LAYERED STRUCTURE AND PHOTOSENSITIVE DRY FILM TO BE USED THEREFOR

摘要

In a layered structure having at least a substrate and a photosensitive resin layer or cured film layer formed on the substrate and containing an inorganic filler, the content of the inorganic filler in the photosensitive resin layer or cured film layer is low on the side contacting the substrate and high on the surface side away from the substrate, so that a linear thermal expansion coefficient of the photosensitive resin layer or cured film layer as a whole is maintained as low as possible. Preferably, the inorganic filler content in the layer gradually increases continuously obliquely or stepwise from the side contacting the substrate to the surface side away from the substrate. A photosensitive dry film containing the above-mentioned photosensitive resin layer is suitable for use as a solder resist or an interlayer resin insulation layer of a printed wiring board.

主权项

1. A layered structure, comprising:
a substrate; and a photosensitive resin layer or cured film layer formed on the substrate and including an inorganic filler, wherein said photosensitive resin layer or cured film layer includes the inorganic filler at a lower content in a side contacting said substrate than in a surface side away from said substrate, the inorganic filler in the photosensitive resin layer or cured film layer on the surface side away from the substrate comprises at least one of Mg and Al, and a cured product of the photosensitive resin layer or cured film layer on the surface side away from the substrate exhibits a linear thermal expansion coefficient of 15×10−6/K to 35×10−6/K.