| 摘要 |
PURPOSE:To enhance the accuracy in forming a resist pattern, in the method of forming contact holes in a semiconductor substrate, by decreasing the thickness of a thermally oxidized film on a base region by photoetching. CONSTITUTION:A base region 2 and a thermally oxidized film 3 are formed on a silicon substrate 1. Then, a hole 4 is formed by photoetching. Thereafter, a portion of the film 3 is further removed by photoetching. Then, an emitter region 5 is formed. At this step, a new thermally oxidized film 3' is formed, but the difference in thicknesses of films 3' and 3 is very small. Then, contact holes 6 and 6' are simultaneously formed through the films 3 and 3' by photoetching. Since the difference in thicknesses of the thermally oxidized films 3 and 3' are very small, light does not enter into the emitter region at the exposure, and a highly accurate resist pattern can be formed. |
