| 摘要 |
PROBLEM TO BE SOLVED: To suppress warpage and the occurrence of defects by carrying out etching by high-frequency output using a prescribed photoresist film as a mask in an atmosphere of a gaseous mixture of gaseous CF4 or CHF3 and gaseous hydrogen in a specified mixing ratio. SOLUTION: A quartz glass substrate 11 is subjected to high velocity revolution and a photoresist film 12 is spirally exposed and developed in such a way that a DVD format signal is formed as pits 16. After sufficient evacuation, gaseous CHF3 and gaseous hydrogen are introduced in a mixing ratio of 2:1 and etching is capried out by supplying high-frequency power. Prescribed pits 13 are formed in the quartz glass substrate 11 using the photoresist film 12 as a mask to obtain the objective glass master disk 20. A nickel layer 14 by sputtering and a nickel layer 4 by electroforming are successively formed on the face of the glass master disk 20 with the pits 13 and the resulting nickel master 15 is peeled from the glass master disk 20 and subjected to prescribed treatment to obtain a stamper for forming an optical disk substrate.
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