铜线性能及键合参数对键合质量的影响

为了提高铜线性能及其键合质量,采用拉力-剪切力测试仪、扫描电镜等研究了不同力学性能铜线及相应的键合参数对其键合质量的影响,分析了不同伸长率和拉断力、铜线表面缺陷、超声功率和键合压力对铜线键合质量的作用机制.结果表明:伸长率过小和拉断力过大会造成焊点颈部产生微裂纹,从而导致焊点的拉力和球剪切力偏低;表面存在缺陷的铜线其颈部经过反复塑性大变形会造成铜线表面晶粒和污染物脱落而出现短路和球颈部断裂;键合过程中键合压力过大能够引起的焊盘变形,同时较大的接触应力引起铝层溢出;过大的超声功率使键合区域变形严重产生明显的裂纹和引起键合附近区域严重的应力集中,致使器件使用过程中产生微裂纹而降低器件的使用寿命.

Effect of copper properties and bonding parameters on bonding quality

For improving the copper properties and bonding quality,the influence of different elongation,tensile strength,defects of copper surface,bonding power and bonding force on bonding quality is researched by pull strength-shear strength and scanning electron-microscopy(SEM).The results show that the small elongation and high tensile strength can cause micro-crack,and the bonding strength and shear strength are too low.The repeated large plastic deformation will cause copper surface chip and contamination falling and cause short circuit and crack.In bonding process,large bonding force can cause pad deformation,and high contact force can cause aluminum layer overflow.And the bonding area would deform and crack because of stress concentration caused by high bonding power,which would generate micro-crack in the using process and reduce the life of device.