ETCHING PIEZOELECTRIC MATERIAL

• US 20110117311A1
• Filed: 05/12/2009
• Published: 05/19/2011
• Est. Priority Date: 05/22/2008
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Birkmeyer, Jeffrey, Li, Youming
• Granted Patent: US 9,085,152 B2
• Time in Patent Office: Days
• US Class Current: 428/80
• 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 2/1628 dry etching
• CPC Class Codes: B41J 2/1629 wet etching
• CPC Class Codes: B41J 2/1632 machining
• CPC Class Codes: B41J 2/1646 thin film formation by sputtering
• CPC Class Codes: H01L 21/31138 by dry-etching
• CPC Class Codes: H10N 30/082 by etching, e.g. lithography
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
• CPC Class Codes: Y10T 428/24917 including metal layer

Abstract

Piezoelectric material is shaped by plasma etching to form deep features with high aspect ratios, and desired geometries.

Claims

1. A method comprising:

shaping a piezoelectric material by exposing the material to plasma etching conditions and

etching a feature having a depth of about 1 micron or more.

2. The method of claim 1 comprising forming a feature having a depth of about 5 microns or more.

3. The method of claim 1 comprising forming a feature having an aspect ratio of about 2 to 1 or greater.

4. The method of claim 1 comprising forming an island having an edge shape other than a square or a rectangle.

5. The method of claim 1 comprising etching at a rate of about 50 nm/min or more.

6. The method of claim 5 comprising etching at a rate of about 100 nm/min or more.

7. The method of claim 1 wherein the piezoelectric material is poled prior to etching and etching said feature without depoling the material.

8. The method of claim 1 comprising etching while maintaining the piezoelectric material below the Curie temperature.

9. The method of claim 1 comprising providing a mask to define the feature, wherein the mask etches at a rate about four or more times less than the rate of etching the piezoelectric material.

10. The method of claim 1 comprising providing a mask material and patterning the mask material by wet etching to define a location of a feature.

11. The method of claim 1 comprising providing a mask to define the feature, wherein the mask is removed by wet etching after etching said feature.

12. The method of claim 1 wherein the masking material is a metal including NiCr or a combination thereof.

13. The method of claim 1 wherein the piezoelectric material being supported on a platen during etching and the platen temperature is about 100°

C. or less.

14. The method of claim 13 wherein the platen temperature is about 30°

C. or less.

15. The method of claim 1 comprising reducing the thickness of the piezoelectric material after etching.

16. The method of claim 1 comprising utilizing the etched piezoelectric material in an actuator.

17. The method of claim 1 comprising utilizing the actuator in an ink jet printhead.

18. A method comprising:

shaping a piezoelectric material by exposing the material to plasma etching conditions,

etching a feature having an aspect ratio of about 2 to 1 or more, and

forming an island having an edge shape other than a square or a rectangle.

20. The assembly of claim 18 wherein the piezoelectric material is a wafer of uniform thickness.

21. The assembly of claim 18 wherein the piezoelectric material is a wafer having a feature corresponding to the mask pattern feature, wherein the wafer feature has a depth of about 5 micron or more.

22. The assembly of claim 21 wherein the feature has an aspect ratio of about 2 to 1 or greater.

23. The assembly of claim 21 wherein the feature has an edge shape other than a square or a rectangle.

24. The assembly of claim 18 wherein the masking material is a metal.

25. The method of claim 18 wherein the thickness of the masking material is about 3 micron or more.

26. The assembly of claim 24 wherein the metal is etchable by ceric ammonium nitrate wet etch.

19. An assembly, comprising:

a piezoelectric material with a thickness of about 5 to 25 microns, and

a masking material having a pattern feature defining the location of said piezoelectric feature, the masking material having a thickness of about 20 micron or less and the mask pattern feature having an aspect ratio of about 10 to 1 or less.

27. A method of processing piezoelectric material, comprising:

providing a piezoelectric substrate,

depositing a masking material on a surface of the substrate,

patterning the masking material to form a mask pattern using a wet etch,

transferring the patterning of the mask to the piezoelectric substrate to form piezoelectric features using a plasma etch, and

stripping the mask material using a wet etch.

28. The method of claim 27 wherein the masking material is a metal.

29. The method of claim 28 wherein the masking material has a thickness of about 10 micron or less.

30. The method of claim 29 wherein the mask pattern has features with an aspect ratio of about 10 to 1 or less.

31. The method of claim 27 wherein at least one of the piezoelectric features has a depth of about 5 microns or more.