| 摘要 |
PURPOSE:To remarkably decrease or eliminate halos or pink rings by treating the copper foil face of an inner layer board with an acid reductant water solution containing zinc formaldehydesulfoxylate after oxidizing chemically its copper foil face and forming a black or brown copper oxide face. CONSTITUTION:After polishing and washing the copper foil face of an inner layer board, pre-etching (soft-etching and chemical polishing) is performed with a water solution containing copper chloride or ammonium persulfate. After that, for example, its face is oxidized at a temperature of 70-100 deg.C with chemicals consisting of 15g/l of sodium hydroxide (NaOH), 31g/l of sodium hypochlorite (NaClO2), and 15g/l of sodium phosphate (Na3PH4) and then, a brown or black inner layer board is purified. Subsequently, it is treated with an acid reductant water solution containing zinc formaldehydesulfoxylate and then, the washed and dried inner layer board is obtained. Further, treatment with the acid reductant water solution is performed on condition that the concentration of zinc formaldehydesulfoxylate is 5-30g/l, pH is 0.1-7.0, a treatment temperature is 40-80 deg.C, and time of treatment is 0.5-5 minutes. |
