Method of making a CIG target by die casting

1. A method of making a sputtering target, comprising:

providing a backing structure, and

forming as cast die cast copper indium gallium sputtering target material on the backing structure.

2. A method as claimed in claim 1 , wherein the sputtering target material is formed by die casting the entire sputtering target material directly onto the backing structure comprising a cylindrical backing structure to form a cylindrical sputtering target.

3. A method as claimed in claim 2 , further comprising placing the cylindrical backing structure in a die cavity and injecting liquid copper indium gallium sputtering target material into the die cavity.

4. A method as claimed in claim 3 , wherein the step of placing the cylindrical backing structure in the die cavity comprises placing a positioning device inside a hollow space in the cylindrical backing structure and contacting an inner surface of the cylindrical backing structure while the backing structure is located in the die cavity.

5. A method as claimed in claim 4 , wherein the positioning device comprises at least two shells and a cam shaft located between the shells.

6. A method as claimed in claim 1 , wherein the sputtering target material is formed by die casting the sputtering target material in a liquid state into a die cavity to form at least one hollow disc segment followed by removing the at least one segment from the die cavity and bonding the at least one segment to a cylindrical backing structure.

7. A method as claimed in claim 6 , wherein the step of bonding the at least one segment to a cylindrical backing structure comprises bonding a plurality of segments to the backing structure using an indium or an indium-gallium allot bonding material.

8. A method as claimed in claim 7 , further comprising forming a barrier material on an inner surface of each segment.

9. A method as claimed in claim 1 , further comprising heating a die before or during the step of the casting followed by cooling the die after the step of die casting.

10. A method as claimed in claim 1 , wherein the backing structure has a planar shape.

11. A method as claimed in claim 1 , wherein;

from 0% to 10% of primary phase regions in the sputtering target material are of a size greater than 100 μm in any random 1 cm by 1 cm area of the sputtering target;

an average primary phase region in the sputtering target material is of a size not greater than 40 μm; and

the sputtering target material has an overall uniform composition.

12. A method as claimed in claim 1 , wherein:

from 0% to 10% of primary has regions in the sputtering target material are of a size greater than 50 μm in any random 1 cm by 1 cm area of the sputtering target;

an average primary phase region in the sputtering target material is of a size between 1 and 25 μm; and

the sputtering target material has an overall uniform composition.

13. A method as claimed in claim 1 , wherein:

from 1% to 5% of primary phase regions in the sputtering target material are of a size greater than 50 μm in any random 1 cm by 1 cm area of the sputtering target;

an average primary phase region in the sputtering target material is of size between 10 and 20 μm; and

the sputtering target material has an overall uniform composition.

14. A method as claimed in claim 1 , wherein the sputtering target material has an overall uniform composition of about 29-39 wt % copper, about 49-62 wt % indium, and about 8-16 wt % gallium.

15. A method as claimed in claim 1 , wherein:

the sputtering target material has a density of 100% to 107% as determined by a rule of mixtures;

the sputtering target material contains 0 to 7 vol % porosity;

the sputtering target material does not contain inclusions or pores greater than a 100 μm diameter sphere in size; and

the sputtering target material does not contain pores or cracks having a distance larger than 1000 μm.

16. A method as claimed in claim 1 , wherein:

the sputtering target material has a density of 100% to 107% as determined by a rule of mixtures;

the sputtering target material contains less than 0 to 3 vol % porosity;

the sputtering target material does not contain inclusions or pores greater than a 50 μm diameter sphere in size; and

the sputtering target material does not contain pores or cracks having a distance larger than 500 μm.

17. A method as claimed in claim 1 , wherein the sputtering target material is formed by rapid cooling of the liquid sputtering target material on the backing structure at a rate of 1-100° C./s.

18. A method as claimed in claim 1 , further comprising forming at least one bonding layer between the backing structure and the sputtering target material.

19. A method as claimed in claim 18 , wherein:

the step of forming the at least one bonding layer comprises forming a Cu or Cu alloy compatible layer over the backing structure and forming a protective liquid In, Ga or In—Ga alloy film over the compatible layer; and

the In, Ga or In—Ga alloy film forms a Cu—In—Ga diffusion bond layer between the copper indium gallium sputtering target material and the compatible layer.

20. A method as claimed in claim 19 , wherein:

the backing structure comprises a stainless steel backing structure.

21. A method as claimed in claim 20 , wherein:

the step of forming the at least one bonding layer further comprises forming a nickel or aluminum alloy bond coat layer between the compatible layer and the backing structure.

22. A method as claimed in claim 18 , wherein:

the step of forming the at least one bonding layer comprises forming a protective liquid In, Ga or In—Ga alloy film over a Cu or Cu alloy backing structure; and

a Cu—In—Ga diffusion bond layer is formed between the copper indium gallium sputtering target material and the backing structure.