CONTROLLED ELECTROPLATED SOLDER BUMPS

The uniformity of the composition of plated solder bumps from one batch of wafers to another is improved by controlling the rotational speed of the wafers based on the particular solder bump pattern. Embodiments include sequentially horizontal fountain electroplating a pattern of solder bumps, e.g., SnAg solder bumps, on a plurality batches of wafers and controlling the rotational speed of each batch of wafers during electroplating based on a calibration plot of the concentration of a solder bump component, e.g., Ag, as a function of rotational speed for each solder bump pattern, such that the uniformity of the Ag concentration in the patterns of solder bumps is greater than 95%, e.g., greater than 98%. Embodiments further include electroplating in the same plater sequential batches of wafers having both different patterns and different solder bump compositions at the same high throughput.