The invention discloses a
browning method for improving the interlayer bonding force of a
printed circuit board and belongs to the technical field of circuit boards. The
browning method comprises thefollowing steps S1, of cleaning, putting a
copper foil in a cleaning solution I for soaking for 3-5 min, adding a cleaning solution II, continuing soaking for 3-5 min, then sequentially putting the
copper foil in
hydrogen peroxide and
ethanol for soaking for 2-3 min, and then
drying the
copper foil with
nitrogen; S2, presoaking, putting the cleaned
copper foil into a presoaking solution, and carrying out
ultrasonic oscillation for 3-5 minutes; S3,
browning, namely browning the presoaked
copper foil in a browning tank in which browning liquid is stored; and S4, washing, putting the browned
copper foil into deionized water, washing with the water, and
drying with
nitrogen. The method is advantaged in that after browning, a sample plate shows good anti-stripping performance, and the strippingstrength is as high as 0.95 Kg / cm; thermal performance test is carried out, respectively six times of
tin immersion are carried out, 100 times of cold and hot
impact circulation and six times of
reflow soldering test on the laminated sample are carried out, that the
test sample has no bubbling, layering or plate explosion phenomenon is observed, and the interlayer bonding force is strong.