PURPOSE: To inspect the positions and sizes of the defects within a stamper consisting of a conductive material by holding this stamper between two electrodes having end faces parallel with each other, deciding the electrostatic capacity of the desired point of the stamper and comparing this stamper thickness and the stamper thickness of the desired point obtd. by a film thickness measuring instrument.
CONSTITUTION: The distance between the electrodes 38a and 38b is assumed to be, for example, 0.3mm±1μm the stamper thickness to be about 200μm and the electrode area to be 1.0mm2. The material of the stamper is assumed to be Al2O3 and the specific dielectric constant thereof to be 9.34. The thickness of the stamper 39 is, thereupon, measured by the laser film thickness measuring instrument while the electrostatic capacity over the entire surface of the stamper 39 is measured. An approximate position where a 'blowhole' 40 presumably exists is specified by comparing the difference between the film thickness determined by the electrostatic capacity and the film thickness determined by a laser film thickness gage at this time. Further, the area of the electrodes 38a, 38b is converted to 3.14×10-16m2 and the exact position is specified. The stamper is mounted between rollers 2 and 3. A polycarbonate having 35000 average mol. wt. is used as a resin sheet material and the transfer of the ruggedness on the stamper to the sheet is possible.
YASHIMA MASATAKA
YUASA TOSHIYA
SANTO TAKESHI
