which fabricating a cap includes forming a contact tip on said cap.

30. The method of claim 29 in which said integrated circuit element includes a switch and said contact tip is a terminal of said switch.

31. The method of claim 30 in which fabricating a cap includes forming a gate electrode on said cap for operating said switch.