| 摘要 |
PURPOSE:To prevent the occurrence of errors, by displaying always a positive or negative for various dimensions of a mask to be checked larger or smaller than a comparison reference mask respectively to make it unnecessary that the worker discriminates the sign. CONSTITUTION:The coordinate value of a moving table 30 is set to zero through a moving table coordinate measurer 41 when a reference position set input switch 35 of a display circuit 37 for fine adjustment quantity is depressed, and this coordinate value is positive when the moving table 30 is moved to the right, and it is negative when the moving table 30 is moved to the left. When the sign of the coordinate value of the moving table 30 is negative, the error is measured with chips at the righr end; and when a reference mark image 17 of a mask 15 to be checked is moved slightly to the left and is coincident with a reference mark 13 of a reference mask 11, a display circuit 37 displays a positive because the mask 15 is larger than the reference mask 11. Similarly, when the reference mark image 17 of the mask 15 is moved to the right, the circuit 37 displays a negative because the mask 15 is smaller than the reference mask 11. When the sign of the coordinate value of the moving table 30 is positive, the relation shown in table 1 is true, and thus, the burden of the worker is reduced to prevent errors. |
