| 摘要 |
A semiconductor device with an alignment mark has a first well of a first conductivity type formed on the entire surface of a semiconductor substrate, a second well of a second conductivity type opposite to the first conductivity type formed within a desired region of the first well, and an oxide film formed on said first well and said second well, the first well having a higher impurity concentration than that of the semiconductor substrate, the depth of the first well being greater than that of said second well, and the oxide film having a step-wise alignment mark at a boundary between the first well and the second well.
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