| 摘要 |
Metal masked photographically for etching tends to be undercut round the edges of the mask, depending upon the length of the etching period. Commonly the mask is made too large by an amount equal to the expected undercut, so that the finished pattern will be correct to size. The new method follows the outline of the mask with a conductor of the same metal as the workpiece, having a horizontal thickness equal to the difference between the desired width of pattern and the expected undercut width. Sudden increase in the resistance of the conductor means that metal of that thickness has been etched away, i.e., the expected amount of undercut has taken place.
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