Methods to make piezoelectric ceramic thick film arrays and elements

• US 7,089,635 B2
• Filed: 02/25/2003
• Issued: 08/15/2006
• 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: Weisberg, Michael C., Buhler, Steven A., Fitch, John S., Wong, William S., Solberg, Scott E., Xu, Baomin, Littau, Karl A., Elrod, Scott A.
• Primary Examiner(s): TRINH, MINH N
• Application Number:
  US10/376,544
• Publication Number:
  US 20040164650A1
• Time in Patent Office: 1,267 Days
• Field of Search: 29/253.5, 29/254.2, 298/31, 298/46, 29D/IG.16, 294/23, 156/152, 156/247, 310/340, 310/365, 438/455, 438/458, 438/604, 438/107, 428/202, 428/209
• US Class Current: 29/25.35
• CPC Class Codes: B41J 2/161 of film type, deformed by bending and disposed on a diaphragm
• CPC Class Codes: B41J 2/1623 bonding and adhesion
• CPC Class Codes: B41J 2/1632 machining
• CPC Class Codes: B41J 2/1634 laser machining
• CPC Class Codes: B41J 2/1637 molding
• CPC Class Codes: B41J 2/1646 thin film formation by sputtering
• CPC Class Codes: H01L 2221/68368 used in a transfer process involving at least two transfer steps, i.e. including an intermediate handle substrate
• 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 30/081 by coating or depositing using masks, e.g. lift-off
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/435 Solid dielectric type
• 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 29/49133 with component orienting
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base
• CPC Class Codes: Y10T 29/4981 Utilizing transitory attached element or associated separate material

Abstract

A method of producing at least one piezoelectric element includes depositing a piezoelectric ceramic material onto a surface of a first substrate to form at least one piezoelectric element structure. Then an electrode is deposited on a surface of the at least one piezoelectric element structure. Next, the at least one piezoelectric element structure is bonded to a second substrate, the second substrate being conductive or having a conductive layer. The first substrate is then removed from the at least one piezoelectric element structure and a second side electrode is deposited on a second surface of the at least one piezoelectric element structure. A poling operation is performed to provide the at least one piezoelectric element structure with piezoelectric characteristics.

Claims

1. A method of producing at least one piezoelectric element comprising:

depositing a piezoelectric ceramic material onto a first surface of at least one first substrate to form at least one piezoelectric element structure, having a first surface of the at least one piezoelectric element structure in direct contact with the first surface of the at least one first substrate;

depositing an electrode on a second surface of the at least one piezoelectric element structure;

bonding the at least one piezoelectric element structure to a transfer substrate, wherein the bond between the piezoelectric element structure and the transfer substrate is temporary;

removing the at least one first substrate from the at least one piezoelectric element structure;

depositing a second side electrode on a first surface of the at least one Piezoelectric element structure;

poling, by applying a DC voltage to the at least one piezoelectric element structure, to provide the at least one piezoelectric element structure with piezoelectric characteristics;

performing a property test following the poling step to determine the operational characteristics of the poled, at least one piezoelectric element structure on the transfer substrate;

bonding the tested piezoelectric element structure to a final target substrate or system; and

removing the transfer substrate from the tested at least one piezoelectric element structure.

3. The method according to claim 1, wherein the step of bonding the at least one piezoelectric element structure to the second substrate, includes the second substrate being a transfer substrate, wherein the bond is a temporary bond.

4. The method according to claim 3, further including,

bonding the at least one poled piezoelectric element structure with piezoelectric characteristics to a final target substrate, wherein the bond is permanent;

and

removing the transfer substrate from the at least one poled piezoelectric element structure.

5. The method according to claim 1, wherein the bonding step includes the use of a nonconductive epoxy alone, wherein electrical contact between the electrode and the second substrate is maintained.

6. The method according to claim 5, wherein the nonconductive epoxy is less than approximately 1 μ

m thick.

7. The method according to claim 5, wherein the electrical contact between the electrode and the second substrate is maintained by electrical contact points, formed when a surface of the electrode and the second substrate are moved into contact.

