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|1. (WO2017153590) LEAD-FRAME STRUCTURE, LEAD-FRAME, SURFACE MOUNT ELECTRONIC DEVICE AND METHODS OF PRODUCING SAME|
|Applicants:||ATOTECH DEUTSCHLAND GMBH
|Title:||LEAD-FRAME STRUCTURE, LEAD-FRAME, SURFACE MOUNT ELECTRONIC DEVICE AND METHODS OF PRODUCING SAME|
In order to provide a more reliable and cost-efficient way of producing lead-frames or lead- frames structures which expose treated silver surfaces as well as to provide surface mount electronic devices using such lead-frames or lead-frames structures, a method comprising the following method steps carried out in this order is provided: (a) providing a lead-frame body structure having two main sides, said lead-frame body structure exclusively exposing a copper surface on each one of said main sides; (b) depositing a silver coating on at least one of said main sides, so that said at least one of said main sides at least partially exposes an untreated silver surface; and (c) electrolytically treating said untreated silver surface on said at least one of said main sides generated in method step (b) with a treatment solution containing at least one hydroxide compound selected from alkali metal hydroxides, alkaline earth metal hydroxides, ammonium hydroxides and mixtures thereof, wherein the lead-frame body structure is a cathode, thereby producing a lead-frame structure which comprises at least two lead-frame entities each one having two faces and at least partially exposing said treated silver surface; wherein said at least one of said two faces of at least one of said lead-frame entities either exclusively exposes said treated silver surface or wherein said at least one of said two faces of said at least one of said lead-frame entities partially exposes said treated silver surface and partially exposes said copper surface, wherein, on each one of said two faces of each one of said lead-frame entities which partially exposes said treated silver surface, the area of said copper surface is smaller than the area of said treated silver surface.