| 摘要 |
PURPOSE:To easily obtain a flattened structure by method wherein a non-doped polysilicon layer is formed on the semiconductor substrate on which a high density impurity source thin film pattern is formed, and after the impurity of the base pattern is selectively thermodiffused on the polysilicon layer, impurity-doped polysilicon is selectively removed by etching. CONSTITUTION:An As-doped polysilicon film 12 is formed on a semiconductor substrate 11, an etching is performed on the As-doped polysilicon film 12 using the photoresist pattern 13 formed on the film 12, and an As-doped polysilicon pattern 12a having the prescribed form is obtained. When a heat treatment is performed after a non-doped polysilicon film 14 has been formed on the semiconductor substrate 11, As is diffused very quickly in normal direction on the substrate 11, and an As-doped polysilicon film 15, which is in high fidelity for the base pattern 12a, is formed. Then, the As-doped polysilicon film 15 is selectively removed using an etching method having high selectivity such as a Cl2 plasma etching method, for example, at the etching temperature of 250 deg.C. |
