A printed circuit board (PCB) is equipped with electronic devices. PCB is a laminate composite made of copper and resin. Electronic circuit in PCB is made of copper. PCB is heated in a furnace in order to fix electronic devices. This process is called a reflow process. PCB deforms in a reflow process by thermal extension difference between copper and resin. An analytical model was proposed to calculate deformation of PCB. Laminate mechanical model and micro mechanical model were used in the

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... ling. Area of copper circuit pattern was optimally decided in order to minimize PCB deformation. The analytical model and the method of feasible direction were used in the optimization. Upper and lower limits of copper area decided by circuit design were taken into consideration in the optimization.