| 摘要 |
<p>PURPOSE:To simplify the process of impurity implantation when enlarging the concentration of the low-concentration impurity source and drain regions of one side of two film transistors of LDD structure more than that of the other. CONSTITUTION:A photoresist mask 43 is formed on a polysilicon film 41. Next, phosphorous ions are implanted in a certain low concentration into the polysilicon film 41 in one film transistor formation area, using a hard mask 47. Next, phosphorus ions are implanted in low concentration different from a certain into the polysilicon film 41 in the other film transistor formation area, using a hard mask 49. After this, the photoresist mask 43 is removed. In this case, the photoresist mask 43 can be used in common, so the photoresist mask formation process and its removal process can be reduced by one time. Next, another photoresist mask 52 is formed, and phosphorus ions are implanted in high concentration.</p> |
