Microactuators including a metal layer on distal portions of an arched beam

• US 6,255,757 B1
• Filed: 09/01/1999
• Issued: 07/03/2001
• Est. Priority Date: 09/01/1999
• Status: Expired due to Term

• Current Assignee: Memscap Incorporated
• Original Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Inventors: Dhuler, Vijayakumar R., Walters, Mark David
• Primary Examiner(s): Ramirez, Nestor
• Assistant Examiner(s): LE, DANG D
• Application Number:
  US09/388,321
• Time in Patent Office: 671 Days
• Field of Search: 310/306, 310/307, 310/328, 310/330, 310/331, 310/343, 310/348, 310/365, 310/356, 251/129.02, 251/129.01, 251/129.03
• US Class Current: 310/307
• CPC Class Codes: B81B 2201/031 Thermal actuators
• CPC Class Codes: B81B 2201/054 Microvalves
• CPC Class Codes: B81B 2203/0109 Bridges
• CPC Class Codes: B81B 2203/051 Translation according to an axis parallel to the substrate
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60
• CPC Class Codes: B81C 2203/031 Anodic bondings
• CPC Class Codes: B81C 2203/036 Fusion bonding
• CPC Class Codes: F15C 5/00 Manufacture of fluid circuit elements; Manufacture of assemblages of such elements integrated circuits
• CPC Class Codes: F16K 2099/0074 using photolithography, e.g. etching
• CPC Class Codes: F16K 2099/008 Multi-layer fabrications
• CPC Class Codes: F16K 99/0001 Microvalves microdevices B81B1/00; manufacture or treatment of devices or systems in or on a substrate B81C1/00; microfluidic structures B01L3/5027; micropumps F04B19/006
• CPC Class Codes: F16K 99/0007 of cantilever type
• CPC Class Codes: F16K 99/0009 the valve element held by multiple arms
• CPC Class Codes: F16K 99/0011 Gate valves or sliding valves
• CPC Class Codes: F16K 99/0036 operated by temperature variations
• CPC Class Codes: H01H 2001/0042 Bistable switches, i.e. having two stable positions requiring only actuating energy for switching between them, e.g. with snap membrane or by permanent magnet

Abstract

A microelectromechanical (MEMS) device is provided that includes a microelectronic substrate and a thermally actuated microactuator and associated components disposed on the substrate and formed as a unitary structure from a single crystalline material, wherein the associated components arc actuated by the microactuator upon thermal actuation thereof. For example, the MEMS device may be a valve. As such, the valve may include at least one valve plate that is controllably brought into engagement with at least one valve opening in the microelectronic substrate by selective actuation of the microactuator. While the MEMS device can include various microactuators, the microactuator advantageously includes a pair of spaced apart supports disposed on the substrate and at least one arched beam extending therebetween. By heating the at least one arched beam of the microactuator, the arched beams will further arch such that the microactuator moves between a closed position in which the valve plate sealingly engages the valve opening and an open position in which the valve plate is at least partly disengaged from and does not seal the valve opening. The microactuator may further include metallization traces on distal portions of the arched beams to constrain the thermally actuated regions of arched beams to medial portions thereof. The valve may also include a latch for maintaining the valve plate in a desired position without requiring continuous energy input to the microactuator. An advantageous method for fabricating a MEMS valve having unitary structure single crystalline components is also provided.

Claims

1. A microactuator comprising:

a microelectronic substrate;

spaced apart supports disposed upon said microelectronic substrate;

at least one arched beam comprising a semiconductor material and extending between said spaced apart supports, the arched beam having opposed distal portions proximate the respective supports and an arched medial portion extending between the distal portions; and

a metal layer disposed on the distal portions of said at least one arched beam, wherein the arched medial portion of the arched beam is substantially free of said metal layer such that an electrical current passing between said supports preferentially heats the arched medial portion of the arched beam and causes further arching of the arched medial portion of the arched beam.

2. A microactuator according to claim 1 further including an actuator member operably coupled to said at least one arched beam and extending outwardly therefrom.

3. A microactuator according to claim 1 wherein said at least one arched beam is comprised of single crystalline silicon.

4. A microactuator according to claim 1 wherein the metal layer is comprised of at least one of nickel, gold, and platinum.

5. A microactuator according to claim 1, wherein the medial portion is suspended over a portion of the microelectronic substrate.