Abstract: According to this invention, a wiring board includes a conductive pattern formed from leads each of which is formed on an organic layer and has a thickness t larger than a width W.

Abstract: Projections are formed on front and back surfaces, respectively, of a thin-plate-like protective film at its widthwise opposite ends. Each of the projections is generally trapezoidal as viewed from an end surface side of the thin-plate-like protective film. Even if the projections are misaligned with respect to the projections when the thin-plate-like protective film is wound around a reel, part of a crown portion of each of the inner projections on an exteriorly located part of the thin-plate-like protective film abuts, via the widthwise opposite ends of base film of the tape-like structure, against part of a crown portion of the corresponding outer projection on an interiorly located part of the thin-plate-like protective film. This hinders the widthwise opposite ends of base film of the tape-like structure from being wavily deformed.

Abstract: Where the length LD of a resin film forming region is, for example, 3 times as long as the pitch of the sprocket holes of the base film, the resin coating is performed by using 6 nozzles, and where the length LD is, for example, 6 times as long as the pitch of the sprocket holes, the resin coating is performed by using 3 nozzles. As a result, the transfer distance of the base film transferred in a single resin coating process is 18 times as long as the pitch of the sprocket holes. It follows that it is possible to set constant the time for the base film to pass through the drying section even if the length LD of the resin film forming region differs.

Abstract: A flexible wiring board is provided which is made of a relatively thin polyimide film and, thus, can be bent easily. Therefore, the flexible wiring board can be bent easily in the vicinity of a semiconductor chip mounting region without forming slits for facilitating the bending in the film substrate. As a result, it is possible to decrease the length of that portion of the flexible wiring board which is positioned ahead of the semiconductor chip mounting region.