Method for processing a lithium tantalate crystal substrate

1. A method for processing a lithium tantalate crystal substrate, comprising:

providing a lithium tantalate crystal substrate and a metallic sheet;

roughening at least one of the lithium tantalate crystal substrate and the metallic sheet;

bringing the lithium tantalate crystal substrate and the metallic sheet into contact with each other after the at least one thereof is roughened; and

subjecting the lithium tantalate crystal substrate to a reduction treatment,

wherein the reduction treatment is conducted at a temperature not higher than a Curie temperature of the lithium tantalate crystal substrate, and

wherein the at least one of the lithium tantalate crystal substrate and the metallic sheet is roughened via a chemical etching treatment.

2. The method as claimed in claim 1 , wherein the metallic sheet has a thickness ranging from 0.05 mm to 20 mm.

3. The method as claimed in claim 1 , wherein the metallic sheet comprises a metal component selected from the group consisting of aluminum, titanium, zinc, iron, and combinations thereof.

4. The method as claimed in claim 1 , wherein the chemical etching treatment is a wet etching treatment.

5. The method as claimed in claim 1 , wherein the at least one of the lithium tantalate crystal substrate and the metallic sheet is roughened to have a surface roughness that is larger than 3 μm and not greater than 10 μm.

6. The method as claimed in claim 1 , wherein the reduction treatment is conducted in the presence of a gas selected from the group consisting of a hydrogen gas, a carbon monoxide gas, a nitrous oxide gas, a nitrogen gas, an argon gas, and combinations thereof.

7. The method as claimed in claim 6 , wherein the gas has a flow rate ranging from 0.3 to 5.0 liters per minute.

8. The method as claimed in claim 1 , wherein the temperature for conducting the reduction treatment ranges from 350° C. to 610° C.

9. The method as claimed in claim 8 , wherein the reduction treatment is conducted for 3 to 12 hours.

10. The method as claimed in claim 1 , wherein the reduction treatment is conducted at a pressure ranging from 3.0 kPa to 20 kPa.

11. The method as claimed in claim 1 , wherein the lithium tantalate crystal substrate is roughened.

12. The method as claimed in claim 1 , wherein the metallic sheet is roughened.

13. The method as claimed in claim 1 , wherein the lithium tantalate crystal substrate and the metallic sheet are roughened.

14. A method for processing a lithium tantalate crystal substrate, comprising:

providing a lithium tantalate crystal substrate and a metallic sheet;

roughening at least one of the lithium tantalate crystal substrate and the metallic sheet;

bringing the lithium tantalate crystal substrate and the metallic sheet into contact with each other after the at least one thereof is roughened; and

subjecting the lithium tantalate crystal substrate to a reduction treatment,

wherein the reduction treatment is conducted at a temperature not higher than a Curie temperature of the lithium tantalate crystal substrate, and

wherein the at least one of the lithium tantalate crystal substrate and the metallic sheet is roughened to have a surface roughness that is larger than 3 μm and not greater than 10 μm.

15. The method as claimed in claim 14 , wherein the reduction treatment is conducted at a pressure ranging from 3.0 kPa to 20 kPa.

16. A method for processing a lithium tantalate crystal substrate, comprising:

providing a lithium tantalate crystal substrate and a metallic sheet;

roughening at least one of the lithium tantalate crystal substrate and the metallic sheet;

bringing the lithium tantalate crystal substrate and the metallic sheet into contact with each other after the at least one thereof is roughened; and

subjecting the lithium tantalate crystal substrate to a reduction treatment,

wherein the reduction treatment is conducted at a temperature not higher than a Curie temperature of the lithium tantalate crystal substrate, and

wherein the reduction treatment is conducted at a pressure ranging from 3.0 kPa to 20 kPa.