A new method for building solder bumps for advanced packaging

Summary form only given. The two basic approaches that are currently being used to build solder bumps-wet electroplating and dry evaporation-are subject to strong limitations that prevent a wider application throughout the electronics industry. These limitations are nonuniformities and impurities for the electroplating process, and large investments for process development and production implementation for the evaporation-through-metal-mask process. At MCNC, a method of building small-size (d approximately 1 mil) solder bumps is being developed. The process utilizes conventional thin-film equipment and processes, and soldering equipment and processes. High-yield solder-bumped wafers and/or substrates can be obtained. The process outline and results are presented.<>