电子元件与材料
電子元件與材料
전자원건여재료
ELECTRONIC COMPONENTS & MATERIALS
2015年
6期
74-77
,共4页
何洪文%曹立强%聂京凯%朱承治
何洪文%曹立彊%聶京凱%硃承治
하홍문%조립강%섭경개%주승치
焦耳热%电迁移%晶须%应力释放%无铅焊点%电流密度
焦耳熱%電遷移%晶鬚%應力釋放%無鉛銲點%電流密度
초이열%전천이%정수%응력석방%무연한점%전류밀도
Joule heating%electromigration%whisker%stress release%lead-free solder joint%current density
研究了Cu/Sn3.8Ag0.7Cu/Cu一维焊点在电流密度为5×103A/cm2、环境温度为100℃作用下晶须的生长机理。研究结果表明,通电300 h后,在Cu/Sn3.8Ag0.7Cu/Cu焊点的阳极界面出现了一些小丘,而在焊点的阴极出现了一些裂纹;通电500 h后,焊点阴极界面的裂纹进一步扩展,而且在裂纹处发现了大量纤维状Sn晶须,其长度超过10μm;继续通电达到700 h后,Sn晶须的数量没有增加,同时停止生长。由于电迁移的作用,金属原子在电子风力的作用下由焊点的阴极向阳极进行了扩散迁移,进而在阴极处形成裂纹。随着裂纹逐渐扩展,导致该区域处的电流密度急剧增大,焦耳热聚集效应明显,为了释放应力,形成了纤维状的晶须。
研究瞭Cu/Sn3.8Ag0.7Cu/Cu一維銲點在電流密度為5×103A/cm2、環境溫度為100℃作用下晶鬚的生長機理。研究結果錶明,通電300 h後,在Cu/Sn3.8Ag0.7Cu/Cu銲點的暘極界麵齣現瞭一些小丘,而在銲點的陰極齣現瞭一些裂紋;通電500 h後,銲點陰極界麵的裂紋進一步擴展,而且在裂紋處髮現瞭大量纖維狀Sn晶鬚,其長度超過10μm;繼續通電達到700 h後,Sn晶鬚的數量沒有增加,同時停止生長。由于電遷移的作用,金屬原子在電子風力的作用下由銲點的陰極嚮暘極進行瞭擴散遷移,進而在陰極處形成裂紋。隨著裂紋逐漸擴展,導緻該區域處的電流密度急劇增大,焦耳熱聚集效應明顯,為瞭釋放應力,形成瞭纖維狀的晶鬚。
연구료Cu/Sn3.8Ag0.7Cu/Cu일유한점재전류밀도위5×103A/cm2、배경온도위100℃작용하정수적생장궤리。연구결과표명,통전300 h후,재Cu/Sn3.8Ag0.7Cu/Cu한점적양겁계면출현료일사소구,이재한점적음겁출현료일사렬문;통전500 h후,한점음겁계면적렬문진일보확전,이차재렬문처발현료대량섬유상Sn정수,기장도초과10μm;계속통전체도700 h후,Sn정수적수량몰유증가,동시정지생장。유우전천이적작용,금속원자재전자풍력적작용하유한점적음겁향양겁진행료확산천이,진이재음겁처형성렬문。수착렬문축점확전,도치해구역처적전류밀도급극증대,초이열취집효응명현,위료석방응력,형성료섬유상적정수。
Cu/Sn3.8Ag0.7Cu/Cu solder joint with current density of 5×103A/cm2 at 100℃ was investigated. Results show that after current stressing for 300 h, some hillocks occur at the anode interface and some cracks appear at the cathode interface. As the electromigration test goes on for 500 h, the cracks propagate along the cathode interface. Furthermore, a large quantity of Sn whiskers appears at the crack region, whose lengths are beyond 10μm. As the current stressing reaches 700 h, the total whisker quantity dosen’t increase, and stop growing. Due to the electromigration, the metal atoms migrate from the cathode side to the anode side by the electron wind force, resulting in the crack formation at the cathode interface. Therefore, the current density at the crack region increases, leading to much more Joule heat accumulation, to release the stress, some whiskers are formed in this crack region.