| 摘要 |
PURPOSE:To evaluate the pattern state of an emulsion mask by detecting the time interval between the peak value of the transmitted light signal at the rise or fall coincides the first threshold and does the second threshold with a vertical scanning at the end rim of the pattern. CONSTITUTION:The section of the light beam is made rectangle 5 in such a manner as to be lengthened vertical to the end line of the pattern 3. To reduce the width of the light beam from the light source, it is limited with the slit after magnified by lens system or the like. The pulses exceeding the output levels L1 and L2 close to the light transmission part and non-light transmission part are separately extracted through two comparators and inputted to an exclusive logic circuit to select the pulses at the height between the two levels which are counted with the pulses from the two levels which are counted with the pulses from the pulse power source through an AND circuit. This provides the time necessary to capture the beginning and the end of the blurring at the end of the pattern 3, thereby allowing the quantitative evalution of the state at the end of the emulsion mask. |
