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

• US 20140308771A1
• Filed: 04/12/2013
• Published: 10/16/2014
• 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.
• Granted Patent: US 9,969,613 B2
• Time in Patent Office: Days
• US Class Current: 438/51
• 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 by venting both tungsten material and semiconductor material at least above and below the MEMS beam to form an upper cavity structure above the MEMS beam and a lower cavity structure below the MEMS beam.

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

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 tungsten material and silicon material below the MEMS beam 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 comprises forming the silicon material within a via in contact with the silicon material below the MEMS beam and forming the tungsten material over the silicon material.

6. The method of claim 5, wherein the venting comprising forming a vent hole to expose at least the silicon material above the MEMS beam and performing an XeF₂ etching process.

7. The method of claim 6, wherein the tungsten material at least one of above and below the MEMS beam is formed by a physical vapor deposition process followed by a chemical vapor deposition process.

8. The method of claim 6, further comprising forming an additional silicon material on the tungsten material above the MEMS beam.

9. The method of claim 8, further comprising:

planarizing the additional silicon material;

forming a lid over the planarized additional silicon material;

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

venting the materials above and below the MEMS beam to form the upper cavity and the lower cavity.

10. The method of claim 1, further comprising:

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

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

venting the semiconductor material formed above the MEMS beam while venting the tungsten material formed above the MEMS beam.

11. The method of claim 10, 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 or another layer of semiconductor material formed on the tungsten material formed over the MEMS beam.

12. The method of claim 10, 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 and a second of the at least two vent holes exposes the tungsten material above the MEMS beam.

13. The method of claim 1, wherein the tungsten material above the MEMS beam is formed in seams formed in the semiconductor material above the MEMS beam, and the venting begins with the semiconductor material above the MEMS beams.

14. The method of claim 1, wherein the venting forms an undercut in at least one of the upper cavity and the lower cavity.

15. The method of claim 1, wherein the tungsten material at least one of above and below the MEMS beam is devoid of oxide.

16. A method of forming a Micro-Electro-Mechanical System (MEMS) beam, comprising:

forming a wiring layer on a substrate;

forming a first tungsten material over the substrate;

forming a first silicon material over the first tungsten material;

forming a MEMS beam over the first silicon material;

forming a via through the MEMS beam to expose the first silicon material;

forming a second silicon material above the MEMS beam and within the via to contact exposed portions of the first silicon material;

forming second tungsten material on the second silicon material;

forming a lid over the second tungsten material;

forming at least one vent hole in the lid, exposing a portion of the at least second silicon material;

venting the first and second tungsten material and the first and second silicon material to form a lower cavity and an upper cavity about the MEMS beam, respectively; and

sealing the at least one vent hole.

17. The method of claim 16, further comprising forming the second tungsten material in seams formed in the second silicon material, and planarizing the second silicon material.

18. The method of claim 16, further comprising forming a third silicon material on the second tungsten material, and forming the lid directly on the third silicon material.

19. A structure, comprising a cavity structure with tungsten material extruding within the cavity and a recess formed by removal of silicon material through a venting process.

20. A method in a computer-aided design system for generating a functional design model of a MEMS structure which is embodied on tangible readable medium and when executed on a computing device comprises:

generating a functional representation of a MEMS beam having at least one via extending therethrough;

generating a functional representation of a layered structure below the MEMS beam comprising a layer of tungsten material formed below a layer of silicon material;

generating a functional representation of a layered structure above the MEMS beam comprising a layer of silicon material within the at least one via in contact with the silicon material below the MEMS beam, and a tungsten material thereabove;

generating a functional representation of a lid formed over the layered structure above the MEMS beam; and

generating a functional representation of a lower cavity and an upper cavity, formed by venting the layered structures through at least one vent hole in the lid.