| 摘要 |
PURPOSE:To maintain quality of photomask in fixed high grade by using hard plate of appropriate pinhole density and by correct and rapid judgment and display on contrast ratio of negatives, at photo masking of semiconductor integrated circuit. CONSTITUTION:Irradiated light onto negatives is measured by standard signal light receiver and after amplified by amplifier, sent out output signal b which is attenuated by base plate transmission factor and apperture opening correcting circuit. Furthermore, light which is transmitted through negatives is measured by light receiver, amplified and sends out output signal a. Output signals a and b are compared by comparison treatment circuit and are indicated at display section putting out its ratio as pattern contrast ratio of photomask negative. |
