PURPOSE: To remove uneven aperture by defects micro dispersion of hole diameter so as to improve yield rate, regarding shadow masks on which electron beam passage holes are arranged with high accuracy with at minute pitches, by adding a specified sensitizer to a photosensitive agent.
CONSTITUTION: A photosensitive film 21 is formed by applying a photosensitive agent, which has photosensitive resin and a cross linking agent as its main ingredients, on the board face of a shadow mask blank 20, and drying it. A resist film is formed by baking a specified pattern onto this photosensitive film 21, and developing it, and then and electron beam passage hole is formed etching it. At that time, a photosensitive agent is used, in which a sensitizer which has the peaks of transmissivity at 360±10nm and 400±10nm and the transmissivity of 450nm of which is one-fifth or less this peak value is added by 30-160wt.% to the above cross linking agent (ammonium dichromate. Uranium (curve 29) may be preferably used as the above sensitizer.
TSUKAGOSHI HATSUO
GAMO YASUNORI
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