Konishiroku Photo Industry Co., Ltd.

Kunio Sakurai

Tadashi Kojima

Hiroshi Ito

Takashi Nozaki

Hiroshi Itoh

Recently, there has been the tendency to increasingly use optical machinery and devices which utilize optical parts made of synthetic resin. Since an antireflection coating film for these synthetic resin optical parts is high in adhesive strength and is hard, it is advantageous to use silicon oxide. Particularly, silicon monoxide (SiO) varies in refractive index by varying the evaporation condition, and therefore, it is possible to make use of such properties to produce a multi-layered antireflection coating film from a single evaporation material by varying the evaporation conditions.

Antireflection optical coating

In a two or three anti-reflection coating, a .lambda..degree./2 layer is replaced by a composite layer.

Anti-reflective coating for a transparent substrate

The mask blank is provided with a transparent coating layer interposed between a transparent substrate and a mask metal layer. The transparent coating layer is made of material which is resistant to an etching solution.

Mask blank and mask

The photomask blank comprises a transparent substrate, a chromium film directly formed on the substrate and having a thickness of less than 15 m.mu., an intermediate layer formed on the chromium film and containing chromium oxide and a metal mask layer made of chromium and formed on the intermediate layer. The intermediate layer comprises a single chromium oxide film or a composite layer of a chromium oxide film and a pure chromium film or a mixture of chromium and chromium oxide. The photomask is prepared by etching the chromium film, the intermediate layer and the mask layer of the photomask blank described above.

Photomask blanks and photomasks prepared therefrom

The photomask blank comprises a transparent substrate, a first chromium film formed on the substrate by sputtering, a second chromium film formed on the first chromium film by vacuum evaporation and a chromium oxide film by vacuum evaporation. The relative thickness of the two chromium films and the chromium oxide film is adjusted to improve resolution of a pattern and to decrease reflectance.

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Hino, Japan

Kunio Sakurai