| 摘要 |
PURPOSE:To reduce the extraction of an organic section, and to prevent environmental pollution by treating a resin on the inner surface of a through-hole by using a heated alkaline aqueous solution when smear in the through-hole formed in a multilayer circuit board is removed. CONSTITUTION:The aqueous solution of sodium hydroxide, potassium hydroxide or lithium hydroxide is heated and used as a liquid employed in a swelling process. A trace quantity of a surface active agent are added to the liquid, and the wettability of the liquid to the inwall of a through-hole 3 can also be improved. A multilayer board dipped in the liquid is washed by water or dipped in a de-smear treatment. Accordingly, the discharge of an organic section is reduced, thus preventing environmental pollution. |
