The invention relates to a gold coated
copper bonding wire and a preparation method thereof. The gold coated
copper bonding wire is formed by combining core wire
copper and a gold
coating layer, the
diameter of the bonding wire is 10-50 mum, and the ratio of the area of the gold
coating layer to that of the cross section is 10-30%. The preparation method comprises the following steps: adopting an
oxygen-free copper rod with the
diameter of 5-30 mm as the core material, and adopting the reversed solidification method to prepare a gold coated copper composite wire blank; carrying out multi-pass hole pattern rolling and / or drawing
processing on the composite wire blank to obtain a
wire rod with the
diameter of 3-8 mm, wherein the
rolling speed is 10-200 m / min, and the
reduction rate of the single-pass section is 10-50%, or the drawing speed is 5-50 m / min, and the
reduction rate of the single-pass section is 10-30%; then, carrying out rough drawing
processing and fine drawing
processing on the composite
wire rod formed by rolling processing and / or drawing processing to prepare the gold coated copper bonding wire; middle annealing can be exerted in the drawing process, the annealing temperature is 100-400 DEG C, and the annealing time is 10-60 min. The gold coated copper bonding wire is compact in
coating layer, uniform in thickness, high in
bonding strength of the interface, excellent in processability, low in possibility of web breaking and wire breaking, short in preparation technological process, high in yield and low in manufacturing cost.