METHOD FOR ETCHING A HARDMASK LAYER FOR AN INTERCONNECTION STRUCTURE FOR SEMICONDUCTOR APPLICATIONS
Embodiments of the present disclosure provide methods for patterning a hardmask layer disposed on a metal layer, such as a copper layer, to form an interconnection structure in semiconductor devices. In one embodiment, a method of patterning a hardmask layer on a metal layer disposed on a substrate includes supplying a first etching gas mixture comprising a carbon-fluorine containing gas and a chlorine containing gas into a processing chamber to etch a portion of a hardmask layer disposed on a metal layer formed on a substrate, supplying a second etching gas mixture comprising a hydrocarbon gas into the processing chamber to clean the substrate, and supplying a third etching gas mixture comprising a carbon-fluorine containing gas to remove a remaining portion of the hardmask layer until a surface of the metal layer is exposed.
1 . A method of patterning a hardmask layer disposed on a metal layer formed on a substrate, comprising:
supplying a first etching gas mixture comprising a carbon-fluorine containing gas and a chlorine containing gas into a processing chamber to etch a portion of a hardmask layer disposed on a metal layer formed on a substrate;
supplying a second etching gas mixture comprising a hydrocarbon gas into the processing chamber to clean the substrate and the hardmask layer; and
supplying a third etching gas mixture comprising a carbon-fluorine containing gas to remove a remaining portion of the hardmask layer until a surface of the metal layer is exposed.
2 . The method of claim 1 , the metal layer is a copper layer.
3 . The method of claim 1 , wherein the hardmask layer is a Ta containing material or a Ti containing material.
4 . The method of claim 1 , wherein supplying the first etching gas mixture further comprising:
etching the hardmask layer to a depth of between about 50 percent and about 90 percent of a total thickness of the hardmask layer.
5 . The method of claim 1 , wherein supplying the second etching gas mixture further comprising:
supplying the second gas mixture into the processing chamber for a first period of time without applying RF source power or RF bias power.
6 . The method of claim 5 , further comprising:
applying a RF source power or a RF bias power to the second gas mixture for a second period of time after the first period of time.
7 . The method of claim 1 , wherein the hydrocarbon gas supplied in the second gas mixture 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.
8 . The method of claim 1 , wherein the hydrocarbon gas supplied in the second gas mixture is methane (CH 4 ).
9 . The method of claim 1 , wherein the carbon-fluorine containing gas supplied in the first and the third gas mixture is selected from a group consisting of CFH 3 , CF 2 H 2 , CF 3 H, C 2 F 2 H 4 , C 2 F 2 H 6 , CF 4 and C 2 F 6 .
10 . The method of claim 9 , wherein the carbon-fluorine containing gas supplied in the first gas mixture is CF 3 H.
11 . The method of claim 9 , wherein the carbon-fluorine containing gas supplied in the third gas mixture is CF 4 .
12 . The method of claim 1 , wherein the chlorine containing gas supplied in the first gas mixture is Cl 2 gas.
13 . The method of claim 1 further comprising:
performing an ashing process to remove etching byproducts from the substrate surface.
14 . The method of claim 13 , wherein the ashing process comprises supplying a H 2 gas into the processing chamber.
15 . The method of claim 1 , wherein the second etching gas mixture further comprises an oxygen containing gas.
16 . The method of claim 15 , wherein the hydrocarbon gas and the oxygen containing gas is supplied at a ratio between about 10:1 and about 5:1.
17 . A method of patterning a hardmask layer disposed on a metal layer formed on a substrate, comprising:
performing an etching break-through process to etch a depth of a hardmask layer disposed on a metal layer formed on the substrate, wherein the depth of the hardmask layer is between about 50 percent and about 90 percent of a total thickness of the hardmask layer, wherein the hardmask layer is a Ta containing material or a Ti containing material;
performing a flash cleaning process to remove etching residuals from the substrate; and
performing an interface cleaning process to etch a remaining portion of the hardmask layer from the substrate, wherein the interface cleaning process is performed by supplying an etching gas mixture including a hydrogen free carbon-fluorine containing gas.
18 . The method of claim 17 , wherein the hydrogen free carbon-fluorine containing gas is CF 4 .
19 . The method of claim 17 , wherein the flash cleaning process comprises supplying a gas mixture including a hydrocarbon gas and an oxygen containing gas supplied at a ratio between about 10:1 and about 5:1.
20 . A method of patterning a hardmask layer disposed on a metal layer formed on a substrate, comprising:
performing an etching break-through process by supplying a first gas mixture to etch a depth of a hardmask layer disposed on a metal layer formed on the substrate, wherein the depth of the hardmask layer is between about 50 percent and about 90 percent of a total thickness of the hardmask layer, the first gas mixture including a carbon-fluorine containing gas and a chlorine containing gas;
performing a flash cleaning process to remove etching residuals from the substrate by supplying a second gas mixture including a hydrocarbon gas; and
performing an interface cleaning process to etch a remaining portion of the hardmask layer from the substrate by supplying a third etching gas mixture including a hydrogen free carbon-fluorine containing gas.