| 摘要 |
PURPOSE:To make the surface of an outer copper foil flat so as to improve the formation of a circuit in accuracy and to facilitate the boring of a hole by drill by a method wherein a resin layer containing glass powder is provided between a prepreg sheet and the outer copper foil. CONSTITUTION:A prepreg sheet 3 is oriented to an inner board 4, and then thermosetting epoxy resin containing a few % of glass powder whose diameter is 10mum or less is applied onto the prepreg sheet 3. Next, an outer copper foil 1 is overlapped with the resin layer, which is heated and pressed to form a wiring board 10 provided with a resin layer 2. By this setup, the irregularities of the prepreg sheet 3 are prevented from being transferred onto the outer copper foil 1. Therefore, a circuit or a solder resist film formed of the copper foil 1 is precisely and accurately formed. Moreover, when a boring process is carried out using a drill, a hole can be bored at a proper position. |
