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

• US 9,932,222 B2
• Filed: 05/24/2016
• Issued: 04/03/2018
• Est. Priority Date: 04/12/2013
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Brigham, Michael T., Jahnes, Christopher V., Luce, Cameron E., Maling, Jeffrey C., Murphy, William J., Stamper, Anthony K., White, Eric J.
• Primary Examiner(s): Feeney, Brett
• Assistant Examiner(s): Peterson, Erik T
• Application Number:
  US15/162,994
• Publication Number:
  US 20160264406A1
• Time in Patent Office: 679 Days
• Field of Search: None
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81B 2203/0315 Cavities
• CPC Class Codes: B81B 2207/09 Packages
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: B81C 1/00047 Cavities
• 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: B81C 1/00269 Bonding of solid lids or wafers to the substrate
• CPC Class Codes: B81C 1/00365 having low tensile stress between layers
• CPC Class Codes: B81C 1/00531 Dry etching
• CPC Class Codes: B81C 1/00936 Releasing the movable structure without liquid etchant
• CPC Class Codes: B81C 2201/0104 Chemical-mechanical polishing [CMP]
• CPC Class Codes: B81C 2201/0107 Sacrificial metal
• CPC Class Codes: B81C 2201/0121 involving addition of material followed by removal of parts of said material, i.e. subtractive planarization
• CPC Class Codes: B81C 2201/0125 Blanket removal, e.g. polishing
• CPC Class Codes: B81C 2201/0132 Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling
• CPC Class Codes: B81C 2201/0176 Chemical vapour Deposition
• CPC Class Codes: B81C 2201/0181 Physical Vapour Deposition [PVD], i.e. evaporation, sputtering, ion plating or plasma assisted deposition, ion cluster beam technology
• CPC Class Codes: B81C 2203/0109 Bonding an individual cap on the substrate
• CPC Class Codes: B81C 2203/0145 Hermetically sealing an opening in the lid
• CPC Class Codes: B81C 2203/0714 Forming the micromechanical structure with a CMOS process
• CPC Class Codes: G06F 30/20 : Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30

Abstract

Micro-Electro-Mechanical System (MEMS) structures, methods of manufacture and design structures are disclosed. The method includes forming a Micro-Electro-Mechanical System (MEMS) beam structure by venting both tungsten material and silicon material above and below the MEMS beam to form an upper cavity above the MEMS beam and a lower cavity structure below the MEMS beam.

Claims

1. A method comprising:

forming a Micro-Electro-Mechanical System (MEMS) beam structure comprising;

forming both tungsten material and semiconductor material on a substrate;

forming the MEMS beam structure above the tungsten material and the semiconductor material;

forming both the tungsten material and the semiconductor material above the MEMS beam structure;

forming a lid over the tungsten material formed above the MEMS beam structure;

forming at least one vent hole in the lid and through the tungsten material formed above the MEMS beam structure to expose the semiconductor material formed above the MEMS beam structure; and

etching the semiconductor material formed above the MEMS beam structure while etching the tungsten material formed above the MEMS beam structure to form an upper cavity structure above the MEMS beam structure and below the lid; and

etching both the tungsten material and the semiconductor material below the MEMS beam structure to form a lower cavity structure above the substrate and below the MEMS beam structure,

wherein the MEMS beam structure comprises a cantilevered beam structure, and

wherein the etching comprises performing an XeF₂ etching process.

2. The method of claim 1, wherein the etching and film thicknesses are controlled to ensure that all or substantially all of the tungsten material is removed above the MEMS beam structure, prior to the semiconductor material above the MEMS beam structure.

3. The method of claim 1, wherein the semiconductor material is one of silicon material and germanium material.

4. The method of claim 3, wherein the semiconductor material is silicon material, and wherein the tungsten material and silicon material below the MEMS beam structure comprises forming the tungsten material on a substrate and forming the silicon material over the tungsten material.

5. The method of claim 4, wherein the tungsten material and silicon material above the MEMS beam structure comprises forming the silicon material within a via in contact with the silicon material below the MEMS beam structure and forming the tungsten material over the silicon material.

6. The method of claim 5, wherein the etching comprising forming a vent hole in the lid to expose at least the silicon material above the MEMS beam structure.

7. The method of claim 5, wherein the tungsten material at least one of above and below the MEMS beam structure is formed by a physical vapor deposition process followed by a chemical vapor deposition process.

8. The method of claim 5, further comprising forming an additional silicon material on the tungsten material above the MEMS beam structure.

9. The method of claim 8, further comprising:

planarizing the additional silicon material;

forming the lid over the planarized additional silicon material;

forming at least one venting hole in the lid, exposing the additional silicon material; and

etching the tungsten material, silicon material and additional silicon material above and below the MEMS beam structure to form the upper cavity and the lower cavity.

10. The method of claim 1, wherein the lid is formed with a planar surface on an underside thereof by depositing the lid directly on one of the tungsten material formed over the MEMS beam structure or another layer of semiconductor material formed on the tungsten material formed over the MEMS beam structure.

11. The method of claim 1, wherein the forming of the least one vent hole is forming at least two vent holes, wherein a first of the at least two vent holes exposes the semiconductor material above the MEMS beam structure and a second of the at least two vent holes exposes the tungsten material above the MEMS beam structure.

12. A method comprising forming a Micro-Electro-Mechanical System (MEMS) beam structure by etching both tungsten material and semiconductor material at least above and below the MEMS beam structure, formed above a substrate, to form an upper cavity structure above the MEMS beam structure and a lower cavity structure above the substrate and below the MEMS beam structure, wherein the MEMS beam structure comprises a cantilevered beam structure,

further comprising:

forming a lid over the tungsten material formed above the MEMS beam structure;

forming at least one vent hole in the lid and through the tungsten material formed above the MEMS beam structure to expose the semiconductor material formed above the MEMS beam structure; and

etching the semiconductor material formed above the MEMS beam structure while etching the tungsten material formed above the MEMS beam structure to form the lower cavity structure above the MEMS beam structure and below the lid,

wherein the etching comprises performing an XeF₂ etching process.

13. The method of claim 12, wherein the lid is formed with a planar surface on an underside thereof by depositing the lid directly on one of the tungsten material formed over the MEMS beam structure or another layer of semiconductor material formed on the tungsten material formed over the MEMS beam structure.

14. The method of claim 12, wherein the forming of the at least one vent hole is forming at least two vent holes, wherein a first of the at least two vent holes exposes the semiconductor material above the MEMS beam structure and a second of the at least two vent holes exposes the tungsten material above the MEMS beam structure.

15. The method of claim 12, wherein the etching and film thicknesses are controlled to ensure that all or substantially all of the tungsten material is removed above the MEMS beam structure, prior to the semiconductor material above the MEMS beam structure.

16. The method of claim 12, wherein the semiconductor material is one of silicon material and germanium material.

17. The method of claim 16, wherein the semiconductor material is silicon material, and wherein the tungsten material and silicon material below the MEMS beam structure comprises forming the tungsten material on a substrate and forming the silicon material over the tungsten material.

18. The method of claim 17, wherein the tungsten material and silicon material above the MEMS beam structure comprises forming the silicon material within a via in contact with the silicon material below the MEMS beam structure and forming the tungsten material over the silicon material.