关键词: 铜引线键合, 超声波, 塑性形变, 裂纹

Abstract: In electronic packaging, due to the high hardness of Cu copper wire and the complex structure of 0.18 μm technology chip, one of the serious quality defects is cracks that sometimes can be found on the dielectric insulation layer of chip after Cu wire bonding. Based on the 0.18 μm technology chip, the crack formation and elimination method under different Cu wire bonding parameters were studied experimentally on ASM wire bonding machine.The crack morphology under the existing Cu wire bonding parameters was analyzed and used as a reference for comparison. Then, the main parameters causing the crack were obtained through the design of experiment (DOE). Finally, the way to eliminate the crack was studied by means of fine-tuning different parameters successively. Collecting data type included the Cu ball diameter, wire pull strength, ball shear strength, intermetallic compound coverage and crack number, etc. The results show that: 1) large plastic deformation promotes the formation of cracks; 2) ultrasonic output power is the main influencing parameter of crack generation, including parameters of standby power, pre-base power, base power; 3) at the Cu wire bonding contact stage, when the search speed, threshold and initial force are large, they are conducive to crack elimination; 4) at the pre-bonding with Cu wire stage, the setting of parameters such as pre-base scrub power, pre-base scrub cycle, and pre-base scrub amplitude should not be too large , which is not conducive to the elimination of cracks, but promotes the rapid growth of the number of cracks. Therefore, the way to eliminate the crack of 0.18 μm technology chip in Cu wire bonding is obtained through experimental research, which can provide reference for correlated Cu wire bonding technology and product production.

Key words: Cu wire bonding, ultrasonic, plastic deformation, crack