Micro-electro-mechanical system (MEMS) structures and design structures

• US 9,233,832 B2
• Filed: 05/10/2013
• Issued: 01/12/2016
• Est. Priority Date: 05/10/2013
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: GlobalFoundries, Inc.
• Inventors: Stamper, Anthony K.
• Primary Examiner(s): Weiss, Howard
• Assistant Examiner(s): GARCES, NELSON Y
• Application Number:
  US13/891,294
• Publication Number:
  US 20140332913A1
• Time in Patent Office: 977 Days
• Field of Search: 257413-423
• US Class Current: 1/1
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface

Abstract

Dummy Micro-Electro-Mechanical System (MEMS) structures, methods of manufacture and design structures are disclosed. The method includes forming a bumper extending from a Micro-Electro-Mechanical System (MEMS) beam structure provided within a cavity structure. The method further includes forming a dummy landing structure on an opposing side of the cavity structure from the MEMS beam, which is laterally offset from the bumper when the MEMS beam is in a non-actuated state.

Claims

1. A method, comprising:

forming a bumper extending from a Micro-Electro-Mechanical System (MEMS) beam structure provided within a cavity structure; and

forming a dummy landing structure on an opposing side of the cavity structure from the MEMS beam, which is laterally offset in a horizontal direction from the bumper when the MEMS beam is in a non-actuated state and which the bumper lands on when the MEMS beam is in an actuated state.

2. The method of claim 1, wherein the bumper is a dielectric bumper and the dummy landing structure is a metal or metal alloy.

3. The method of claim 2, wherein the metal or metal alloy dummy landing structure is coated in dielectric material.

4. The method of claim 1, wherein:

the forming of the dummy landing structure comprises determining beam distortion and extended landings caused by thermal coefficient mismatch of materials during operating conditions; and

the forming of the dummy landing structure comprises accounting for mismatches in thermal coefficients of materials used in fabrication process of the MEMS beam.

5. The method of claim 1, wherein the forming of the dummy landing structure comprises accounting for variability in nominal offset due to stress/thickness/width variation due to process variations in MEMS beam structure.

6. The method of claim 1, wherein the forming of the dummy landing structure comprises accounting for at least one processing condition of a fabrication process for the MEMS beam or other MEMS structures.

7. The method of claim 6, wherein the at least one processing condition of the fabrication process comprises at least one of variations in material deposition used to form the MEMS beam, lithographic overlay and width, thickness, residual stress tolerance, and location of the bumper.

8. The method of claim 1, wherein the forming of the dummy landing structure comprises accounting for offset due to MEMS variability and temperature-induced stress changes in the MEMS beam.

9. The method of claim 1, wherein the forming of the dummy landing structure comprises accounting for lateral movement of the MEMS beam caused by beam residual stress variability due to a tensile or compressive force.

10. The method of claim 9, wherein the types of MEMS beam includes accounting for dimensions and spring constants of the MEMS beam.

11. The method of claim 9, wherein the forming of the dummy landing structure further comprises accounting for at least one of travel distance of the MEMS beam, acceleration of the MEMS beam, spacing of the MEMS beam away from the dummy landing structure, spring constant of the MEMS beam, actuation voltage, operating temperatures, and cycle times.

12. The method of claim 1, wherein the forming of the dummy landing structure further comprises forming the dummy landing structure larger than the bumper.

13. The method of claim 1, wherein the forming of the dummy landing structure further comprises forming the dummy landing structure in alignment with the bumper when the MEMS beam is fully actuated.

14. The method of claim 1, wherein the forming of the dummy landing structure further comprises forming the dummy landing structure at an offset of approximately 0.8+/−

0.4 μ

m.

19. The method of claim 1, wherein the forming of the bumper comprises:

forming a layer of sacrificial material on a substrate used to form a lower portion of the cavity;

forming at least one recess within the sacrificial material;

depositing an insulator material within the at least one recess;

forming the MEMS beam on the sacrificial material and the insulator material; and

venting the sacrificial material.

20. The method of claim 1, wherein the forming of the bumper comprises:

forming a layer of sacrificial material under the MEMS beam;

forming at least one recess within the sacrificial material;

depositing an insulator material within the at least one recess formed in the sacrificial material; and

venting the sacrificial material.

15. A method comprising determining a size and/or location offset of a dummy landing structure with respect to a bumper of insulator material by accounting for at least one of process variations of fabricating a MEMS structure and affects of operating conditions on the MEMS structure such that the bumper always lands on the dummy landing structure and does not contact an actuator of the MEMS structure during actuation.

16. The method of claim 15, wherein the operating conditions comprise at least temperature changes of a MEMS beam of the MEMS structure and beam residual stress variability placed on the MEMS beam during operation.

17. The method of claim 16, wherein the beam residual stress variability results in an offset and/or distortion of the MEMS beam.

18. The method of claim 15, wherein the process variations include lithographic overlay and width, stress and thickness variability of a MEMS beam of the MEMS structure.