Method for etching a hardmask layer for an interconnection structure for semiconductor applications

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.

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.