| 摘要 |
PURPOSE:To inexpensively remove the smear of a small-sized through hole in high quality by conducting part or all of a smear removing solution dipping under a specific reduced pressure environment in the manufacture of a multilayer printed wiring board. CONSTITUTION:In a smear removing device, a multilayer printed substrate 6 in which glass epoxy is employed as a base material and a small-diameter through hole 7 having 0.3 or less in diameter is opened is set to a substrate clamping jig 5. After a vacuum chamber 1 is sealed, the chamber 1 is evacuated by a vacuum pump 2 to 100Torr or less. Then, the substrate 6 is dipped in conc. sulfuric acid 4 by moving down the clamping jig 5, evacuated pressure is released after 1-5 seconds, and a multilayer printed substrate is completed by a known method. The pressure is recovered as below thereby to further reduce the volume of air bubbles, and the smear of the through hole can be removed without employing an expensive plasma apparatus. |
