| 摘要 |
The invention relates to a process and solution for chemically dissolving the electrochemically deposited Sn- Pb alloy, applicable for the fabrication of double-faced and multilayered printed circuits In a first step, the coarse Sn-Pb layer is disolved by immersion into a solution A for 1 - 3 minutes, in the second step, the atomic Sn-Pb interlayer is dissolved by immersing the circuit into the solution B based on FeCl 3, or into another solution C based on HNO 3, where the circuit can stay up to 45 s The solution A comprises water and nitric acid in a ratio of 3: 1 and 5 to 10 g/l hydroxylamine chlorohydrate The solution B comprises 95 l H 2 O, FeCl 3 in a concentration of 50 100 g/l, 1 % HCl, 20 to 40 ml/l sodium lauryl sulphate and 20 to 40 ml/l benzothiazole The solution C comprises water and nitric acid in a ratio of 4 : 1, 20 to 40 ml/l sodium lauryl sulphate and 20 -40 ml/l benzothiazole
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