| 摘要 |
PURPOSE:To reduce the occupying area of an integrated circuit element, and to improve the saturation characteristics of an element for a small signal by providing a process in which a recessed section for forming a well region in a high withstanding-voltage element is shaped and a recessed section for forming a well region for the small signal unnecessitating high withstanding voltage is shaped. CONSTITUTION:A resist film 6 is removed, and a recessed section 9 for shaping a well region in a high withstanding-voltage element is bored into a semiconductor substrate 1 through the removed recessed section 8. A recessed section 10 for forming a well region in an element for a small signal is bored to an oxide film 2 just under a window 5 corresponding to a well-region prearranged section in the element for the small signal in an silicon nitride film 3 while using the window 5 as a mask. A recessed section 11 in which the well region for the element for the small signal is shaped is formed into the semiconductor substrate 1 through the recessed section 10. Accordingly, the recessed section 9 for shaping an element region in the high withstanding-voltage element and the recessed section 11 for forming an element region in the element for the small signal can each be formed in desired size into predetermined regions in the semiconductor substrate 1. |
