| 摘要 |
1508178 Etching RCA CORPORATION 2 May 1975 [22 May 1974] 18554/75 Heading B6J [Also in Division G2] A method of producing a line-width modulated surface relief pattern from an amplitude modulated surface relief pattern comprises (a) coating a substrate 12 with a photoresist 10, (b) exposing the photoresist to a light intensity pattern, (c) developing the photoresist into a continuously variable amplitude modulated surface relief pattern 18, 20 which reveals the substrate surface 24, 26 as a function of the light intensity pattern, (d) etching the substrate to form a wave grating of substantially uniform depth and rectangular cross-section 28, 30 and (e) removing the remaining photoresist. The substrate may be glass coated with Cr, with Cr and Mo or with iron oxide. The etchants specified for the metal, iron oxide and glass are HNO 3 /H 2 SO 4 /water; ferric chloride/HCl; ferrous chloride/HCl/water and HF.
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