Abstract: The method for avoiding polysilicon film over etch abnormal includes cleaning a semiconductor substrate. A dielectric layer is formed on the substrate. Subsequently, a first silicon source gas at a first flow rate is next performed injecting into a reaction chamber to form a first polysilicon film over the dielectric layer. Successively, a second silicon source gas at a second flow rate is performed injecting into the reaction chamber to form a second polysilicon film over the first polysilicon film, wherein the second silicon source gas having a different growth rate than the first silicon source gas. A patterned photoresist layer is then formed on the second polysilicon film. After the patterned photoresist layer is formed, a dry etching process by way of using the patterned photoresist layer as a etching mask is performed to etch through in turn the second polysilicon film and the first polysilicon film till exposing to the dielectric layer. Finally, the photoresist layer is removed.

Abstract: The method for avoiding polysilicon film over etch abnormal includes cleaning a semiconductor substrate. A dielectric layer is formed on the substrate. Subsequently, a first silicon source gas at a first flow rate is next performed injecting into a reaction chamber to form a first polysilicon film over the dielectric layer. Successively, a second silicon source gas at a second flow rate is performed injecting into the reaction chamber to form a second polysilicon film over the first polysilicon film, wherein the second silicon source gas having a different growth rate than the first silicon source gas. A patterned photoresist layer is then formed on the second polysilicon film. After the patterned photoresist layer is formed, a dry etching process by way of using the patterned photoresist layer as a etching mask is performed to etch through in turn the second polysilicon film and the first polysilicon film till exposing to the dielectric layer. Finally, the photoresist layer is removed.