Electromagnetic shielding sheet and method of producing the same

Abstract

A netlike metallic foil 11′ and a transparent substrate film 14 are laminated with an adhesive layer 13. The adhesive-layer 13-side surface of the metallic foil 11′ may be formed with a darkening layer 12. The roughness of the adhesive-layer 13-side surface (lower surface) of the metallic foil 11′ is preferably such that the maximum height Rmax be more than 0 and less than 4 μm, more preferably more than 0 and 2 μm or less. As long as the maximum height Rmax of this surface of the metallic foil 11′ falls in the above-described range, the adhesive layer never contains air bubbles in such sizes that reflectance is adversely affected. Further, the roughness of the surface (upper surface) of the metallic foil 11′, opposite to the adhesive-layer 13-side surface, is preferably such that the arithmetic mean roughness Ra is in the range between 0.02 μm and 1 μm. As long as the arithmetic mean roughness Ra of this surface of the metallic foil 11′ is in the above range, it is possible to efficiently conduct vacuuming to bring, into close contact, a photosensitive resin layer and a photomask in sheet form placed on the photosensitive resin layer, before effecting the pattern-wise exposure of the photosensitive resin layer.

Dependencies are inferred from the claim text.