Abstract: The microstructure and properties of successive cold processed single-crystal copper bonding wire are investigated. The effects of annealing temperature and annealing time on the break load, elongation and resistivity of single-crystal copper bonding wire are analyzed. It is found that the microstructure of as-drawing single-crystal copper bonding wire is fibrous texture and the break load and resistivity increase distinctly whereas elongation is decreased contrarily. The break load and resistivity have the same decrease trend with the increase of annealing time and annealing temperature but the elongation increase contrarily. The result shows that the optimum break load and elongation are obtained at 420 ℃ and 2.4 s annealing process especially for 0.025 mm single crystal copper bonding wire and the surface quality strongly depends on the annealing process and outer circumstance. The single crystal copper bonding wire’s diameter has relationship with the annealing temperature and annealing time which accord with the quadratic function.

Key words: Breaking load, Electrical resistivity, Elongation rate, Fitting, Single-crystal copper bonding wire