Method of room temperature growth of SiOx on silicide as an etch stop layer for metal contact open of semiconductor devices

• US 7,538,029 B2
• Filed: 07/06/2005
• Issued: 05/26/2009
• Est. Priority Date: 07/06/2005
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Oonk, Matthew W., Lavoie, Christian, Murray, Conal E., Wang, Yun-Yu, Mello, Kevin E.
• Primary Examiner(s): Pizarro; Marcos D.
• Assistant Examiner(s): Anya; Igwe U.
• Application Number:
  US11/160,699
• Publication Number:
  US 20070010093A1
• Time in Patent Office: 1,420 Days
• Field of Search: 438/655
• US Class Current: 438/655
• CPC Class Codes: H01L 21/28518 the conductive layers comprising silicides H01L21/28537 takes precedence
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence
• CPC Class Codes: H01L 21/76897 Formation of self-aligned vias or contact plugs, i.e. involving a lithographically uncritical step self-aligned silicidation on field effect transistors H01L29/665

Abstract

Silicide is protected during MC RIE etch by first forming an oxide film over the silicide and, after performing MC RIE etch, etching the oxide film. The oxide film is formed from a film of alloyed metal-silicon (M-Si) on the layer of silicide, then wet etching the metal-silicon. An ozone plasma treatment process can be an option to densify the oxide film. The oxide film may be etched by oxide RIE or wet etch, using 500:1 DHF.

Claims

1. A method of forming a semiconductor device having a layer of silicide and a contact opening extending through an overlying dielectric layer to the layer of silicide, the method comprising the steps of:

before etching the contact opening, forming an oxide film over the layer of silicide; and

after etching the contact opening, etching the oxide film to expose the underlying layer of silicide; and

wherein the step of forming the oxide film comprises;

first forming a film of alloyed metal-silicon (M-Si) on top of the layer of silicide; and

then forming the oxide film by wet etching the metal-silicon to remove the metal and to oxidize the residual Si to form a layer of SiOx on top of the silicide.

2. The method of claim 1, wherein the step of etching the oxide film comprises:

performing oxide reactive ion etching (RIE).

3. The method of claim 1, wherein the step of etching the oxide film comprises:

using 500;

1 DHF.

4. The method of claim 1, further comprising the step of:

before applying the dielectric layer, depositing a nitride capping layer.

5. The method of claim 1, wherein:

the metal in the alloyed metal-silicon (M-Si) is selected from the group consisting of where M can be Ti, Ni, Co, or other transition metal.

6. The method of claim 1, wherein:

the wet etching comprises an etch solution of H₂SO₄ with H₂O₂.

7. The method of claim 1, further comprising the step of:

performing an ozone plasma treatment to densify the oxide.

8. The method of claim 1, wherein the device is a field effect transistor (FET), and the silicide comprises source and drain regions of the FET.

9. A method of protecting silicide during MC RIE etch comprising:

before performing MC RIE etch, forming an oxide film over the silicide; and

wherein the step of forming the oxide film comprises;

first forming a film of alloyed metal-silicon (M-Si) on the layer of silicide; and

then, forming the oxide film by wet etching the metal-silicon to remove the metal M and to oxidize the residual Si to form a layer of SiOx on top of the silicide; and

forming a nitride layer over the oxide film.

10. The method of claim 9, further comprising:

performing an ozone plasma treatment to densify the oxide.

11. The method of claim 9, further comprising:

after performing MC RIE etch, etching the oxide film.

12. The method of claim 11, wherein the step of etching the oxide film comprises:

performing oxide reactive ion etching (RIE).

13. The method of claim 11, wherein the step of etching the oxide film comprises:

a wet etch using 500;

1 DHF.