| 摘要 |
PROBLEM TO BE SOLVED: To stably maintain an opening formed in an insulating resin layer with a desired diameter for a long time by reducing the illuminance drop of a discharge lamp for exposure having a bulb length that falls within a specific range by forming a photosensitive resin layer on a lower-layer conductor circuit and, at the same time, exposing the photosensitive resin layer to the light emitted from the discharge lamp. SOLUTION: A discharge lamp 7 for exposure has a bulb length of 90-250 mm and a bulb diameter of 90-150 mm. In such a bulb length of the lamp 7, the length can reduce the illuminance variations of between discharge lamps 7 and the illuminance drop of the lamp 7 resulting from foreign maters adhering to the internal surface of the bulb of the lamp 7 and assures the effect of the impurity removing material incorporated in the lamp 7. In the discharge lamp 7 of such and arrangement, the photosensitive reactions of a photosensitive resin, a resin for forming photosensitive solder resist, and a photosensitive dry film become appropriate and openings having desired diameters and wiring can be formed and stably maintained for a long time, because the variation of the exposing factor, such as the wavelength, illuminance, etc., of the light source is reduced regardless of the used time. |
