| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a diffraction optical element permitting to improve an optical efficiency by reducing the number of dry etching processes, and lessening the occurrences of concave parts and pillars as far as possible even when registration accuracy among each dry etching processes does not satisfy a required level. SOLUTION: Concerning each pillar or each concave part which is a cause of an optical efficiency impediment determined to arise from mis-registration of a dry etching area among dry etching processes and to be generated at the boundary part of one differential inter-stage of depth level, a grade as the optical efficiency impediment factor is weighted with 1 when the height of the pillar or the depth of the concave part is a unit stage widthδ; when the height of the pillar or the depth of the concave part is m (m is an integer of 2 or larger) times as large as the unit inter-stageδ, the factor is weighted withαm as specified; such a combination of the dry etching processes is obtained, as the summation of all the weights of each pillar or each concave part serves as a minimum; and the processing is carried out with the combination of the dry etching processes obtained, to manufacture the diffraction optical element. COPYRIGHT: (C)2005,JPO&NCIPI
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