Control of etch slope during etching of Pt in Ar/Cl-2/O-2 plasmas

Pt patterns of the 0.25 mu m design rule were etched at 20 degrees C using a magnetically enhanced reactive ion etcher. The main problem of this device integration process is the redeposition of the etch products onto the pattern sidewall, making it difficult to reduce the pattern size. In both cases using a photoresist mask and an oxide mask, the redeposits of the etch products onto the sidewall were reduced by the addition of Cl-2 to Ar, although the etch slope was lowered to 45 degrees. Using the oxide mask, by adding O-2 to the Cl-containing gas, the etch slope was increased up to 70 degrees, and the redeposits were removed by an HCl cleaning process.