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研究了焊点高度为10μm的Cu/Sn/Cu微焊点接头在110℃下分别进行200、400、600、800h等温时效后界面CuSn金属间化合物的显微组织及剪切强度的演变。结果表明,随着时效时间延长,界面的金属间化合物由初始的扇贝状Cu-_6Sn_5组织逐渐演变为层状的Cu_3Sn和Cu_6Sn_5组织,并且界面金属间化合物在时效作用下不断消耗钎缝中的β-Sn向焊点中部生长,800h时效后焊点组织完全被Cu_3Sn和Cu_6Sn_5金属间化合物所取代;另外,随着时效时间的延长及界面金属间化合物的演变,焊点的剪切强度不断提高,其中当时效时间达到400h时,两端界面金属间化合物发生部分接合,剪切强度增幅较大;800h时效后试样的剪切强度为最大值。断口形貌分析表明,随着时效时间延长,焊点的断裂机制由韧性剪切断裂演变为脆性剪切断裂。
The microstructures and shear strengths of CuSn intermetallic compounds at 200 ℃, 400h, 600h and 800h after aging at 110 ℃ were studied for the Cu / Sn / Cu micro-joints with a solder joint height of 10μm. The results show that the interface intermetallic compounds gradually evolve from the initial scallop Cu-6Sn 5 to the layered Cu 3 Sn and Cu 6 Sn 5 as the aging time prolongs, and the interface intermetallic compounds continuously consume the β -Sn to the middle of the solder joint. After 800h aging, the solder joints were completely replaced by Cu3Sn and Cu6Sn5 intermetallic compounds. In addition, as the aging time and intermetallic compounds evolved, the shear strength of the solder joint increased continuously, When the aging time reached 400h, intermetallic compounds at both ends of the joint part of the joint, a sharp increase in shear strength; 800h after aging specimen shear strength maximum. The fracture surface morphology analysis shows that the fracture mechanism of the solder joints evolves from ductile shear fracture to brittle shear fracture with the aging time prolonging.