Method for forming metal silicide layer of semiconductor device combining just dry etching and chemical dry etching

摘要

through the just dry etching to expose the polysilicon, a metal recess the oxide film through a chemical dry etching It relates to a method of forming the silicide film. In order to reduce the contact resistance, increasing the moving velocity of the electron, in the salicide process for capping the metal on the gate, prior to depositing the metal on the polysilicon of the gate, it is necessary to expose the polysilicon. As the line width of the polysilicon is narrow, the loss becomes large when the opening of the polysilicon, the silicon substrate tends to be touch dry etching can. Therefore, in order to prevent over-etching, a dry etching is performed so that the exposed polysilicon drive. 2 is subjected to chemical dry etching to expose the polysilicon completely away. Chemical dry etching, NF ₃ and NH _3, , HF and NH _3, or N ₂ and H ₂ and NF ₃ , select the etchant source on from a combination of the dissociation of the etchant source plasma, remote plasma hokneun column by and through the dissociation NH ₄ F and NH ₄ F form an etchant of HF, oxide etchant in low temperatures (SiO ₂ ) and reacted in the solid state ( NH ₄ ) ₂ SiF ₆ creates a by-product and, SiF gas phase by annealing the by-products at high temperatures ₄ / NH ₃ / HF sublimate into. ; silicide, polysilicon, dry etching, etchant, sublimation