Removal of Copper Etching Residue
Original Publication Date: 1988-Jul-01
Included in the Prior Art Database: 2005-Feb-15
Copper residue resulting from reactive ion etching (RIE) of a sputtered aluminum-copper film on tungsten can be removed by further etching in an argon plasma. When a bilayer film, such as aluminum-4% copper on tungsten, has been sputter-deposited at high substrate temperatures, the higher copper concentrations at the bottom of the film produce residues that cause corrosion and act as barriers to later etching of the underlayer. These residues are cleared by sputter etching, such as argon ions, prior to removal of the underlying tungsten layer. The copper residue removal can be carried out as an intermediate step between the aluminum-copper etching and tungsten etching during the same pumpdown of the process chamber by merely supplying an appropriate gas line.