無鉛焊點(diǎn)拉伸性能的影響
(華南理工大學(xué) 機(jī)械與汽車工程學(xué)院，廣州 510640)
摘 要: 采用掃描電子顯微鏡(SEM)、能譜儀(EDS)和微拉伸實(shí)驗(yàn)，研究Cu/Sn-3.0Ag-0.5Cu/Cu對(duì)接焊點(diǎn)在不同電遷移時(shí)間下陽極、陰極界面金屬間化合物(IMC)的生長演變規(guī)律及焊點(diǎn)抗拉強(qiáng)度的變化，同時(shí)對(duì)互連焊點(diǎn)的斷口形貌及斷裂模式進(jìn)行分析。結(jié)果表明：在電流密度(J)為1.78×104 A/cm2、溫度為373 K的加載條件下，隨著加載時(shí)間的延長，焊點(diǎn)界面IMC的生長呈現(xiàn)明顯的極性效應(yīng)，陽極界面IMC增厚，陰極界面IMC減薄，且陽極界面IMC的生長符合拋物線規(guī)律；同時(shí)，互連焊點(diǎn)的抗拉強(qiáng)度不斷下降，焊點(diǎn)的斷裂模式由塑性斷裂逐漸向脆性斷裂轉(zhuǎn)變，斷裂位置由焊點(diǎn)中心向陰極界面處轉(zhuǎn)移。
關(guān)鍵字: 界面化合物；電遷移；極性效應(yīng)；抗拉強(qiáng)度；斷裂
tensile properties of Sn-3.0Ag-0.5Cu lead-free solder joint
（School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640，China）
Abstract:The butting solder joint of Cu/Sn-3.0Ag-0.5Cu/Cu was used to investigate the evolution of the intermetallic compound (IMC) at the anode and cathode interface, and the degradation of the tensile strength of solder joint with different electric current stressing times, by a scanning electron microscope equipped with energy dispersive spectrometer and micromechanical test. Meanwhile, the fracture of solder joint was also evaluated. The results show that under the condition of J=1.78×104 A/cm2 and T=373 K, with increasing the current stressing time, the growth of interfacial IMC presents an obviously polarity effect, the IMC thickens at the anode surface and thins at the cathode surface, and the growth of the interfacial IMC at anode follows a parabolic growth rule. The ultimate tensile strength of the solder joint declines continuously. The fracture mode gradually transforms from plastic fracture to brittle fracture, and the fracture position transfers from the middle to the cathode interface of solder joint.
Key words: intermetallic compound; electromigration; polarity effect; tensile strength; fracture
