| 摘要 |
PURPOSE:To make it possible to form fine pores and enhance the density of wiring pattern by irradiating light to an insulation sheet exposed from an opening section formed on a metal foil when boring a through hole. CONSTITUTION:An organic insulation sheet 1 is processed by a laser L so as to form a through hole 5. This practice does not call for any wet process based on hydrazine or an alkali solution. Furthermore, if an opening section 4a of a metal foil 4 is miniaturized, it will be possible to form a fine hole 5. Therefore, no complicated process is required where a higher density pattern can be formed. The wiring patterns 2b and 4b are electrically connected by way of a through hole contact 6 by filling the hole in by electroless plating. |
