Method of making sputtering target

• US 20050189401A1
• Filed: 02/22/2005
• Published: 09/01/2005
• Est. Priority Date: 02/27/2004
• Status: Active Grant

• Current Assignee: Howmet Aerospace, Inc.
• Original Assignee: Howmet Corporation (Howmet Aerospace, Inc.)
• Inventors: Huizenga, Robert H., Mussman, Steven D., Butzer, Greg A.
• Granted Patent: US 7,832,619 B2
• Time in Patent Office: Days
• US Class Current: 228/194
• CPC Class Codes: B23K 20/021 Isostatic pressure welding
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy

Abstract

A method of making a large Mo billet or bar for a sputtering target wherein two or more bodies comprising Mo are placed adjacent one another (e.g. stacked one on the other) with Mo powder metal present at gaps or joints between the adjacent bodies. The adjacent bodies are hot isostatically pressed to form a diffusion bond at each of the metal-to-Mo powder layer-to-metal joint between adjacent bodies to form a billet or bar that can be machined or otherwise formed to provide a large sputtering target. The number and dimensions of the Mo bodies placed adjacent one another are selected to yield a desired large size the billet or bar suitable for the sputtering target. The billet or bar for the sputtering target exhibits a microstructure comprising equiaxed grains of less than 30 microns grain size and exhibits a low oxygen content of less than about 100 ppm by weight.

Claims

1. Method of making a billet or bar comprising molybdenum, comprising diffusion bonding adjacent bodies comprising Mo together at a metal-to-powder metal layer-to-metal joint therebetween in a hot isostatic pressing operation wherein the powder metal layer comprises Mo.

2. The method of claim 1 wherein the powder metal layer has an oxygen content of less than about 1000 ppm by weight.

3. The method of claim 1 wherein the bodies have an oxygen content of less than about 100 ppm by weight.

4. The method of claim 1 including machining the billet or bar to form a sputtering target.

5. The method of claim 1 wherein the bodies each comprises a preform made by diffusion bonding adjacent sintered Mo powder metal bodies together at a metal-to-metal joint in a first hot isostatic pressing operation to form each preform.

6. The method of claim 5 wherein the sintered Mo powder metal bodies have an oxygen content of less than about 100 ppm by weight.

8. A billet or bar for a sputtering target made by the process of any one of claims 1-7.

9. A sputtering target made by the process of any one of claims 1-7.

7. Method of making an elongated billet or bar comprising molybdenum, comprising placing bodies comprising Mo adjacent one another, providing a metal powder comprising Mo between the adjacent bodies, and diffusion bonding the adjacent bodies with the metal powder therebetween in a hot isostatic pressing operation.

10. A billet or bar for a sputtering target having a HIP'"'"'ed microstructure comprising equiaxed grains of grain size of about 30 microns or less and an oxygen content of less than 100 ppm by weight.

11. The billet or bar of claim 10 having a diffusion bond joint where Mo powder metal formerly resided.