# US 10,246,319 B2 · Planar cavity MEMS and related structures, methods of manufacture and design structures

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- Number: US 10,246,319 B2
- Document ID: US10246319B2
- Status: Granted
- Kind: B2
- Application number: 15/802,801
- Filed: 2017-11-03
- Published: 2018-03-15
- Granted: 2019-04-02
- Earliest claimed: 2010-06-25
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Christopher V. Jahnes; Anthony K. Stamper
- Web page: https://patentgrep.com/patent/US10246319B2

## CPC

- B81C 1/00666: {Treatments for controlling internal stress or strain in MEMS structures}
- B81C 1/0015: {Cantilevers (switches using MEMS H01H1/0036; electrostatic relays using micromechanics H01H59/0009; microelectro-mechanical resonators H03H9/02244)}
- B81C 1/00365: {having low tensile stress between layers}
- B81C 1/00476: {removing a sacrificial layer (B81C1/00912 takes precedence)}
- B81C 1/00619: {Forming high aspect ratio structures having deep steep walls}
- B81C 1/00626: {Processes for achieving a desired geometry not provided for in groups B81C1/00563 - B81C1/00619}
- G06F 30/39: Circuit design at the physical level (physical level design for reconfigurable circuits G06F30/347)
- H01H 1/0036: {Switches making use of microelectromechanical systems [MEMS] (for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009)}
- H01H 57/00: Electrostrictive relays; Piezoelectric relays
- H10N 30/306: {Cantilevers}
- B81B 2201/014: having a cantilever fixed on one side connected to one or more dimples
- B81B 2203/0118: Cantilevers
- B81B 2203/04: Electrodes
- B81C 2201/0109: Sacrificial layers not provided for in B81C2201/0107 - B81C2201/0108
- B81C 2201/013: Etching
- B81C 2201/0167: by adding further layers of materials having complementary strains, i.e. compressive or tensile strain
- B81C 2201/017: Methods for controlling internal stress of deposited layers not provided for in B81C2201/0164 - B81C2201/0169
- B81C 2203/0136: Growing or depositing of a covering layer
- B81C 2203/0172: Seals
- G06F 2115/04: Micro electro-mechanical systems [MEMS]
- H01H 2057/006: {Micromechanical piezoelectric relay}
- Y10S 438/937: Hillock prevention
- Y10T 29/42: Piezoelectric device making
- Y10T 29/435: Solid dielectric type
- Y10T 29/49002: Electrical device making
- Y10T 29/49105: Switch making
- Y10T 29/49121: Beam lead frame or beam lead device
- Y10T 29/49126: Assembling bases
- Y10T 29/4913: Assembling to base an electrical component, e.g., capacitor, etc.
- Y10T 29/49155: Manufacturing circuit on or in base
- Y10T 29/5313: Means to assemble electrical device
- B81C: PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS (making microcapsules or microballoons B01J13/02; processes or apparatus specially adapted for the manufacture or treatment of piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/01)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## 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

### Claim 1

A Micro-Electro-Mechanical System (MEMS) structure comprising:
a moveable beam comprising at least one insulator layer on a lower electrode; and
an upper electrode over the at least one insulator layer,
wherein the lower electrode has a slotted layout to match a metal volume of the lower electrode with a metal volume of the upper electrode.

### Claim 2 (depends on 1)

The MEMS structure of claim 1, wherein the metal volume of the lower electrode and the metal volume of the upper electrode are based at least on a layout of the upper electrode.

### Claim 3 (depends on 2)

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

### Claim 4 (depends on 2)

The MEMS structure of claim 2, wherein the lower electrode and the upper electrode have identical layouts and same thicknesses.

### Claim 5 (depends on 1)

The MEMS structure of claim 1, 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.

### Claim 6 (depends on 1)

The MEMS structure of claim 1, wherein the lower electrode is in a trench.

### Claim 7 (depends on 1)

The MEMS structure of claim 1, wherein the lower electrode and the upper electrode are composed of Ti/AlCu/Ti/TiN.

### Claim 8 (depends on 1)

The MEMS structure of claim 1, wherein the upper electrode is U-shaped with a via between opposing sides of the upper electrode.

### Claim 9 (depends on 1)

The MEMS structure of claim 1, wherein the lower electrode and the upper electrode are asymmetric relative to one another.

### Claim 10 (depends on 1)

The MEMS structure of claim 1, wherein the upper electrode is thinned compared to the lower electrode to match the metal volume of the upper electrode with the metal volume of the lower electrode.

### Claim 11 (depends on 1)

The MEMS structure of claim 1, wherein the modified beam bending characteristics of the moveable beam are provided over an entire temperature range including a lower limit of about −55° C. to an upper limit of about 125° C.

### Claim 12 (depends on 1)

The MEMS structure of claim 1, wherein the metal volume of the lower electrode is adjusted to modify beam bending characteristics.

### Claim 13 (depends on 1)

The MEMS structure of claim 1, wherein the at least one insulator layer is on a top surface of the lower electrode.

### Claim 14 (depends on 1)

The MEMS structure of claim 1, wherein the upper electrode is U-shaped with a tungsten stud via between sides of the upper electrode.

### Claim 15 (depends on 1)

The MEMS structure of claim 1, wherein a coefficient of thermal expansion (CTE) of the lower electrode and the upper electrode is approximated by AlCu.

### Claim 16 (depends on 1)

The MEMS structure of claim 1, wherein a volume ratio of the metal volume of the lower electrode to the metal volume of the upper electrode comprises 0.93:1.