| 摘要 |
PURPOSE:To determine precision of a key pattern for mask alignment irrelevant to precision of positioning of the second mask by a method wherein the first protective mask to be used for formation of the concave type key pattern is made to survive, while the second protective mask is formed thereon. CONSTITUTION:An oxide film 11 to be offered for formation of the key pattern is adhered on a semiconductor substrate 10. Then a photo resist is adhered on the film 11, and out of the film thereof, the exposed part to light passed through the first exposing mask is removed to form the first protective mask 12. The part of the film 11 is removed according to the pattern (key pattern) of the mask 12, etc. A photo resist 14 is adhered on the whole surface containing the key pattern regions 13. The region containing the key pattern regions 13 and excluding the region to be formed with an element is exposed using the second exposing mask, and the exposed region is removed to form the second protective mask. The regions 13 are removed in the concave type finally to form the key pattern. |
