INTEGRATED DEVICE FABRICATED USING ONE OR MORE EMBEDDED MASKS

• US 20080284028A1
• Filed: 06/23/2008
• Published: 11/20/2008
• Est. Priority Date: 03/31/2005
• Status: Abandoned Application

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Greywall, Dennis S.
• Application Number:
  US12/144,191
• Publication Number:
  US 20080284028A1
• Time in Patent Office: Days
• US Class Current: 257/758
• CPC Class Codes: B81B 2201/033 Comb drives
• CPC Class Codes: B81C 1/00404 Mask characterised by its size, orientation or shape

Abstract

A device fabricated using a multi-layered wafer that has an embedded etch mask adapted to map a desired device structure onto an adjacent (poly)silicon layer. Due to the presence of the embedded mask, it becomes possible to delay the etching that forms the mapped structure in the (poly)silicon layer until a relatively late fabrication stage. As a result, flatness of the (poly)silicon layer is preserved for the deposition of any necessary over-layers, which substantially obviates the need for filling the voids created by the structure formation with silicon oxide.

Claims

1-13. -13. (canceled)

14. An integrated device, comprising:

a multi-layer wafer having a first side and a second side;

a first structure formed in a first layer of the wafer, said first structure having a first outline pattern; and

a second structure formed in a second layer of the wafer, said second structure having a second outline pattern, wherein;

the wafer has an opening in the first side, which exposes the first and second structures, said opening having a third outline pattern, wherein the third outline pattern substantially encloses the first and second outline patterns;

the second layer has a greater offset distance from the first side than the first layer; and

the second outline pattern substantially encloses the first outline pattern.

15. The device of claim 14, further comprising a third structure formed in the second layer, said third structure having a fourth outline pattern, wherein:

the third outline pattern substantially encloses the fourth outline pattern; and

the fourth outline pattern does not overlap with the second outline pattern.

16. The device of claim 15, wherein:

the wafer comprises a substrate layer;

the first structure is fixedly connected to the substrate layer; and

the third structure is movable with respect to the substrate layer.

17. The device of claim 16, wherein the second structure is fixedly connected to the substrate layer.

18. The device of claim 16, wherein:

the first and third structures are electrically isolated from one another; and

the first and third structures are portions of a motion actuator, wherein the third structure is adapted to move in response to a voltage differential between the first and third structures so as to change, for the third structure, an offset distance from the first side.

19. The device of claim 16, wherein the first and second structures are in electrical contact with each other and the substrate layer.

20. The device of claim 14, wherein each of the first and second layers is a buried layer located between outer layers of the wafer.

21. The device of claim 14, wherein:

the wafer comprises a substrate layer; and

the opening penetrates the substrate layer.

22. The device of claim 14, wherein at least one of the first and second structures defines a via, well, or trench having an aspect ratio of about 5:

1 or greater.

23. The device of claim 14, wherein at least one of the first and second layers comprises silicon.

24. The device of claim 14, wherein at least one of the first and second layers has a thickness of at least about 10 μ

m.

25. The device of claim 14, wherein the wafer is part of a multi-wafer assembly.

26. The device of claim 25, wherein:

the wafer comprises a motion actuator and is a first wafer of the multi-wafer assembly; and

the multi-wafer assembly comprises a second wafer stacked with the first wafer so as to provide electrical leads to the motion actuator.

27. The device of claim 26, further comprising a movable mirror attached to the motion actuator, said movable mirror being one of independently movable segments of a segmented mirror.

28. The device of claim 14, wherein the device has been fabricated using a fabrication method comprising the steps of:

(A) forming first and second embedded masks in the wafer, wherein (i) the first embedded mask is in contact with the first layer and (ii) the second embedded mask is in contact with the second layer;

(B) etching, using an etchant, a portion of the first layer and a portion of the second layer from the wafer, wherein;

the first embedded mask protects a portion of the first layer corresponding to the first structure from being removed by the etchant during the etching;

the second embedded mask protects a portion of the second layer corresponding to the second structure from being removed by the etchant during the etching; and

the etchant is capable of removing material of the portions being protected by the first and second embedded masks; and

(C) removing at least one of the first and second embedded masks from the wafer.

29. The device of claim 18, further comprising a plate mounted on the third structure and adapted to move together with the third structure.