Schematic of the flip chip test structure used in this experiment. (a) The carrier and (b) the die designs. Au metal is used as the metallization material and Ni as the catalyst for the CNT growth. At the sides of each structure, two rows of square patches are also patterned and deposited with the Ni catalyst on Au for CNT growth. These additional CNT bumps serve as dummy bumps to increase bump densities for mechanical supports.