| 摘要 |
PURPOSE:To manufacture multilayer boards which do not practically have pink rings, by providing an aftertreating chamber between an exit screening means and an ejecting part, and practically making the aftertreating chamber an inactive gas atmosphere containing a trace of oxygen. CONSTITUTION:An internal-layer board having a minute uneven film of copper oxide formed on the surface of printed wiring copper foil and dried are fed to a feed table 1, and conveyed to a specified position by a conveyor belt 21 on the left side of a reducing chamber 2 via an entrance screening seal 11. Then they are put on an up-and-down type circulating transfer frame 23 rising, and transferred upward. And vapor reduction is performed in a reducing gas atmosphere. This is an atmosphere where reducing gases such as hydrogen, hydrogen oxide, etc., and other gasifiable reducing compounds, a hydrazine gas for example, exist. Vapor-reduced internal layer boards are used for multi- layer lamination forming and made into multilayer shielding boards having copper foil on both sides. This makes it possible to obtain multi-layer printed wiring boards without pink rings. |
