| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a mask positioning apparatus which is easy to manufacture and has a reduced positioning error. SOLUTION: The mask positioning apparatus is provided with a spinning holder, a wafer holder, a mask holder and four changeable balls of a known radius. Four conical grooves to hold the balls are respectively arranged on the rear face of the wafer holder and the upper face of the mask holder. Assuming that the radius of the ball is R, these conical holes are drilled to a depth of R×2 and an outer diameter of 2R×2 so that when the balls are inserted into the grooves, the wafer holder and the mask holder are precisely positioned.</p> |
