Patent ID: 6986980

Claim:
A method of producing a liquid discharge head comprising the steps of: (a) forming a pattern of removable resin on a liquid flow path forming portion on a substrate having a liquid discharge energy generation element, wherein said pattern is formed by (1) forming on the substrate a first positive photosensitive material layer for photosensitizing by ionizing irradiation of a first wavelength band in a crosslinked state and forming a lower layer composed of a crosslinked positive photosensitive material layer by heat treating this positive photosensitive material layer; (2) forming on the lower layer an upper layer composed of a second positive photosensitive material for photosensitizing by ionizing radiation of a second wavelength band to thereby obtain a two-layered structure; (3) forming the upper layer with a desired pattern by irradiating the ionizing radiation of the second wavelength band to a predetermined portion of the upper layer of the two-layered structure and removing only the irradiated area of the upper layer by development treatment; and (4) forming the lower layer with a desired pattern by irradiating the ionizing radiation of the first wavelength band to a predetermined portion of the lower layer exposed by the pattern forming of the upper layer and conducting a development treatment, wherein the first positive photosensitive material layer includes a ternary copolymer having a primary component composed of methyl methacrylate, and methacrylic acid as a thermally crosslinkable factor and another factor for extending a sensitivity region relative to the ionizing radiation; (b) applying and hardening a resin coating layer on the substrate to coat the pattern; (c) exposing and hardening the resin coating layer and conducting a development treatment to form liquid discharge ports therein; and (d) dissolving and removing the pattern.