Bimorph MEMS devices

• US 7,084,554 B2
• Filed: 12/20/2004
• Issued: 08/01/2006
• Est. Priority Date: 02/25/2003
• Status: Expired due to Fees

• Current Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Wong, William S., Xu, Baomin
• Primary Examiner(s): BUDD, MARK OSBORNE
• Application Number:
  US11/017,498
• Publication Number:
  US 20050104478A1
• Time in Patent Office: 589 Days
• Field of Search: 310/324, 310/328, 310330-332, 310/358
• US Class Current: 310/332
• CPC Class Codes: B81B 2201/032 Bimorph and unimorph actuators, e.g. piezo and thermo
• CPC Class Codes: B81B 3/0024 Transducers for transforming thermal into mechanical energy or vice versa, e.g. thermal or bimorph actuators electric motors using thermal effects H02N10/00
• CPC Class Codes: H10N 30/01 Manufacture or treatment
• CPC Class Codes: H10N 30/073 by fusion of metals or by adhesives
• CPC Class Codes: H10N 30/074 by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing
• CPC Class Codes: H10N 30/086 by polishing or grinding
• CPC Class Codes: H10N 30/2042 Cantilevers, i.e. having one fixed end
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/49126 Assembling bases
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49147 Assembling terminal to base
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base
• CPC Class Codes: Y10T 29/49156 with selective destruction of conductive paths

Abstract

A micro-electromechanical dimensioned bimorph structure includes a first element layer structure, and a second element layer structure. The element layer structures are provided in various combinations, including piezoelectric/piezoelectric, antiferroelectric/antiferroelectric or antiferroelectric/piezoelectric. The layer thickness of the element structure is less than 100 μm. A bonding layer bonds the first element structure directly to the second element structure, and the bonding layer thickness is less than 10 μm. The bimorph structure can be made in various forms including a cantilever or a diaphragm. Microfluidic devices using the bimorph structures may also be constructed.

Claims

1. A microelectro-mechanical dimensioned bimorph structure comprising:

a first MEMS sized deposited morphable element structure, made by a deposition process on a first substrate;

a second MEMS sized deposited morphable element structure, made by a deposition process on a second substrate; and

a bonding layer bonding the first element structure directly to the second element structure, the bonding layer being less than 10 μ

m in thickness and comprised of one of a nonconductive epoxy bonding material containing conductive particles, or nonconductive epoxy bonding material alone, both of which are ineffective for their intended purpose at temperatures reached in the preparation process used to make the deposited morphable element structure,

wherein the bimorph structure is physically separate and apart from the first and second substrates on which the first element structure and the second element structure were deposited and formed respectively.

2. The structure according to claim 1, wherein the bonding layer is about 1 μ

m or less in thickness.

3. The structure according to claim 1, wherein the first and second element structure each have a thickness of 100 μ

m or less.

4. The structure according to claim 1, wherein one of the first element or the second element is further bonded to a target substrate or system, and wherein the target substrate or system is comprised of a material which will cause the target substrate or system to be destroyed and rendered inoperative at an annealing or sintering temperature of the first or second element.

5. The structure according to claim 4, wherein the target system is at least one of a fluidic reservoir or ink cavity body with a nozzle plate.

6. The structure according to claim 1, wherein the first element and the second element are each made from antiferroelectric material.

7. The structure according to claim 6, wherein the first element is connected to a driving circuit, and the second element is separately connected to the driving circuit, wherein actuation of the first element and the second element are independent of each other.

8. The structure according to claim 1, wherein the first element and the second element are each made from piezoelectric material.

9. The structure according to claim 1, wherein the first element is made from an antiferroelectric material and the second element is made from a piezoelectric material.

10. The structure according to claim 1, wherein the structure is in the form of a cantilever, with one or both ends bonded or secured to a substrate.

11. The structure according to claim 1, wherein the structure is in the form of a diaphragm, with the perimeter of the diaphragm bonded or secured to a target substrate.

16. The structure according to claim 4, wherein the target substrate includes at least one of a plastic or a metal foil.

19. The structure according to claim 1, wherein the bonding materials are nonconductive epoxy bonding materials containing conductive particles.

20. The structure according to claim 1, wherein the bonding materials are the nonconductive epoxy bonding materials alone.

21. The structure according to claim 1, wherein the target system is at least one of a fluidic reservoir or ink cavity body with a nozzle plate.

22. The structure according to claim 1, wherein the piezoelectric or antiferroelectric film is a polycrystalline ceramic.

12. A microfluidic ejector comprising:

a nozzle plate;

a fluidic cavity body bonded to the nozzle plate; and

a MEMS sized diaphragm bimorph actuator structure bonded to the cavity body, wherein the diaphragm bimorph actuator structure is configured from two layers of at least one of a sintered or annealed piezoelectric film and a sintered or annealed antiferroelectric film, and a structure bonding layer which bonds the sintered or annealed piezoelectric film or the sintered or annealed antiferroelectric film, the bonding layer comprised of at least one of a nonconductive epoxy bonding material with conductive particles or a nonconductive epoxy bonding material alone, both of which are ineffective for their intended purpose at temperatures required for generating either of the sintered or annealed piezoelectric film or the sintered or annealed antiferroelectric film,

wherein the two layers of the bimorph actuator structure are each made by a deposition process on respective first substrate and second substrates, and

wherein the microfluidic ejector is physically separate and apart from the first and second substrates on which the two layers were deposited and formed.

13. The microfluidic ejector according to claim 12, wherein the bimorph actuator structure is comprised of a piezoelectric/piezoelectric layer structure, with each piezoelectric layer thickness less than 100 μ

m.

14. The microfluidic ejector according to claim 12, wherein the bimorph actuator structure is comprised of an antiferroelectric/piezoelectric layer structure, with both the piezoelectric layer thickness and the antiferroelectric layer thickness less than 100 μ

m.

15. The microfluidic ejector according to claim 12, wherein the bimorph actuator structure is comprised of an antiferroelectric/antiferroelectric layer structure, with each antiferroelectric layer thickness less than 100 μ

m.

17. The microfluidic ejector of claim 12, wherein the fluidic cavity body is comprised of a material which would be destroyed at temperatures used for sintering or annealing the piezoelectric or antiferroelectric films.

18. The microfluidic ejector according to claim 12, wherein the fluidic cavity includes at least one of a plastic or a metal foil.

23. The structure according to claim 12, wherein the bonding materials are the nonconductive epoxy bonding materials containing conductive particles.

24. The structure according to claim 12, wherein the bonding materials are the nonconductive epoxy bonding materials alone.

25. The structure according to claim 12, wherein the piezoelectric or antiferroelectric film is a polycrystalline ceramic.