Solid state diffusion brazing of aluminum castings (AC4C) and wrought alloys (Al6061) was conducted in order to improve thermal conductivity and temperature uniformity of the aluminum heater which was generally fabricated by casting method. Tensile strength and thermal conductivity are raised with increasing brazing temperature, obtaining 122.5 MPa and $206W/m{cdot}K$ at $540^{circ}C$ 5hrs brazing conditions, respectively. The diffusion brazed heater, shows maximum temperature difference of $4^{circ}C$, exhibits a enhanced temperature uniformity compared with the cast heater having the maximum temperature difference of $11^{circ}C$.