Carbon-doped hard mask and method of passivating structures during semiconductor device fabrication

• US 20020074313A1
• Filed: 12/19/2000
• Published: 06/20/2002
• Est. Priority Date: 12/19/2000
• Status: Active Grant

• Current Assignee: Bell Semiconductor, LLC (Hilco Inc. (d/b/a Hilco Global))
• Original Assignee: LSI Logic Corporation (Broadcom, Inc.)
• Inventors: Hu, John, Schoenborn, Philippe, Ley, Ana
• Granted Patent: US 6,576,404 B2
• Time in Patent Office: Days
• US Class Current: 216/41
• CPC Class Codes: C23F 4/00 Processes for removing metallic material from surfaces, not provided for in group C23F1/00 or C23F3/00
• CPC Class Codes: H01L 21/32139 using masks
• CPC Class Codes: Y10T 428/24322 Composite web or sheet

Abstract

A carbon-doped hard mask includes a dielectric material containing carbon which is released from the hard mask during a metal etching process. The released carbon is deposited on and bonds to sidewalls of the metal structure during the metal etching process to passivate the sidewalls of the metal structure and prevent lateral etching of the sidewalls during the metal etching process. The released carbon also prevents became relation to metal residue in open fields.

Claims

1. A carbon-doped hard mask for use in etching a substance to form a structure with an etching process during a semiconductor fabrication process, the structure having sidewalls formed during the etching process, the hard mask including:

a dielectric material layer containing carbon which is released in sufficient quantities from the dielectric material layer during the etching process to passivate the sidewalls of the structure against lateral etching.

2. A carbon-doped hard mask as defined in claim 1 wherein the the carbon is further released in sufficient quantities from the dielectric material layer during the etching process to prevent residue in an open field of the structure.

3. A carbon-doped hard mask as defined in claim 1 wherein the substance is a conductive metal.

4. A carbon-doped hard mask as defined in claim 1 wherein the dielectric material is carbon doped silicon oxide.

5. A carbon-doped hard mask as defined in claim 1 wherein the dielectric material is carbon silicon oxide.

6. A carbon-doped hard mask as defined in claim 1 wherein the dielectric material includes a silicon material containing carbon.

7. A carbon-doped hard mask as defined in claim 1 wherein the carbon released from the hard mask combines with a chemical plasma in an atmosphere surrounding the substance before passivating the sidewalls of the structure.

8. A method of passivating sidewalls of a structure formed under a hard mask from a substance during an etching process in a semiconductor fabrication process, the method including the steps of:

forming the hard mask on the substance from dielectric material containing carbon;

releasing carbon from the dielectric material during the etching process; and

etching the substance in a vertically downward direction to form the structure while the released carbon protects sidewalls of the structure from lateral etching.

9. A method as defined in claim 8 further comprising the step of:

preventing residue accumulation in an open field of the structure from the released carbon.

10. A method as defined in claim 8 further including the step of:

forming the hard mask using a photoresist mask in a photolithography process.

11. A method as defined in claim 10 further including the step of:

removing the photoresist mask from the hard mask before etching the substance.

12. A method as defined in claim 10 further including the step of:

simultaneously removing the photoresist mask and the hard mask after etching the substance.

13. A method as defined in claim 10 further including the step of:

removing the photoresist mask from the hard mask after etching the substance.

14. A method as defined in claim 13 further including the step of:

selectively removing portions of the hard mask from the substance leaving remaining portions of the hard mask on the substance and after etching the metal layer; and

using remaining portions of the hard mask in the semiconductor fabrication process to form part of a semiconductor device.

15. A method as defined in claim 8 further including the step of:

forming the hard mask from carbon silicon oxide.

17. A method as defined in claim 16 further comprising the step of:

forming the mask from a dielectric material which contains the passivating agent in sufficient quantities which when released passivate the sidewalls.

18. A method as defined in claim 17 wherein the passivating agent is carbon and the substance is a metal layer.

16. A method of inhibiting lateral etching of a structure formed in a semiconductor fabrication process by vertically etching a substance to form the structure, comprising the steps of:

forming a mask on the substance containing a passivating agent which is released from the mask during etching;

etching the substance into the structure using the mask while the passivating agent is released from the mask to passivate sidewalls of the structure from lateral etching as the structure is etched from the substance.