Thermally compensating dieletric anchors for microstructure devices

• US 8,570,122 B1
• Filed: 05/13/2010
• Issued: 10/29/2013
• Est. Priority Date: 05/13/2009
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: RF Micro Devices Incorporated (Qorvo, Inc.)
• Inventors: Hammond, Jonathan Hale
• Primary Examiner(s): Rojas, Bernard
• Application Number:
  US12/779,307
• Time in Patent Office: 1,265 Days
• Field of Search: 335/78, 200/181
• US Class Current: 335/78
• CPC Class Codes: B81B 2201/014 having a cantilever fixed on one side connected to one or more dimples
• CPC Class Codes: B81B 7/0019 Protection against thermal alteration or destruction B81B7/0083 takes precedence
• CPC Class Codes: H01H 59/0009 making use of micromechanics

Abstract

A microstructure device that includes at least one thermally compensating anchor for preventing undesirable thermal displacement or actuation during manufacturing or operation is disclosed. In particular, the microstructure device includes a substrate and a movable structure suspended above the substrate by at least one anchor. The anchor is attached to the substrate. The anchor also includes an upper area of an upper surface region of a bottom portion attached to a lower surface of a proximal portion of the movable structure. The anchor further includes a top portion having a lower area of a lower surface region attached to an upper surface of the proximal portion of the movable structure, wherein the lower surface region of the top portion and the upper surface region of the bottom portion are geometrically asymmetric.

Claims

1. A microstructure device comprising:

a substrate; and

a movable structure having an upper surface, a lower surface, a proximal portion, and a distal portion suspended above the substrate by at least one anchor homogenously formed from a dielectric material with a bottom portion having a bottom area of a bottom surface region attached to the substrate and an upper area of an upper surface region attached to the lower surface of the proximal portion of the movable structure, the at least one anchor further including a top portion having a lower area of a lower surface region attached to the upper surface of the proximal portion of the movable structure, wherein the lower surface region of the top portion and the upper surface region of the bottom portion are geometrically asymmetric.

2. The microstructure device of claim 1 wherein the lower surface region of the top portion and the upper surface region of the bottom portion are geometrically asymmetric due to the lower surface region of the top portion extending further towards the distal portion of the movable structure than the upper surface region of the bottom portion.

3. The microstructure device of claim 2 wherein the distal portion of the movable structure is urged away from the substrate by a thermally induced mechanical stress as the substrate, the movable structure, and the at least one anchor are heated.

4. The microstructure device of claim 1 wherein the lower surface region of the top portion and the upper surface region of the bottom portion are geometrically asymmetric due to a measurable difference between a size of the lower area of the lower surface region of the top portion and a size of the upper area of the upper surface region of the bottom portion.

5. The microstructure device of claim 4 wherein the lower surface region of the top portion extends further towards the distal portion of the movable structure than the upper surface region of the bottom portion.

6. The microstructure device of claim 4 wherein the upper surface region of the bottom portion is formed from a plurality of spaced dielectric strips that are oriented longitudinally towards the distal portion of the movable structure.

7. The microstructure device of claim 4 wherein the lower surface region of the top portion extends further towards the distal portion of the movable structure than does the upper surface region of the bottom portion, and wherein the lower surface region of the top portion extends further over the proximal portion of the movable structure than does the upper surface region of the bottom portion.

8. The microstructure device of claim 4 wherein the lower area of the lower surface region of the top portion is larger than the upper area of the upper surface region of the bottom portion, and wherein the bottom portion is divided and spaced such that the lower area of the lower surface region of the top portion does not overlap the upper area of the upper surface region of the bottom portion.

9. The microstructure device of claim 4 wherein the lower area of the lower surface region of the top portion is smaller than the upper area of the upper surface region of the bottom portion, and wherein the bottom portion is divided and spaced such that the lower area of the lower surface region of the top portion does not overlap the upper area of the upper surface region of the bottom portion.

10. The microstructure device of claim 1 wherein the lower surface region of the top portion and the upper surface region of the bottom portion are geometrically asymmetric due to the lower surface region of the top portion being thicker than the upper surface region of the bottom portion.

11. The microstructure device of claim 1 wherein the movable structure is supported by at least two anchors.

12. The microstructure device of claim 1 wherein the lower area of the lower surface region of the top portion is equal to the upper area of the upper surface region of the bottom portion, and wherein the lower surface region of the top portion and the upper surface region of the bottom portion are geometrically asymmetric due to the bottom portion being divided and spaced such that the lower area of the lower surface region of the top portion does not overlap the upper area of the upper surface region of the bottom portion.

13. The microstructure device of claim 1 wherein the lower area of the lower surface region of the top portion is equal to the upper area of the upper surface region of the bottom portion, and wherein the lower surface region of the top portion and the upper surface region of the bottom portion are geometrically asymmetric due to the lower area of the lower surface region extending further towards the distal portion of the movable structure than the upper area of the upper surface region of the bottom portion, and due to the upper area of the upper surface region extending further towards the proximal portion of the movable structure than the lower area of the lower surface region of the top portion.

