| 摘要 |
PURPOSE:To increase a space factor extremely by forming photo-resists on the main surface of comparatively thin metallic foil to a wiring figure shape reverse to a desired coil pattern and thickly projecting conductive metallic layers on exposed metallic foil. CONSTITUTION:A negative type photo-resist is applied on both the surface and back of comparatively thin copper foil 4, and photo-resist layers 5 are formed on one main surface in a reverse wiring figure so that copper foil is exposed to a desired coil pattern shape. A photo-resist layer 5' applied on the back is not shaped according to a pattern. First conductive metallic layers 6 are attached thickly only on the surface of the exposed metallic foil through electroplating. An insulating resin layer 7 is formed by using epoxy resin, etc., and the resist layer 5' and copper foil 4 are removed. The exposed first conductive metallic layers 6 are electrolytic-copper plated to pile up metallic copper, and second conductive metallic layers 6' are formed in the same thickness as the first conductive metallic layers 6. |
