Methods for etching an etching stop layer utilizing a cyclical etching process

• US 8,980,758 B1
• Filed: 09/17/2013
• Issued: 03/17/2015
• Est. Priority Date: 09/17/2013
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Kang, Sean S., Pender, Jeremiah T. P., Nemani, Srinivas D., Howard, Bradley, Ling, Mang-Mang
• Primary Examiner(s): Deo, Duy
• Application Number:
  US14/029,769
• Publication Number:
  US 20150079798A1
• Time in Patent Office: 546 Days
• US Class Current: 438/706
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/76802 by forming openings in dielectrics
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76829 characterised by the formation of thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers

Abstract

Methods for etching an etching stop layer disposed on the substrate using a cyclical etching process are provided. In one embodiment, a method for etching an etching stop layer includes performing a treatment process on the substrate having a silicon nitride layer disposed thereon by supplying a treatment gas mixture into the processing chamber to treat the silicon nitride layer, and performing a chemical etching process on the substrate by supplying a chemical etching gas mixture into the processing chamber, wherein the chemical etching gas mixture includes at least an ammonium gas and a nitrogen trifluoride, wherein the chemical etching process etches the treated silicon nitride layer.

Claims

1. A method for etching an etching stop layer comprising:

(a) performing a treatment process on the substrate having a silicon nitride layer disposed thereon by supplying a treatment gas mixture into the processing chamber to treat the silicon nitride layer;

(b) performing a chemical etching process on the substrate by supplying a chemical etching gas mixture into the processing chamber, wherein the chemical etching gas mixture includes at least an ammonium gas and a nitrogen trifluoride, wherein the chemical etching process etches the treated silicon nitride layer; and

repeatingly performing step (a)-step (b) to etch the silicon nitride layer until an underlying substrate is exposed.

2. The method of claim 1, further comprising:

(c) performing a transition process on the etched substrate by supplying a transition gas mixture into the processing chamber after performing step (b).

3. The method of claim 2, wherein the transition gas mixture includes at least a hydrogen containing gas, a nitrogen containing gas or an inert gas.

4. The method of claim 2, further comprising:

repeatingly performing step (a)-step (c) to etch the silicon nitride layer until an underlying substrate is exposed.

5. The method of claim 2, wherein performing the transition process further comprises:

supplying the transition gas mixture to remove etching residual without applying a RF power.

6. The method of claim 1, wherein the treatment gas mixture includes at least a hydrogen containing gas, a nitrogen containing gas or an inert gas.

7. The method of claim 1, wherein performing the treatment process on the substrate further comprises:

applying a RF bias power to the treatment gas mixture.

8. The method of claim 1, wherein performing the chemical etching process on the substrate further comprises:

applying a RF source power to the chemical etching gas mixture remotely from the processing chamber.

9. The method of claim 1, wherein performing the chemical etching process on the substrate further comprises:

supplying the ammonium gas and the nitrogen trifluoride in the chemical etching gas mixture a molar ratio of from about 5;

1.

10. The method of claim 1, further comprising:

maintaining a substrate temperature between about 50 degrees and about 150 degrees Celsius.

11. The method of claim 1, wherein the silicon nitride layer is an etching stop layer utilized in a contact structure in a semiconductor device.

12. A method for etching an etching stop layer comprising:

(a) transferring a substrate having a silicon nitride layer disposed thereon in a processing chamber, wherein a patterned silicon oxide layer along with a pattered mask layer disposed on the silicon nitride layer exposing a portion of the silicon nitride layer;

(b) supplying a treatment gas mixture to treat the exposed portion of the silicon nitride layer, wherein the treatment gas mixture includes an inert gas; and

(c) supplying a chemical etching gas mixture into the processing chamber, wherein the chemical etching gas mixture includes at least an ammonium gas and a nitrogen trifluoride to etch the treated silicon nitride layer; and

repeatingly performing steps (b) and (c) until the exposed portion of the silicon nitride layer is removed from the substrate.

13. The method of claim 12, further comprising:

(d) supplying a transition gas mixture to the processing chamber, wherein the transition gas mixture includes an inert gas after performing step (c).

14. The method of claim 12, wherein the ammonium gas and the nitrogen trifluoride in the chemical etching gas mixture a molar ratio of from about 3:

1 to about 30;

1.

15. The method of claim 12, further comprises:

applying a RF bias power to the treatment gas mixture;

applying a RF source power remotely from the processing chamber to the chemical etching gas mixture.

16. The method of claim 13, wherein supplying the transition gas mixture further comprises:

supplying the transition gas mixture to remove etching residual without applying a RF power.

17. A method for etching a silicon nitride layer comprising:

(a) transferring a substrate having a silicon nitride layer disposed on a metal silicide structure into a processing chamber, wherein the silicon nitride layer has a patterned silicon oxide layer along with a pattered mask layer disposed thereon exposing a portion of the silicon nitride layer;

(b) supplying a Ar or He gas while applying a RF bias power to treat the exposed silicon nitride layer;

(c) supplying a chemical etching gas mixture including at least an ammonium gas and a nitrogen trifluoride while applying a RF source power remotely from the processing chamber to etch the treated silicon nitride layer; and

(d) supplying a Ar or He gas to the processing chamber without applying a RF power.

18. The method of claim 17, further comprising:

repeatedly performing steps (b) to (d) until the exposed portion of the silicon nitride layer is removed exposing the underlying metal silicide structure.