| 摘要 |
PURPOSE:To regenerate an electroless plating soln. when the specific gravity is increased during use, by introducing the plating soln. into a cooler so as to successively remove org. oily foreign matter and sodium sulfate. CONSTITUTION:When the specific gravity of an electroless plating soln. for forming a plated copper circuit on a wiring board is increased during use, the plating soln. is introduced into a cooler, where org. oily foreign matter extracted from the board during plating is first separated and removed. By- product sodium sulfate accumulated in the plating soln. is then crystallized and removed. The electroless plating soln. regenerated in the cooler at low temp. is poured into a tank contg. a plating soln. overflowed during operation to drop the temp. by <=about 5 deg.C. The resulting soln. is introduced into a plating tank after mixing with sodium hydroxide for adjusting the pH and formalin for increasing the activity. Thus, the spent electroless plating soln. can be regenerated and utilized. |
