Study On The Preparation And Ball Bonding Process For The High-Performance Copper Bonding Wire

With the application of dedicated equipment on copper wire bonding and improvement of the bonding process,copper wire has good mechanical properties, low-cost,higher conductivity advantages,It is an ideal material for bonding to replace the alloy wire and aluminum - silicon wire.Therefore,It is an inevitable trend that a high-density,low-arc welding of high-performance copper wire bonding has been widely accepted by the marketIn this paper,sums up the reasons for the ordinary single-crystal copper in the process of drawn filaments caused disconnection,the quality of copper billets and follow-up process of the drawing are the main factors causing disconnection;after the equipment and techniques to improve,we evaluate single crystal copper surface quality,test chemical composition and performance;use a reasonable process to draw the high purity single crystal copper rodsⅡto evaluate the performance of it can pull,and also were drawn to high-performance copper bonding wire annealing, the hard state of natural aging,soft-state natural aging,homogeneity test,the ball bonding tests.From the study,it is found that surface of fine wire without defects after the use of improved equipment and technology,the test results indicates the chemical constituents is not less than 99.999%,and the performance index is also significantly higher than ordinary purity single crystal copperⅠ.In the experiment,high purity copper rods in the drawn filaments show that the line rate is minimal,inφ0.03 -φ0.023mm drawn range,the line rate of high purity single crystal copper rodsⅡare 3 times lower than the ordinary copper rods,and also eliminate the axial surface abrasions,triangular mouth and embedded surface defects.Forφ0.023mm single crystal copper bonding wire,the break load and elongation were excellent at heat treatment in 425℃and 1.2s.After natural aging,soft-state high-performance copper bonding wire show that mechanical properties and electrical properties are relatively stable,and no obvious signs of oxidation on the suface.The high-performance copper bonding wires can be bonded on the aluminum pad by thermo-sonic ball bonding in protection atomsphere and formatted excellent bonding and mechanical properties.The pads were not found damage after corroding. The number of CPK is 3.15 in the pull off test,the number of CPK is 2.5 in the shear stress test,both are excellent process capability index.The wire bending,each other up even,taking off the ball and the wire broken are not founded in the temperature cycling experiment..In the analysis of the spot morphology,found that the way of plastic deformation is slip.