MICRO-ELECTRO-MECHANICAL SYSTEM (MEMS) STRUCTURES AND DESIGN STRUCTURES

• US 20130168782A1
• Filed: 01/03/2012
• Published: 07/04/2013
• Est. Priority Date: 01/03/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: JAHNES, Christopher V., STAMPER, Anthony K.
• Granted Patent: US 8,940,570 B2
• Time in Patent Office: Days
• US Class Current: 257/415
• CPC Class Codes: B81B 2201/0221 Variable capacitors
• CPC Class Codes: B81B 2203/0109 Bridges
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81B 2203/019 characterized by their profile
• CPC Class Codes: B81B 3/0008 Structures for avoiding electrostatic attraction, e.g. avoiding charge accumulation
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• CPC Class Codes: B81B 3/0013 Structures dimensioned for mechanical prevention of stiction, e.g. spring with increased stiffness
• CPC Class Codes: B81C 1/0015 Cantilevers switches using MEMS H01H1/0036; electrostatic relays using micromechanics H01H59/0009; microelectro-mechanical resonators H03H9/02244
• CPC Class Codes: H01G 5/18 due to change in inclination, e.g. by flexing, by spiral wrapping

Abstract

Micro-Electro-Mechanical System (MEMS) structures, methods of manufacture and design structures are disclosed. The method includes forming at least one fixed electrode on a substrate. The method further includes forming a Micro-Electro-Mechanical System (MEMS) beam with a varying width dimension, as viewed from a top of the MEMS beam, over the at least one fixed electrode.

Claims

1. A method comprising:

forming at least one fixed electrode on a substrate; and

forming a Micro-Electro-Mechanical System (MEMS) beam with a varying width dimension, as viewed from a top of the MEMS beam, over the at least one fixed electrode.

2. The method of claim 1, wherein forming the varying width dimension comprises:

forming a first portion with a constant width and a second portion with a reduced area.

3. The method of claim 2, wherein the second portion is formed at an initial pull-in portion of the MEMS beam.

4. The method of claim 3, wherein the initial pull-in portion of the MEMS beam is formed as one of:

a tapered end portion of a cantilever MEMS beam; and

a tapered midsection portion of a bridge MEMS beam.

5. The method of claim 3, further comprising forming actuator bumps extending from a surface of the MEMS beam toward the at least one fixed electrode.

6. The method of claim 5, wherein the actuator bumps are of varying height, with a height of an actuator bump at the initial pull-in portion of the MEMS beam being larger than a height of an actuator bump at another portion of the MEMS beam.

7. The method of claim 5, further comprising forming at least one trench in a substrate and between two of the fixed electrodes and aligned with at least one of the actuator bumps remote from the initial pull-in portion of the MEMS beam.

8. The method of claim 3, wherein the initial pull-in portion is formed with a constant width which is smaller than the constant width of the first portion.

9. The method of claim 8, wherein the initial pull-in portion of the MEMS beam is formed as one of:

an end portion of a cantilever MEMS beam; and

a midsection portion of a bridge MEMS beam.

10. The method of claim 8, further comprising forming actuator bumps extending from a surface of the MEMS beam toward the at least one fixed actuator.

11. The method of claim 10, wherein the actuator bumps are of varying height, with a height of an actuator bump at the initial pull-in portion of the MEMS beam being larger than a height of an actuator bump at another portion of the MEMS beam.

12. The method of claim 10, further comprising forming at least one trench in a substrate and between two of the fixed electrodes and aligned with at least one of the actuator bumps remote from the initial pull-in portion of the MEMS beam.

13. The method of claim 1, wherein forming the varying width dimension comprises:

forming a first portion with a constant width dimension;

forming a second portion with a tapered width dimension; and

forming a third portion with a constant width dimension which is smaller than the constant width dimension of the first portion,

wherein third portion is formed at an initial pull-in portion of the MEMS beam.

14. The method of claim 13, wherein the initial pull-in portion of the MEMS beam is formed as one of:

an end portion of a cantilever MEMS beam; and

a midsection portion of a bridge MEMS beam.

15. The method of claim 13, further comprising forming actuator bumps extending from a surface of the MEMS beam toward the at least one fixed actuator, wherein the actuator bumps are of varying height, with a height of an actuator bump at the initial pull-in portion of the MEMS beam being larger than a height of an actuator bump at another portion of the MEMS beam.

16. The method of claim 15, further comprising forming at least one trench in a substrate and between two of the fixed electrodes and aligned with at least one of the actuator bumps remote from the initial pull-in portion of the MEMS beam.

17. A method of forming a MEMS varactor, comprising:

forming a fixed electrode layer on a substrate through deposition and patterning;

forming a sacrificial material over the fixed electrode;

layering metal and insulator materials over the sacrificial material;

masking the layered metal and insulator materials with a varying width dimension;

etching the layered metal and insulator materials to form a beam structure with a non-uniformed width dimension, the non-uniform width dimension includes a reduced area portion of an initial pull-in section of the beam; and

forming a cavity about the beam through a venting process.

18. The method of claim 17, further comprising forming a plurality of actuator bumps comprising insulator material, extending from a surface of the beam and towards the fixed electrode layer and being of varying height.

19. The method of claim 18, further comprising forming at least one trench between two of the fixed electrodes and aligned with at least one of the plurality of actuator bumps.

20. The method of claim 17, further comprising forming a plurality of bumpers comprising insulator material, extending from a surface plane of the fixed electrode layer and towards the beam.

21. A structure comprising:

fixed electrodes formed on a substrate;

a composite beam structure having a varying width dimension with at least a first portion of a constant dimension and a second portion of a reduced width compared to the first portion, the second portion comprising an initial pull-in portion of the beam structure; and

a cavity structure surrounding the beam structure.

22. A method in a computer-aided design system for generating a functional design model of a MEMS structure, the method comprising:

generating a functional representation of a fixed electrodes formed on a substrate;

generating a functional representation of a composite beam structure having a varying width dimension with at least a first portion of a constant dimension and a second portion of a reduced width compared to the first portion, the second portion comprising an initial pull-in portion of the beam structure; and

generating a functional representation of a cavity structure surrounding the beam structure.