公开(公告)号：US20170342566A1

公开(公告)日：2017-11-30

申请号：US15537963

申请日：2015-09-17

Applicant: MEC COMPANY LTD.

Inventor： Yuko SHIBANUMA ,  Tatsuya GODA ,  Jojiro NIGORO ,  Tomoko ICHIHASHI ,  Keisuke JOKO ,  Takahiro YAMADA ,  Tsuyoshi AMATANI

IPC: C23C18/16 ,  H05K3/18 ,  H05K3/26

CPC classification number: C23C18/1689 ,  C23C18/1834 ,  C23C18/54 ,  H05K3/187 ,  H05K3/24 ,  H05K3/26 ,  H05K2203/072 ,  H05K2203/0789

Abstract: The invention relates to a washing solution for a tin plating film after electroless tin plating and before water washing. The invention also relates to a method for forming a tin plating film, the method includes a step of washing step using the washing solution. The washing solution according to the present invention is an acidic aqueous solution containing an acid, a complexing agent, a stabilizer and a chloride ion. The washing solution has a chloride ion concentration of 2 wt % or more, and a tin concentration of 0.5 wt % or less. The washing solution according to the present invention has good washing property for a tin plating film surface, and allows a tin plating film to easily maintain its properties. In addition the washing solution causes little influence on a tin plating film surface even when continuously used and is excellent in temporal stability.