Oxide retainer method for MEMS devices

• US 8,993,362 B1
• Filed: 07/22/2011
• Issued: 03/31/2015
• Est. Priority Date: 07/23/2010
• Status: Active Grant

• Current Assignee: Movella Incorporated (Movella Holdings, Inc.)
• Original Assignee: mCube, Inc.
• Inventors: Flannery, Anthony F. Jr.
• Primary Examiner(s): CHEN, JACK S J
• Application Number:
  US13/189,471
• Time in Patent Office: 1,348 Days
• Field of Search: 438/26, 438/48, 438/50, 438/51, 438/53, 257/E21.214
• US Class Current: 438/53
• CPC Class Codes: B81B 2207/015 the micromechanical device and the control or processing electronics being integrated on the same substrate
• CPC Class Codes: B81C 1/00944 Maintaining a critical distance between the structures to be released
• CPC Class Codes: B81C 2201/056 Releasing structures at the end of the manufacturing process

Abstract

A method and structure for fabricating a monolithic integrated MEMS device. The method includes providing a substrate having a surface region and forming at least one conduction material and at least one insulation material overlying at least one portion of the surface region. At least one support structure can be formed overlying at least one portion of the conduction and insulation surface regions, and at least one MEMS device can be formed overlying the support structure(s) and the conduction and insulation surface regions. In a variety of embodiments, the support structure(s) can include dielectric or oxide materials. The support structure(s) can then be removed and a cover material can be formed overlying the MEMS device(s), the conduction and insulation materials, and the substrate. In various embodiments, the removal of the support structure(s) can be accomplished via a vapor etching process.

Claims

1. A method for fabricating a monolithically integrated MEMS device, the method comprising:

providing a substrate having a surface region;

forming at least one insulation material overlying at least one portion of the surface region, the insulation material having an insulation surface region;

forming at least one conduction material overlying the at least one portion of the surface region, the conduction material having a conduction surface region;

forming multiple oxide retainers, each oxide retainer including a patterned small support structure overlying at least one portion of the conduction and insulation surface regions;

forming at least one MEMS device overlying at least one portion of the conduction and insulation surface regions, the MEMS device(s) overlying the oxide retainers, the oxide retainers being configured to support the MEMS device and to reduce stiction;

removing the oxide retainers, the oxide retainers being configured to reduce diffusion limitation of the removal process; and

forming a cover material overlying the MEMS device, at least one portion of the conduction and insulation materials, and at least one portion of the substrate.

2. The method of claim 1 further comprising forming an integrated circuit (IC) layer overlying at least one portion of the surface region, the IC layer having an IC surface region.

3. The method of claim 2 wherein the insulation and conduction material(s) are formed overlying at least one portion of the IC surface region.

4. The method of claim 1 wherein the insulation material comprises a first dielectric material.

5. The method of claim 4 wherein the forming of the support structure(s) comprises forming a second dielectric material overlying the insulation and conduction surface regions and removing at least a portion of the second dielectric material.

6. The method of claim 5 wherein the second dielectric material comprises an oxide material or a silicon dioxide material.

7. The method of claim 1 wherein the support structure(s) comprise at least one oxide retainer, small patterned support, or bond support.

8. The method of claim 1 wherein the MEMS device(s) comprise at least one MEMS sensor, MEMS actuator, or MEMS structure.

9. The method of claim 1 wherein the removing of the support structure(s) comprises a wet etching, dry etching, or mechanical process.

10. The method of claim 1 wherein the removing of the support structure(s) comprises a Hydrogen Fluoride (HF) vapor etching process.

11. A method of fabricating a monolithically integrated MEMS device, the method comprising:

providing a substrate having a surface region;

forming an integrated circuit (IC) layer overlying at least one portion of the surface region, the IC layer having an IC surface region;

forming at least one first dielectric material overlying at least one portion of the IC surface region and the surface region, the first dielectric material having a first dielectric surface region;

forming at least one metal material overlying at least one portion of the IC surface region and the surface region, the metal material(s) having a conduction surface region;

forming multiple oxide retainers, each oxide retainer including a patterned small support structure overlying at least one portion of the conduction and first dielectric surface regions;

forming at least one MEMS device overlying at least one portion of the conduction and first dielectric surface regions, the MEMS device(s) having a high aspect ratio and being configured overlying the oxide retainers, the oxide retainers being configured to support the MEMS device and to reduce stiction;

removing the oxide retainers, the oxide retainers being configured to reduce diffusion limitation of the removal process, the removal process including a Hydrogen Fluoride (HF) vapor etching process; and

forming a cover material overlying the MEMS device, at least one portion of the conduction and first dielectric surface regions, and at least one portion of the IC surface region.

12. The method of claim 11 wherein the first dielectric material(s) and metal material(s) are formed overlying at least one portion of the IC surface region.

13. The method of claim 11 wherein the forming of the support structure(s) comprises forming a second dielectric material and removing at least a portion of the second dielectric material.

14. The method of claim 13 wherein the first and second dielectric materials comprise oxide materials or silicon dioxide materials.

15. The method of claim 11 wherein the support structure(s) comprise at least one oxide retainer, small patterned support, or bond support.

16. The method of claim 11 wherein the MEMS device(s) comprise at least one MEMS sensor, MEMS actuator, or MEMS structure.

17. The method of claim 11 wherein the MEMS device(s) are formed by a wet etching, dry etching, or mechanical process.

18. The method of claim 11 wherein the removing of the support structure(s) comprises a wet etching, dry etching, or mechanical process.

19. The method of claim 11 wherein the removing of the support structure(s) comprises a Hydrogen Fluoride (HF) vapor etching process.

20. A method for fabricating a monolithic integrated MEMS device, the method comprising:

forming multiple oxide retainers, each oxide retainer including a patterned small support structure overlying at least a portion of a first dielectric and metal surface region(s), the oxide retainers being formed from a dielectric material via an etching process, the oxide retainers being sized and spatially configured to allow for quick removal of the oxide retainers and to reduce stiction and to prevent the removal of the oxide retainers from being diffusion limited;

forming at least one MEMS device overlying at least one portion of the first dielectric and metal surface region(s), the MEMS device(s) having a high aspect ratio and being configured overlying the oxide retainers;

removing the oxide retainers via a Hydrogen Fluoride (HF) vapor etching process; and

forming a cover material overlying the MEMS device(s), at least one portion of the metal and first dielectric surface regions, and at least one portion of the substrate.