| 摘要 |
PURPOSE:To improve antioxidation without loss of adhesion strength and heat resistance of the adhering surface of an inner layer copper of a board by processing the circuit copper surface of an inner layer circuit board with copper oxide or cuprous oxide, then dipping it in specific acidic solution and then dipping it in chromium compound solution. CONSTITUTION:After a circuit copper foil surface of an inner layer circuit board is processed with copper oxide or cuprous oxide, it is dipped in acidic solution containing one or more of tertiary butylamine borane, trimethylamine borane, pyridine borane of reducing agents to reduce the copper oxide layer surface to be activated, and dipped in chromium compound solution to form a chromate film. The concentration of the solution containing one or more types of the tertiary butylamine borane, trimethylamine borane, pyridine borane is not particularly limited, but a more effect is expected by dipping at 20-50 deg.C for 1-5min in a range of 0.1-10%. Thus, in the case of lower concentration (higher concentration) therefrom, the dipping time may be increased (decreased) or its processing temperature may be raised (lowered). |
