New Silver Alloy Bonding Wire Based on Environmentally Friendly Cathodic Passivation Protection and Its reliability

摘要

As one of the four key basic materials in the field of microelectronic packaging, Bonding wire is the internal lead to realize the electrical interconnection between chip and lead frame. Its quality directly determines the performance of microelectronic packaging products. As a non-traditional bonding wire, silver alloy wire has excellent conductivity, ductility, high reflectivity and excellent performance. It is the main direction to replace traditional bonding wire in the future. However, the bonded wire with high silver content is prone to silver ion migration under wet conditions, and is prone to surface discoloration caused by sulfide and oxygen corrosion in the air, which affects the reflectivity, long-term reliability and service life of the silver wire. In this paper, EDS, tensile tester, Color difference spectrometer were used to analyze the anti-corrosion ability and wire pull of 98.5% Ag / 1.5% Pd alloy silver bonding wire before and after treatment, and spectroradiometer was used to compare the reflectance of silver alloy wire in the air after one month of corrosion before and after treatment. Finally, after 85 °C /85%RH constant temperature / humidity experiment, test its conductivity and luminous flux. The results showed that the wire pull of the silver alloy wire before and after treatment was 9.60gf and 9.30gf, and after 85 ° C / 85% RH experiments, the difference in conductivity between the silver alloy wires before and after treatment was only 0.27%, and the difference in light attenuation was 0.72%. Finally, based on the new environmental protection passivation process of trivalent chromium cathode, a kind of smooth and compact silver based bonding wire coated with nano biofilm can be obtained, and its standards are in line with the national standards.