Pbフリーはんだ用Sn-Ag合金めっき
1998 年 49 巻 1 号 p. 73-77
詳細
1998 年 49 巻 1 号 p. 73-77
We studied the effects of electrodeposition conditions on Sn-Ag alloy composition and current efficiency in Pb-free solder plating employing a new pyrophosphate-iodide bath. We also investigated the morphology, phase structure, thermal characteristics and solderability of electroplated Sn-Ag alloy films. Ag content in deposits decreased with increasing current density during both agitation and nonagitation, Sn-Ag electroplated films containing between 2.0 and 20.0 at% silver consisted of β-Sn and the ε phases, β-Sn phase orientation in electrodeposited Sn-Ag alloy films became random with increasing ε phase content. The melting point, i.e., the temperature at which melting first occurred, of electroplated Sn-Ag alloy films was 221°C. Wetting time of electroplated Sn-Ag alloy films became minimum at a near Sn-Ag eutectic composition and was not affected by thickness from 0.5 to 10μm.