8. The method according to claim 1, wherein the bonding step includes the use of thin film intermetallic transient liquid phase bonding between the first side electrode and the second substrate.

9. The method according to claim 1, wherein the step of removing the first substrate is provided by a liftoff process including,

emitting, from a radiation source, a radiation beam through the first substrate to an attachment interface formed by the first substrate and the at least one piezoelectric element structure, wherein the first substrate is substantially transparent at the wavelength of the radiation beam, and the radiation beam generates sufficient energy at the interface to break the attachment.

10. The method according to claim 9, wherein the step of removing the first substrate further includes heating the interface with a heater to break any remaining attachment, wherein the heater is a different device from the radiation source.

11. The method according to claim 10, wherein the radiation source is a laser beam generated by a laser and the heater generates heat energy by a manner other than use of a laser beam.

12. The method according to claim 1, wherein the depositing step includes patterning the piezoelectric material.

13. The method according to claim 1, wherein the depositing step implements a direct marking process.

14. The method according to claim 13, wherein the direct marking process is at least one of screen printing, ballistic aerosol marking, jet printing and acoustic ejection.

15. The method according to claim 1, wherein the depositing step is performed in a way that a lattice matching between the first substrate and the deposited piezoelectric material is not required.

16. The method according to claim 1, wherein the depositing step includes sintering the at least one piezoelectric element structure at a temperature of above 600°

C.

17. The method according to claim 1, wherein a thickness of the at least one piezoelectric element structure is between 10μ

m to 100μ

m.

18. The method according to claim 1, wherein the at least one piezoelectric element structure is an array of element structures.

19. The method according to claim 1, further including, polishing a surface of the at least one piezoelectric element structure.

20. The method according to claim 19, wherein the polishing step is a dry tape polishing procedure.

21. The method according to claim 1, wherein the first substrate is reusable.

22. The method according to claim 1, wherein the first substrate is sapphire.

23. The method according to claim 1, wherein the depositing step includes sintering the at least one piezoelectric element structure at a temperature in a range of approximately 1100°

C. to 1350°

C.

24. The method according to claim 1, wherein the bonding step includes the use of a nonconductive epoxy bonding material containing conductive particles.

25. The method according to claim 1, wherein there are a plurality of first substrates, each of the first substrates being made of a same substrate material, and a plurality of piezoelectric elements each of the piezoelectric elements being made of a same piezoelectric material.

26. The method according to claim 1, wherein there are a plurality of first substrates, at least some of the first substrates being made of substrate materials different from each other, and a plurality of piezoelectric elements each being made of a same piezoelectric material.

27. The method according to claim 1, wherein there are a plurality of first substrates, each of the first substrates being made of a same substrate material, and a plurality of piezoelectric elements, at least some of the piezoelectric elements being made of piezoelectric materials different from each other.

28. The method according to claim 1, wherein there are a plurality of first substrates, at least some of the first substrates being made of substrate materials different from each other, and a plurality of piezoelectric elements, at least some of the piezoelectric elements being made of piezoelectric materials different from each other.

2. A method of producing at least one piezoelectric element comprising:

depositing a piezoelectric ceramic material onto a first surface of at least one first substrate to form at least one piezoelectric element structure, wherein a first surface of the piezoelectric ceramic material and the first surface of the first substrate are in direct contact;

depositing an electrode on a second surface of the at least one piezoelectric element structure;

bonding the at least one piezoelectric element structure to a second substrate, the second substrate being conductive or having a conductive layer;

removing the at least one first substrate from the at least one piezoelectric element structure;

depositing a second side electrode on the first surface of the at least one piezoelectric element structure;

poling, by applying a DC voltage to the at least one piezoelectric element structure, to provide the at least one piezoelectric element structure with piezoelectric characteristics; and

performing a property test following the poling step to determine operational characteristics of the poled, at least one piezoelectric element structure on the second substrate, prior to bonding the at least one piezoelectric element structure to a final target substrate.