| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a multilayer wiring board manufacturing method capable of improving a multilayer wiring board in dimensional accuracy and reducing production processes in number. SOLUTION: The formation of a viahole 17a and the flattening operation of the projection of an insulating film photosensitive varnish 7a are performed at the same time by carrying out an light exposure process, and a developing process by the use of a photomask which is so designed as to be composed of a light transmitting film 9, a 67% light transmitting film 11, a 20% light transmitting film 10, and a light shielding film 8 which are stacked up in this sequence for each of a flat 12, a slope 13, a protuberant flat 14, and a viahole forming predetermined point 15. By this setup, production processes can be reduced in number, and an exposure process can be reduced in frequency, so that a multilayer wiring board can be improved in dimensional accuracy.</p> |
