Unidirectional Growth of Microbumps on (111)-Oriented and Nanotwinned Copper

Tiny Tinny Bumps One challenge in moving to three-dimensional integrated circuit architectures is the need for aligned interconnects to join neighboring layers. Hsiao et al. (p. 1007 ) applied rapid stirring to the direct current electroplating of copper to produce films with oriented copper grains that have a high density of nanotwin defects. The resulting material was an excellent platform for the growth of copper-tin intermetallic compounds in the form of arrays of microbumps potentially suitable for the soldering of electronic components.