Non-planar sputter targets having crystlallographic orientations promoting uniform deposition

• US 20090235709A1
• Filed: 05/29/2009
• Published: 09/24/2009
• Est. Priority Date: 09/13/2002
• Status: Active Grant

• Current Assignee: Tosoh SMD, Inc. (Tosoh Corporation)
• Original Assignee: Tosoh SMD, Inc. (Tosoh Corporation)
• Inventors: Smathers, David B., Bailey, Robert S., Wiemels, Timothy, Holcomb, Melvin K.
• Granted Patent: US 8,037,727 B2
• Time in Patent Office: Days
• US Class Current: 72/63
• CPC Class Codes: C23C 14/3407 Cathode assembly for sputtering apparatus, e.g. Target
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: H01J 37/34 operating with cathodic sputtering H01J37/36 takes precedence ; methods of cathodic sputtering C23C14/34
• CPC Class Codes: H01J 37/3426 Material
• CPC Class Codes: Y10T 29/49805 Shaping by direct application of fluent pressure

Abstract

A non-planar sputter target having differing crystallographic orientations in portions of the sputter target surface that promote more desirable deposition and density patterns of material sputtered from the target surface onto a substrate. A closed dome end of the sputter target is comprised of a first crystallographic orientation and sidewalls of the sputter target are comprised of a crystallographic orientation different from that of the dome. The sputter target is formed, preferably by hydroforming or other metal working techniques, in the absence of annealing. The hydroforming manipulations result in the different crystallographic orientations while minimizing, or ideally omitting, the application of heat. Quick and cost effective non-planar sputter targets that are easily repeatably producable are achievable as a result.

Claims

1. In a method of making a generally pot shaped sputter target having a first sputtering region defining a planar end wall or dome and a second sputtering region defining a sidewall connected to and extending from said first sputtering region to form an open end of said sputter target, the method of forming different crystallographic orientations in said first and second sputtering regions, the method comprising:

a. providing a hydroforming press having a platen, a housing holding a fluid filled bladder, and a mandrel;

b. providing a metallic blank having a given crystallographic orientation, said blank having a first area that, as a result of said forming, will define said first sputtering region of said target, said blank further having a second area that, as a result of said forming, will define said second sputtering region of said target;

c. placing said metallic blank between said mandrel and said bladder;

d. providing relative movement between said mandrel and said bladder to press said blank therebetween;

e. continuing to press said blank and cold working said blank in said second area of said blank thereby deforming said second area of said blank to about 35% or greater; and

f. releasing said blank from between said mandrel and said bladder thereby yielding a sputter target wherein said second sputtering region of said target has a crystallographic orientation that is different from said given crystallographic orientation and from the crystallographic orientation of said first sputtering region.

2. Method as recited in claim 1 wherein said bladder attains a pressure of up to about 15,000 psi during the pressing.

3. Method as recited in claim 1 wherein said pressing is conducted at room temperature.

4. Method as recited in claim 1 wherein the crystallographic orientation of said first sputtering region of said target is substantially the same as said given crystallographic orientation of said blank.

5. Method as recited in claim 4 wherein said blank is a high purity metal selected from the group consisting of titanium, copper, tantalum, and alloys thereof.

6. Method as recited in claim 5 wherein said metal is tantalum and said given crystallographic orientation of said blank is a mixed {111}/{100}.

7. Method as recited in claim 6 wherein said second sputtering region of said target has a mixed crystallographic orientation of {112}/{110}.

8. A method of forming a sputter target assembly having first and second sputtering surfaces with said first sputtering surface having a first crystallographic orientation and said second sputtering surface having a second crystallographic orientation that is different than said first crystallographic orientation, said method comprising:

a. providing a metallic blank having said first crystallographic orientation throughout, said blank having a first area thereof that, after said forming, will define said first sputtering surface of said target, said metallic blank also having a second area that, after said forming, will define said second sputtering surface of said target;

b. cold working said second area of said blank while pressing said blank into a desired shape, said cold working deforming said second area to about 35% or greater, to thereby form a sputter target wherein said first sputtering surface has said first crystallographic orientation and said second sputtering surface has said second crystallographic orientation.

9. Method as recited in claim 8 wherein said method is devoid of any heat treatment annealing so that said second region of said blank will not recrystallize.

10. Method as recited in claim 8 wherein said deforming is about 50% or greater.

11. Method as recited in claim 8 wherein said step of cold working said second region of said blank while pressing said blank is performed in a hydroforming apparatus operated at about room temperature.

12. Method as recited in claim 8 wherein said metallic blank is a high purity metal selected from the group consisting of titanium, copper, tantalum, and alloys thereof.

13. Method as recited in claim 12 wherein said metal is tantalum and said first crystallographic orientation of said blank is mixed {111}/{100}.

14. Method as recited in claim 13 wherein said cold working and pressing of said second area of said blank imparts a mixed crystallographic orientation of {112}/{110} to said second sputtering surface.

15. Method as recited in claim 14 wherein said sputter target has a generally pot shape and wherein said first sputtering surface of said target defines a dome and said second sputtering surface of said target defines sidewalls connected to and extending away from said dome.