Cyanide-free sulfite-based gold electroplating for microbump fabrication in packaging
[Introduction] Under the strategy of sustainable industrial development, the environmentally friendly cyanide-free gold electroplating technology is gradually replacing the traditional cyanide-based gold electroplating technology, and has been widely applied in the field of microelectronic packaging. [Method] A novel cyanide-free sulfite-based bath composition for gold electroplating was developed in respect of the gold microbumping process in liquid crystal display (LCD) driver chip packaging. [Result] Organic phosphonic acid and crystal adjusting agent were added to the self-developed cyanide-free electroplating solution. The former could efficiently inhibit nickel-gold replacement, while the latter helped to form equiaxial crystals with low stress, avoiding extrusion and deformation of photoresist during gold electroplating. Gold microbumps with smooth and uniform microscopic surface and free of defects could be obtained on wafer by the given cyanide-free gold electroplating process. [Conclusion] The cyanide-free gold electroplating process can meet the requirements of wafer-level packaging, showing great potential in industrial applications.
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维普
