Abstract: A method is provided for reducing contact resistances in semiconductors. In the use of fluorocarbon plasmas during high selectively sub-quarter-micron contact hole etching, with the silicon dioxide(SiO2)/silicon nitride(Si3N4)/silicide(TiSix) layers, polymerization effects have been discovered to be crucial. The process includes using a high etch selective chemistry, to remove SiO2 first, then switching to another chemistry with high selectivity of Si3N4-to-TiSix. To obtain good etch selectivity of SiO2-to-Si3Nx, fluorocarbon plasmas containing high C/F ratio are employed. This results in the information of reactive unsaturated polymers which stick easily to contact sidewalls and bottoms. Fluorine from the polymer was discovered to severely degrade the etch selectivity of Si3N4-to-TiSix. Different polymer removing methods to restore etch selectivity of Si3N4-to-TiSix, are provided which can be applied to any highly selective etching of oxide versus nitride.

Abstract: A method for cleaning bonding pads on a semiconductor device, as disclosed herein, includes treating the bonding pads with a CF4 and water vapor combination. In the process, the water vapor breaks up and the hydrogen from the water vapor couples to fluorine residue on the bonding pad surface creating a volatile HF vapor. In addition, fluorine from the CF4 exchanges with the titanium in the metallic polymer residue making the polymer more soluble for the organic strip operation which follows. Next, the resist is ashed and then an organic resist stripper is applied to the bonding pad area, thereby creating a clean bonding pad surface. Thereafter, a reliable bond wire connection can be made to the bonding pad.

Abstract: A method for cleaning bonding pads on a semiconductor device, as disclosed herein, includes treating the bonding pads with a CF4 and water vapor combination. In the process, the water vapor breaks up and the hydrogen from the water vapor couples to fluorine residue on the bonding pad surface creating a volatile HF vapor. In addition, fluorine from the CF4 exchanges with the titanium in the metallic polymer residue making the polymer more soluble for the organic strip operation which follows. Next, the resist is ashed and then an organic resist stripper is applied to the bonding pad area, thereby creating a clean bonding pad surface. Thereafter, a reliable bond wire connection can be made to the bonding pad.

Abstract: A method is provided for reducing contact resistances in semiconductors. In the use of fluorocarbon plasmas during high selectively sub-quarter-micron contact hole etching, with the silicon dioxide(SiO2)/silicon nitride(Si3N4)/silicide(TiSix) layers, polymerization effects have been discovered to be crucial. The process includes using a high etch selective chemistry, to remove SiO2 first, then switching to another chemistry with high selectivity of Si3N4-to-TiSix. To obtain good etch selectivity of SiO2-to-Si3N4, fluorocarbon plasmas containing high C/F ratio are employed. This results in the formation of reactive unsaturated polymers which stick easily to contact hole sidewalls and bottoms. Fluorine from the polymer was discovered to severely degrade the etch selectivity of Si3N4-to-TiSix. Different polymer removing methods to restore etch selectivity of Si3N4-to-TiSix are provided which can be applied to any highly selective etching of oxide versus nitride.