Process for the removal of contaminants from sputtering target substrates

• US 10,138,545 B2
• Filed: 02/02/2017
• Issued: 11/27/2018
• Est. Priority Date: 02/05/2016
• Status: Active Grant

• Current Assignee: SCI Engineered Materials, Inc.
• Original Assignee: SCI Engineered Materials, Inc.
• Inventors: Young, Jeremy R.
• Primary Examiner(s): Carlson, Marc
• Application Number:
  US15/422,666
• Publication Number:
  US 20170226628A1
• Time in Patent Office: 663 Days
• CPC Class Codes: B08B 3/10 with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
• CPC Class Codes: B24B 7/22 for grinding inorganic material, e.g. stone, ceramics, porcelain
• CPC Class Codes: C11D 2111/16 Metals
• CPC Class Codes: C11D 2111/20 Industrial or commercial equipment, e.g. reactors, tubes or engines
• CPC Class Codes: C11D 2111/44 Multi-step processes
• CPC Class Codes: C11D 2111/46 applying energy, e.g. irradiation
• CPC Class Codes: C11D 3/042 Acids
• CPC Class Codes: C11D 3/2003 Alcohols; Phenols
• CPC Class Codes: C11D 3/2072 Aldehydes-ketones
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: C23C 22/00 Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
• CPC Class Codes: G01N 23/223 by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence

Abstract

The present invention provides a process for the removal of contaminants on a spent sputtering target used in Plasma Vapor Deposition by the steps of grit abrasion, organic solvent cleaning, and being subjected to an electric field in an acidic bath including a surfactant, and followed by subsequent water and air rinse and further grit abrasion. Removal of the contaminants is verified by spectroscopy.

Claims

1. A method for the removal of chromium contaminants on a ruthenium sputtering target used in plasma vapor deposition including the steps of

subjecting the ruthenium sputtering target to grit abrasion followed by an organic solvent cleaning to result in a pre-cleaned target,

subjecting the pre-cleaned target to an electric field in an acidic bath including a surfactant, followed by subsequent water and air rinse.

2. A method as set forth in claim 1 wherein the target is subjected to a second grit abrasion following the water and air rinse.

3. A method as set forth in claim 1 wherein the removal of the chromium contaminants is verified by spectroscopy.

4. A method as set forth in claim 3 wherein the spectroscopy is XRF.

5. A method as set forth in claim 1 wherein one of 120 or 180 grit aluminum oxide is used.

6. A method as set forth in claim 2 wherein 120 grit aluminum oxide is used in the grit abrasion and 180 grit aluminum oxide is used in the second grit abrasion.

7. A method as set forth in claim 1 wherein the electric field is 120 volts which is applied to the ruthenium sputtering target wherein the ruthenium sputtering target is held in a container in the acidic bath and the electric field is applied to the bath.

8. A method as set forth in claim 1 wherein the electric field is 120 volts which is applied to the ruthenium sputtering target wherein the ruthenium sputtering target is held in a container in the acidic bath and the electric field is applied to the container which holds the sputtering target.

9. A method as set forth in claim 1 wherein the organic solvent is a C1-6 alcohol or ketone.

10. A method as set forth in claim 9 wherein the organic solvent is a C1-3 alcohol or ketone.

11. A method as set forth in claim 10 wherein the caustic bath is an acidic bath having a pH of from 1 to 4.

12. A method as set forth in claim 11 wherein the acidic bath has a pH of from 2.5 to 3.5.

13. A method as set forth in claim 11 wherein the caustic bath further includes a surfactant.

14. A method as set forth in claim 13 wherein the surfactant is dish soap.

15. A method as set forth in claim 1 wherein the caustic bath is at a temperature of from 22°

to 100°

C.

16. A method for the removal of chromium contaminants on a ruthenium substrate including the steps of

subjecting the ruthenium substrate to grit abrasion using 120 to 180 grit aluminum oxide followed by an organic solvent cleaning to result in a pre-cleaned substrate having a matte finish, and the organic solvent comprising C_1-6 alcohol or ketone,

subjecting the pre-cleaned substrate to an electric field at 50-150 volts in an acidic bath at a pH of 1-4 and including a surfactant, followed by subsequent water and air rinse;

and subjecting the substrate to second grit abrasion using 120 to 180 grit aluminum oxide, following the water and air rinse.

17. A method as set forth in claim 16 wherein the removal of the chromium contaminants is verified by spectroscopy.

18. A method as set forth in claim 17 wherein the acidic bath is sulfuric or hydrochloric acid and the organic solvent is isopropyl alcohol.