Influence of metallographic preparation on electron backscatter diffraction characterization of copper wire bonds

The advantages of copper wire bonding compared to gold wire bonding, such as lower material costs, have led to an increased interest in reliability of copper bonds. The knowledge of the bonded wire microstructure is essential to achieve high-reliability bonding. This study focuses on the metallographic preparation of a bonded cross-sectioned sample for achieving a high-quality planar surface, suitable for electron backscattered diffraction (EBSD) technique. This technique was used for crystal orientation mapping of a thermosonic (ball) bonded copper wire. Because of the sensitivity of EBSD technique to surface defects and preparation artifacts, it was used for the evaluation of preparation quality.