Boron or boron carbide based multilayers are widely used due to the boron-K absorption edge format λ=6.7nm. Pd/B<sub>4</sub>C has a relatively high theoretical reflectivity from 7.5nm to 11nm, compared to other candidates like Mo/B<sub>4</sub>C and La/B<sub>4</sub>C. It can also be easily fabricated by direct current magnetron sputtering technique. In this paper, different process parameters, including base pressure and sputtering pressure, are optimized to develop the Pd/B<sub>4</sub>C multilayer mirror. A reflectance of 36.2% were obtained at 9.41nm with 80 bilayers Pd/B<sub>4</sub>C. Reactive sputtering with nitrogen was also explored to improve the structure and reduce the stress of the Pd/B<sub>4</sub>C multilayers. The results showed that the EUV reflectance was not improved after the introduction of nitrogen while the stress was actually reduced.