Since the 80's, the utilization of hybrid integrated circuits to automobiles have been increasing. There is a well-known trend that the diameter of flipchip bumps are becoming smaller and smaller but with more number of flipchip bumps in a circuit. ln this paper,the development of the fabrication of through holes by the bump photo process to produce small flipchip bumps using thick resist is reported. SN ratio was used for the analysis to maximize the uniformity of hole dimentions.