Na_2SO_4電解酸化水を用いたリードフレーム用銅鉄合金の表面酸化皮膜の除去

摘要

This paper describes the elucidation about the removal of surface oxidation layer of copper iron alloy for lead frame after heating processing using Na_2SO_4-electrolyzed oxidizing water (It abbreviates as Na_2SO_4 EO water). First, the etching characteristics of Na_2SO_4 EO water against the surface of copper iron alloy for lead frame was clarified using H_2SO_4 solution and NaCl EO water for comparative immersion experiments. The results showed that as for the etching efficiency on copper iron alloy, Na_2SO_4 EO water was superior to H_2SO_4 solution, while inferior to NaCl EO water. Also, Na_2SO_4 EO water more uniformly to the composition element of copper iron alloy by the etching compared with H_2SO_4 solution. As for the relationship between immersing time and etching speed, Na_2SO_4 EO water is same as NaCl EO water. Next, as for test pieces after heating processing, it did the surface oxidation layer removal experiment by the immersion. The results show that Na_2SO_4 EO water doesn't pollute the test pieces surface compared with NaCl EO water and it is possible to apply to the surface oxidation layer removal process.%リードフレームはCPUとプリント基板を接続する半導体パッケージの一種類であり，その基材は主に銅合金おょぴ鉄とニッケル系の合金を使用している.銅合金において銅に鉄あるぃはニッケルが少量に含有している鉄系，ニッケル系の銅合金があり，それぞれ機械的強度とプレス加工特性に優れている.リードフレームの製造プロセスにおいて，まず，プレス加工などにより形状を形成する.また，リードフレームの形状精度を保っために，プレス加工後，熱処理によって加工残留応力を除去しなければならない.そのあと，CPUとの接続信頼性を高めるために，ステージ部およびインナーリード先端部などに銀めっきを施す工程に入る.