There is disclosed a wafer processing apparatus having optimized electrode patterns for its resistive heating element. The optimized electrode pattern is designed to compensate for the heat loss around contact areas, electrical connections, and through-holes, etc., by generating more heat near or around those areas, providing maximum temperature uniformity. In another embodiment of the optimized design of the invention, the resistance of heating element closely matches the impedance of the power supply for higher efficiency, especially when higher operating temperature or higher electrical power is required.