14. A semiconductor device comprising:

a substrate comprising a handle layer, an insulator layer over the handle layer, and a device layer over the handle layer in which a plurality of active semiconductor devices is formed; and

a microstructure integrally formed on the substrate, the microstructure comprising;

a movable structure having an upper surface, a lower surface, a proximal portion, and a distal portion suspended above the substrate by at least one anchor homogenously formed from a dielectric material with a bottom portion having a bottom area of a bottom surface region attached to the substrate and an upper area of an upper surface region attached to the lower surface of the proximal portion of the movable structure, the at least one anchor further including a top portion having a lower area of a lower surface region attached to the upper surface of the proximal portion of the movable structure, wherein the lower surface region of the top portion and the upper surface region of the bottom portion are geometrically asymmetric.

15. The semiconductor device of claim 14 wherein the lower surface region of the top portion and the upper surface region of the bottom portion comprising the microstructure are geometrically asymmetric due to the lower surface region of the top portion extending further towards the distal portion of the movable structure than the upper surface region of the bottom portion.

16. The semiconductor device of claim 15 wherein the distal portion of the movable structure of the microstructure is urged away from the substrate by a thermally induced mechanical stress as the substrate, the movable structure, and the at least one anchor are heated.

17. The semiconductor device of claim 14 wherein the lower surface region of the top portion and the upper surface region of the bottom portion of the microstructure are geometrically asymmetric due to a measurable difference between a size of the lower area of the lower surface region of the top portion and a size of the upper area of the upper surface region of the bottom portion.

18. The semiconductor device of claim 17 wherein the lower surface region of the top portion extends further towards the distal portion of the movable structure than the upper surface region of the bottom portion.

19. The semiconductor device of claim 17 wherein the upper surface region of the bottom portion is formed from a plurality of spaced dielectric strips that are oriented longitudinally towards the distal portion of the movable structure.

20. The semiconductor device of claim 17 wherein the lower surface region of the top portion extends further towards the distal portion of the movable structure than does the upper surface region of the bottom portion, and wherein the lower surface region of the top portion extends further over the proximal portion of the movable structure than does the upper surface region of the bottom portion.

21. The semiconductor device of claim 17 wherein the lower area of the lower surface region of the top portion is larger than the upper area of the upper surface region of the bottom portion, and wherein the bottom portion is divided and spaced such that the lower area of the lower surface region of the top portion does not overlap the upper area of the upper surface region of the bottom portion.

22. The semiconductor device of claim 17 wherein the lower area of the lower surface region of the top portion is smaller than the upper area of the upper surface region of the bottom portion, and wherein the bottom portion is divided and spaced such that the lower area of the lower surface region of the top portion does not overlap the upper area of the upper surface region of the bottom portion.

23. The semiconductor device of claim 14 wherein the lower surface region of the top portion of the microstructure and the upper surface region of the bottom portion of the microstructure are geometrically asymmetric due to the lower surface region of the top portion being thicker than the upper surface region of the bottom portion.

24. The semiconductor device of claim 14 wherein the movable structure of the microstructure is supported by at least two anchors.

25. The semiconductor device of claim 14 wherein the lower area of the lower surface region of the top portion of the microstructure is equal to the upper area of the upper surface region of the bottom portion of the microstructure, and wherein the lower surface region of the top portion and the upper surface region of the bottom portion are geometrically asymmetric due to the bottom portion being divided and spaced such that the lower area of the lower surface region of the top portion does not overlap the upper area of the upper surface region of the bottom portion.

26. The semiconductor device of claim 14 wherein the lower area of the lower surface region of the top portion of the microstructure is equal to the upper area of the upper surface region of the bottom portion of the microstructure, and wherein the lower surface region of the top portion and the upper surface region of the bottom portion are geometrically asymmetric due to the lower area of the lower surface region extending further towards the distal portion of the movable structure than the upper area of the upper surface region of the bottom portion, and due to the upper area of the upper surface region extending further towards the proximal portion of the movable structure than the lower area of the lower surface region of the top portion.

27. A microstructure device comprising:

a substrate; and

a movable structure having an upper surface, a lower surface, a proximal portion, and a distal portion suspended above the substrate by at least one anchor with a continuous structure formed from a dielectric material with a bottom portion having a bottom area of a bottom surface region attached to the substrate and an upper area of an upper surface region attached to the lower surface of the proximal portion of the movable structure, the at least one anchor further including a top portion having a lower area of a lower surface region attached to the upper surface of the proximal portion of the movable structure, wherein the lower surface region of the top portion and the upper surface region of the bottom portion are geometrically asymmetric.