METHOD OF MAKING A MICRO-ELECTRO-MECHANICAL-SYSTEMS (MEMS) DEVICE

• US 20120107993A1
• Filed: 10/29/2010
• Published: 05/03/2012
• Est. Priority Date: 10/29/2010
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Karlin, Lisa H., Liu, Lianjun, Steimle, Robert F., Kierst, David W., Liu, Wei, Montez, Ruben
• Granted Patent: US 8,455,286 B2
• Time in Patent Office: Days
• US Class Current: 438/50
• CPC Class Codes: B81B 2207/07 Interconnects
• CPC Class Codes: B81C 1/00801 Avoid alteration of functional structures by etching, e.g. using a passivation layer or an etch stop layer B81C1/00595, B81C1/00468 take precedence
• CPC Class Codes: B81C 2201/053 Depositing a protective layers

Abstract

A method of forming a MEMS device includes forming a sacrificial layer over a substrate. The method further includes forming a metal layer over the sacrificial layer and forming a protection layer overlying the metal layer. The method further includes etching the protection layer and the metal layer to form a structure having a remaining portion of the protection layer formed over a remaining portion of the metal layer. The method further includes etching the sacrificial layer to form a movable portion of the MEMS device, wherein the remaining portion of the protection layer protects the remaining portion of the metal layer during the etching of the sacrificial layer to form the movable portion of the MEMS device.

Claims

1. A method of forming a MEMS device, the method comprising:

forming a sacrificial layer over a substrate;

forming a metal layer over the sacrificial layer;

forming a protection layer overlying the metal layer;

etching the protection layer and the metal layer to form a structure having a remaining portion of the protection layer formed over a remaining portion of the metal layer; and

etching the sacrificial layer to form a movable portion of the MEMS device, wherein the remaining portion of the protection layer protects the remaining portion of the metal layer during the etching of the sacrificial layer to form the movable portion of the MEMS device.

2. The method of claim 1, wherein a material used to form the protection layer and a thickness of the protection layer are selected such that after the step of the etching the sacrificial layer to form the movable portion of the MEMS device, a residual portion of the remaining portion of the protection layer remains over the remaining portion of the metal layer.

3. The method of claim 1 further comprising:

after etching the protection layer and the metal layer to form the structure, forming an insulating layer overlying the remaining portion of the protection layer.

4. The method of claim 1, wherein the structure comprises a bond pad structure.

5. The method of claim 1 further comprising:

forming a conductive layer over the sacrificial layer; and

prior to etching the sacrificial layer to form the movable portion of the MEMS device, etching the conductive layer to form a feature of the movable portion.

6. The method of claim 1, wherein the protection layer comprises one of a group consisting of silicon-rich silicon nitride, titanium nitride, titanium, amorphous carbide.

7. The method of claim 1, wherein the protection layer comprises silicon-rich silicon nitride.

19. The method of claim 1, wherein the protection layer comprises silicon-rich nitride.

8. A method of forming a MEMS device, the method comprising:

forming a sacrificial layer over a substrate;

forming a metal layer over the sacrificial layer;

etching the metal layer to form a structure having a remaining portion of the metal layer;

forming a protection layer overlying at least the remaining portion of the metal layer; and

etching the sacrificial layer to form a movable portion of the MEMS device, wherein the protection layer protects the remaining portion of the metal layer during the etching of the sacrificial layer to form the movable portion of the MEMS device.

9. The method of claim 8, wherein a material used to form the protection layer and a thickness of the protection layer are selected such that after the step of the etching the sacrificial layer to form the movable portion of the MEMS device, a residual portion of the sacrificial layer remains over the remaining portion of the metal layer.

10. The method of claim 8 further comprising:

prior to etching the protection layer, forming an insulating layer overlying the protection layer.

11. The method of claim 8, wherein the structure comprises a bond pad structure.

12. The method of claim 8 further comprising:

forming a conductive layer over the sacrificial layer; and

prior to etching the sacrificial layer to form the movable portion of the MEMS device, etching the conductive layer to form a feature of the movable portion.

13. The method of claim 8, wherein the protection layer comprises one of a group consisting of silicon-rich silicon nitride, titanium nitride, titanium, and amorphous carbide.

14. The method of claim 8, wherein the protection layer comprises silicon-rich nitride.

15. A method of forming a MEMS device, the method comprising:

forming a sacrificial layer over a substrate;

forming a metal layer over the sacrificial layer;

forming a protection layer overlying the metal layer;

etching the protection layer and the metal layer to form a bond pad structure having a remaining portion of the protection layer formed over a remaining portion of the metal layer;

forming an insulating layer overlying at least the remaining portion of the protection layer; and

etching the sacrificial layer to form a movable portion of the MEMS device, wherein the remaining portion of the protection layer protects at least a top surface of the remaining portion of the metal layer, forming the bond pad structure, from contamination during the step of etching the sacrificial layer to form the movable portion of the MEMS device.

16. The method of claim 15, wherein a material used to form the protection layer and a thickness of the protection layer are selected such that after the step of the etching the sacrificial layer to form the movable portion of the MEMS device, a residual portion of the remaining portion of the sacrificial layer remains over the remaining portion of the metal layer.

17. The method of claim 15 further comprising:

forming a conductive layer over the sacrificial layer; and

prior to etching the sacrificial layer to form the movable portion of the MEMS device, etching the conductive layer to form a feature of the movable portion.

18. The method of claim 15, wherein the protection layer is selected from a group consisting of silicon nitride and titanium nitride.

20. The method of claim 16, wherein the protection layer comprises one of a group consisting of silicon-rich silicon nitride, titanium nitride, titanium, and amorphous carbide.