METHOD FOR REMOVING TUNGSTEN RESIDUES OF SEMICONDUCTOR DEVICE WITH TUNGSTEN/POLYSILICON GATE BY BLOCKING OUTGASSING OF TUNGSTEN

摘要

PURPOSE: A method for removing tungsten residues of a semiconductor device with a tungsten/polysilicon gate is provided to prevent degradation and junction leakage of a gate oxide layer by blocking the outgassing of tungsten before depositing a gate sealing nitride layer and to compensate the thickness of a lost hard mask by depositing additionally a PE(Plasma Enhanced) silicon nitride layer. CONSTITUTION: A gate pattern including a polysilicon layer(2) and a tungsten film(3) is formed on a substrate, and a hard mask(4) is formed on the gate pattern. To compensate the damage of gate edges, a gate bird's beak(6) is formed at the lower edges of the polysilicon layer by selective oxidation. Tungsten residues generated in the selective oxidation are removed by wet etching solutions. A gate sealing nitride layer(7) is then formed on the resultant structure in order to prevent abnormal oxidation of W. A PE-SiN layer(5) is covered on the gate pattern.