钎料稀土相表面Sn晶须生长的研究

Study of tin whisker growth on RE-phase surface of solders

为了解对钎料可靠性影响极大的Sn晶须的生长机理，系统研究了钎料稀土相CeSn3、LaSn3及ErSn3表面Sn晶须生长的影响因素。结果表明：稀土相的氧化倾向与时效温度共同影响其表面Sn晶须的生长。室温时效条件下，在稀土相CeSn3与LaSn3表面易出现小尺寸的线状Sn晶须，直径为0．1～0．2μm，而在稀土相ErSn3的表面易出现大尺寸的杆状Sn晶须，直径可达1μm左右；150℃时效条件下，在稀土相ErSn3的表面易出现小尺寸的针状Sn晶须，而在稀土相CeSn3与LaSn3的表面不会出现sn晶须。

To understand the growth mechanism of tin whisker which greatly affect the reliability of solders, influencing factors of tin whisker growing on the surface of CeSn3, LaSn3 and ErSn3 phases of solders were investigated. The results indicate that the growth behaviors of tin whiskers on the surface of the oxidized RE-Sn phases are determined by both the oxidation tendency of the RE-Sn phase and the aging temperatures. During room temperature aging, small sized thread-like tin whiskers, whose diameter is 0.1 μm to 0.2 μm, form on the surface of CeSn3 and LaSn3 phases, however, large sized rod-like tin whiskers, whose diameter can reach up to about 1 μm, form on the surface of ErSn3 phase. During 150 ℃ aging, small sized needle-like tin whiskers form on the surface of ErSn3 phase, and on the contrary, tin whiskers are not found on the surface of CeSn3 and LaSn3 phases.