PLANAR CAVITY MEMS AND RELATED STRUCTURES, METHODS OF MANUFACTURE AND DESIGN STRUCTURES

• US 20110315526A1
• Filed: 12/20/2010
• Published: 12/29/2011
• Est. Priority Date: 06/25/2010
• 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 8,709,264 B2
• Time in Patent Office: Days
• US Class Current: 200/181
• CPC Class Codes: B81B 2201/014 having a cantilever fixed on one side connected to one or more dimples
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81B 2203/04 Electrodes
• 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 1/00365 having low tensile stress between layers
• CPC Class Codes: B81C 1/00476 removing a sacrificial layer B81C1/00912 takes precedence
• CPC Class Codes: B81C 1/00619 Forming high aspect ratio structures having deep steep walls
• CPC Class Codes: B81C 1/00626 Processes for achieving a desired geometry not provided for in groups B81C1/00563 - B81C1/00619
• CPC Class Codes: B81C 1/00666 Treatments for controlling internal stress or strain in MEMS structures
• CPC Class Codes: B81C 2201/0109 Sacrificial layers not provided for in B81C2201/0107 - B81C2201/0108
• CPC Class Codes: B81C 2201/013 Etching
• CPC Class Codes: B81C 2201/0167 by adding further layers of materials having complementary strains, i.e. compressive or tensile strain
• CPC Class Codes: B81C 2201/017 Methods for controlling internal stress of deposited layers not provided for in B81C2201/0164 - B81C2201/0169
• CPC Class Codes: B81C 2203/0136 Growing or depositing of a covering layer
• CPC Class Codes: B81C 2203/0172 Seals
• CPC Class Codes: G06F 2115/04 Micro electro-mechanical systems [MEMS]
• CPC Class Codes: G06F 30/39 Circuit design at the physical level physical level design for reconfigurable circuits G06F30/347
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H01H 2057/006 Micromechanical piezoelectric relay
• CPC Class Codes: H01H 57/00 Electrostrictive relays; Piezoelectric relays
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H10N 30/306 : Cantilevers
• CPC Class Codes: Y10S 438/937 : Hillock prevention
• CPC Class Codes: Y10T 29/42 : Piezoelectric device making
• CPC Class Codes: Y10T 29/435 : Solid dielectric type
• CPC Class Codes: Y10T 29/49002 : Electrical device making
• CPC Class Codes: Y10T 29/49105 : Switch making
• CPC Class Codes: Y10T 29/49121 : Beam lead frame or beam lead device
• CPC Class Codes: Y10T 29/49126 : Assembling bases
• CPC Class Codes: Y10T 29/4913 : Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49155 : Manufacturing circuit on or in base
• CPC Class Codes: Y10T 29/5313 : Means to assemble electrical device

Abstract

A method of forming a Micro-Electro-Mechanical System (MEMS) includes forming a lower electrode on a first insulator layer within a cavity of the MEMS. The method further includes forming an upper electrode over another insulator material on top of the lower electrode which is at least partially in contact with the lower electrode. The forming of the lower electrode and the upper electrode includes adjusting a metal volume of the lower electrode and the upper electrode to modify beam bending.

Claims

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

forming a lower electrode on a sacrificial layer;

forming an insulator layer on the lower electrode; and

forming an upper electrode over the insulator material on top of the lower electrode, the upper electrode being at least partially in contact with the lower electrode,

wherein the forming of the lower electrode and the upper electrode includes adjusting a metal volume of the lower electrode and the upper electrode to modify beam bending.

2. The method of claim 1, wherein the lower electrode and the upper electrode are formed of a same material.

3. The method of claim 2, wherein the lower electrode and the upper electrode are composed of Ti/AlCu/Ti/TiN.

4. The method of claim 3, wherein a coefficient of thermal expansion (CTE) of the lower electrode and the upper electrode is approximated by the AlCu.

5. The method of claim 1, wherein the metal volume is determined by a thickness of aluminum and copper and layout of the lower electrode and the upper electrode.

6. The method of claim 5, wherein the forming of the lower electrode and the upper electrode includes forming identical layouts for the lower electrode and the upper electrode, with a same thicknesses.

7. The method of claim 1, wherein one of the lower electrode and the upper electrode is formed as a slotted or holed layout and one of the upper electrode and the lower electrode, respectively, is thinned with respect to a thickness of the slotted or holed layout, to match the metal volume.

8. The method of claim 1, further comprising adjusting a thickness of the lower electrode to adjust a stress gradient thereby causing the lower electrode to deflect up or down post release, or to change bending induced by changing temperature.

9. The method of claim 1, wherein the lower electrode and the upper electrode are asymmetric or different, and a thickness of one of the lower electrode and the upper electrode with a lower pattern factor is thickened to balance the metal volume.

10. The method of claim 1, wherein at least one of the lower electrode and the upper electrode is formed with patterned shapes to decrease a likelihood of metal hillocks formation.

11. The method of claim 1, wherein the lower electrode has a percentage less area than the upper electrode, and the lower electrode is thickened by a percentage to rebalance the metal volume.

12. The method of claim 1, wherein a pattern factor ratio of the lower electrode to the upper electrode comprises 0.8:

1, and a volume ratio of the lower electrode to the upper electrode comprises 0.93;

1.

13. A method of forming a switch, comprising forming a moveable beam comprising at least one insulator layer on a conductor layer such that a volume of the conductor is adjusted to modify beam bending characteristics.

14. The method of claim 13, wherein the moveable beam is formed from one or more metal layers, comprising a top metal and a bottom metal with an oxide layer therebetween.

15. The method of claim 14, further comprising varying a metal volume of the top metal and the bottom metal by changing a thickness of at least one of the metal layers.

16. The method of claim 15, wherein the varying comprises changing a layout of at least one of the metal layers.

17. The method of claim 13, wherein the modify beam bending characteristics is provided over a temperature range of about −

55°

C. to 125°

C.

18. A method, comprising:

forming a lower electrode; and

forming an upper electrode on top of the lower electrode,

wherein the forming of the lower electrode and the upper electrode includes balancing a metal volume of the lower electrode with respect to the upper electrode.

19. The method of claim 18, wherein:

the lower electrode and the upper electrode are formed of a same material; and

metal volume is determined by metal thickness and layout of the lower electrode and the upper electrode.

20. The method of claim 18, wherein one of the lower electrode and the upper electrode comprises a slotted or holed layout and one of the upper electrode and the lower electrode, respectively, is thinned with respect to the slotted or holed layout, to match the metal volume.

21. The method of claim 18, further comprising adjusting a thickness of the lower electrode to adjust a stress gradient causing the lower electrode to deflect up or down post release, or to change bending induced by changing temperature.

22. The method of claim 18, wherein the lower electrode and the upper electrode are asymmetric or different, and a thickness of one of the lower electrode and the upper electrode with a lower pattern factor is thickened to balance the metal volume.

23. The method of claim 18, further comprising forming a dielectric layer at least one of over a fixed wiring or under the lower electrode to form a capacitor.

24. A MEMS structure comprising a moveable beam comprising at least one insulator layer on a conductor layer such that a volume of the conductor is adjusted to modify beam bending characteristics.

25. A design structure readable by a machine used in design, manufacture, or simulation of an integrated circuit, the design structure comprising a moveable beam comprising at least one insulator layer on a conductor layer such that a volume of the conductor is adjusted to modify beam bending characteristics.