| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical master disk having grooves of trapezoid-shaped sections in which land parts become flat even in the case of a narrow track pitch. SOLUTION: Flat parts can be provided at the land parts 13 even in the case of grooves 12 having a narrow track pitch Tp, which is within the range of 0. 6 to 1.0μm, by having the steep grooves 12 in which the track pitch Tp is within the range of 0.6 to 1.0μm, the half-value width Th is within the range of 0.2 to 0.6μm, the tilt angleθat the half-value width thereof is within the range of 71 to 90 deg.. Thus, the intensity of exposed light of a second layer at an area close to a first layer is increased to make the slope steep by the use of a resist disk having the first layer by a transparent film set to a film thickness which intensifies the reflectivity of the exposed light thereof with respect to a film thickness of the second layer and the wavelength of the exposed light between the second layer and the glass substrate by a photoresist.
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