This paper deals with the planarization of copper bumps to improve the bonding performance and reliability of printed circuit board (PCB) manufacturing to improve by using flip chip during the fabrication process of the PCB. Authors tried to develop a novel planarization process using polishing techniques before the continuous process at the PCB fabrication. An experiment was implemented by mechanical polishing (MP) using alumina abrasives mixed with deionizer water (DIW), and by chemical mechanical polishing (CMP) added with oxidizer of HF. CMP showed superior results to MP with mirror surface less than Ra 3nm and minimum step height deviation of 1um, resulting in high bonding performance and reliability. Therefore, CMP is a strong tool for reserving a sufficient margin in the PCB manufacture process.