Method for preparing single-crystal copper bonding wire

Abstract

The invention relates to a method for preparing a single-crystal copper bonding wire, which uses copper as a raw material. The method comprises the following steps: melting high purity copper of which the purity is higher than 99.995 percent by using a high-vacuum furnace, raising the temperature to between 1,100 and 1,180 DEG C, refining the copper for 60 to 120 minutes, and adopting high purity argon for protection in the whole melting process; broaching single-crystal copper rods of phi 4 to phi 8 mm in a directional solidification mode, and then coldworking the single-crystal copper rods to between phi 0.95 and phi 1.102 mm with the broaching working rate of 15 to 25 percent for each gate; broaching the single-crystal copper rods to between 0.020 and 0.05 mm with 47 to 70 gates and the working rate of 7.59 to 17.82 percent for each gate; and carrying out sonicleaning on the surface of the single-crystal copper bonding wire when the wiredrawing temperature is between 35 and 45 DEG C, carrying out heat treatment on the cleaned single-crystal copper bonding wire, and using H2+Ar2 for protection with the temperature of between 410 and 425 DEG C, the time of between 0.7 and 2.0s and the annealing rewinding tension of between 0.6 and 2.8g.

Description

technical field [0001] The invention relates to the processing and preparation of single crystal copper materials. Background technique [0002] Wire bonding is dominant in chip connection due to its simple process, low cost, and suitability for a variety of packaging forms. At present, more than 90% of all package pins are connected by wire bonding. Compared with gold wire and aluminum wire, copper bonding wire has excellent mechanical properties, electrical properties, thermal properties and low growth of intermetallic compounds, which greatly improves chip frequency and reliability, and adapts to low cost, thin The development of spacing and high-terminal component packaging. In addition, the transition from wafer aluminum metallization to copper metallization makes for new package designs of high-speed devices, the choice of short copper wire bonding and copper pads with a pitch of less than 50 μm will become a powerful flip-chip process in the packaging market. compet...

AI Technical Summary

Problems solved by technology

However, for the oxygen-free copper rod of the copper bonding wire, due to the large number of grain boundaries in its internal structure, when drawing ultra-fine wires, fractures will occur at the grain boundaries, and it must be processed to less than 0.03mm to ensure good There will be more difficulties in performance consistency