Methods for etching a metal layer to form an interconnection structure for semiconductor applications

Patent metadata

Field	Value
Publication number	US-9960052-B2
Application number	US-201414243677-A
Country	US
Kind code	B2
Filing date	Apr 2, 2014
Priority date	Apr 2, 2014
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

Embodiments of the present invention provide methods for patterning a metal layer, such as a copper layer, to form an interconnection structure in semiconductor devices. In one embodiment, a method of patterning a metal layer on a substrate includes (a) supplying an etching gas mixture comprising a hydro-carbon gas into a processing chamber having a substrate disposed therein, the substrate having a metal layer disposed thereon, (b) exposing the metal layer to an ashing gas mixture comprising a hydrogen containing gas to the substrate, and (c) repeatedly performing steps (a) and (b) until desired features are formed in the metal layer. During the patterning process, the substrate temperature may be controlled at greater than 50 degrees Celsius.

First claim

The invention claimed is:

1. A method of patterning a metal layer on a substrate, comprising:
(a) supplying an etching gas mixture consisting essentially of a hydro-carbon gas into a processing chamber and removing between about 10 percent and about 30 percent of a thickness of a metal layer disposed on a substrate disposed in the processing chamber;
(b) subsequently switching the etching gas mixture to an ashing gas mixture consisting of a hydrogen gas and an inert gas, the ashing gas mixture exposed to the metal layer exposed on the substrate for etching byproduct removal; and
(c) repeatedly performing steps (a) and (b) until desired features are formed in the metal layer.

2. The method of claim 1 , the metal layer is a copper layer.

3. The method of claim 1 , wherein supplying the etching gas mixture further comprising:
etching the metal layer to a depth between about 30 Å and about 100 Å.

4. The method of claim 1 , wherein repeatedly performing steps (a) and (b) further comprises:
repeatedly performing the steps (a) and (b) for at least about 3 times.

5. The method of claim 1 , wherein the hydro-carbon gas is selected from a group consisting of methane (CH 4 ), ethane (C 2 H 6 ), propane (C 3 H 8 ), butane (C 4 H 10 ), pentane (C 5 H 12 ), hexane (C 6 H 14 ), propene, ethylene, propylene, butylene, pentene and combinations thereof.

6. The method of claim 1 , wherein the hydro-carbon gas is methane (CH 4 ).

7. The method of claim 1 , wherein the etching byproduct is generated from the etching the metal layer.

8. The method of claim 1 , wherein the etching byproduct includes hydro-carbon-copper complex compound.

9. The method of claim 1 , wherein the substrate temperature is controlled at greater than 50 degrees Celsius.

10. A method of patterning a metal layer on a substrate, comprising:
(a) performing an etching process comprising an etching gas mixture consisting essentially of a hydro-carbon gas on a metal layer disposed on a substrate in a processing chamber and removing between about 10 percent and about 30 percent of a thickness of the metal layer from the substrate;
(b) subsequently switching the etching process to perform an ashing process comprising an ashing gas mixture consisting essentially of a hydrogen gas and an inert gas on the metal layer for etching byproducts removal; and
(c) repeatedly performing steps (a) and (b) until desired features are formed in the metal layer.

11. The method of claim 10 , wherein the hydro-carbon plasma is formed from an etching gas mixture including methane (CH 4 ).

12. The method of claim 10 , wherein the hydrogen plasma is formed from an ashing gas mixture including H 2 gas.

13. The method of claim 10 , wherein the metal layer is copper layer.

14. The method of claim 13 , wherein the ashing process removes the etching byproducts including hydro-carbon-copper complex compound.

15. A method of patterning a metal layer on a substrate, comprising:
supplying an etching gas mixture consisting essentially of methane (CH 4 ) to a processing chamber having a substrate disposed therein, the substrate having a metal layer disposed thereon;
etching a portion of the metal layer from the substrate, wherein the portion of the metal layer is about 10 percent and about 30 percent of a thickness of the metal layer from the substrate;
subsequently switching the etching gas mixture to an ashing gas mixture consisting essentially of a hydrogen gas, the ashing gas mixture exposed to the metal layer exposed on the substrate for etching byproducts removal;
and
cyclically supplying the etching gas mixture and the ashing gas mixture to the processing chamber for at least three times until desired features are formed in the metal layer.

16. The method of claim 15 , wherein the metal layer is a copper layer.

Assignees

• Applied Materials Inc

Inventors

• Agarwal Sumit
• Chien Ann
• Kuo Chiu-Pien
• Hoinkis Mark
• Howard Bradley J

Classifications

• H10W20/0633

  using subtractive patterning of the conductive members · CPC title

• H10P50/71

  using masks for conductive or resistive materials · CPC title

• H10W20/072

  of dielectric parts comprising air gaps · CPC title

• H10W20/063

  by forming conductive members before forming protective insulating material · CPC title

• H10W20/46

  comprising air gaps · CPC title