| 摘要 |
<p>PROBLEM TO BE SOLVED: To assure excellent heat resistance and electric insulation characteristic and set diameter of a through hole for interlayer connection to the predetermined value or less by forming a hole with carbonic acid gas laser processing using an insulation resin bonding sheet with copper foil formed by integrating previously the copper foil and insulation resin. SOLUTION: A bonding sheet 1 with copper foil is laminated to a printed wiring board 2 having completed circuit process with a hot press, a photosensitive dry film is laminated to a wiring board 3 laminating such bonding sheet 1 with copper foil, ultraviolet ray is radiated thereto via a mask pattern and the developed laminated wiring board 3 is etched to form a through hole to the copper foil A. Moreover, the carbonic acid laser beam 5 is applied, a hole is bored to the insulation resin layer B with the laser beam 5 having transmitted the through hole 4, and thereby a blind hole 6 reaching the printed wiring bard 2 under the aperture is formed. Thereby, a fine via hole of 100μm or less can surely be formed effectively.</p> |
