Tin Whisker Formation on Electroless Tin Films Deposited on Lead-frame Alloys
Electroless Sn films have great potential in the lead-free age such as for high-density, fine-pitch, narrow soldering pad and bump interconnection applications. In the present work, electroless Sn were deposited onto lead-frame alloys (C194 and FeNi42). The microstructures of the electroless Sn films and tin whisker growth in thermal /humiditive chamber were investigated with scanning electron microscope and optical metallography. It was found that, in comparison with the FeNi42 substrate, the C194 substrate was more favorable for the deposition of electroless Sn coatings. The grain size in-creased with increase of the thickness of the Sn deposits. Within 45 min, autocatalytic activity still exists, which could keep the autocatalytic deposition of electroless tin on the C194 substrate. Tin whiskers growth was found only after 1000-hour exposure of the samples to the thermal-humiditive environment.
Ting Liu Yiqing Wang Dongyan Ding Klaus-Peter Galuschki Yu Hu Yihua Gong Ming Li Dali Mao
Institute of Microelectronic Materials & Technology, School of Materials Science and Engineering, Sh Siemens AG, CT, Siemensdamm50, D-13623 Berlin, Germany SMT Technology & Material, Corporate Technology, Siemens Ltd., China
国际会议
上海
英文
810-814
2011-08-08（万方平台首次上网日期，不代表论文的发表时间）