Super Hydrophobic Polymeric Film for CMP Conditioner by Initiated Chemical Vapor Deposition (iCVD)

Chemical mechanical polishing (CMP) has been widely used in semiconductor manufacturing. The CMP process is essential for the planarization of semiconductor wafers and highly integrated devices, which is a process that mechanically removes the chemical reaction layer created on the wafer surface. At the same time, the slurry liquid is supplied onto the polishing pad with asperity. For this purpose, a slurry solution containing abrasive particles and chemical compounds to perform a polishing role, a polishing pad providing adequate pressure and asperity with the surface of a wafer, and a diamond conditioner for maintaining the surface roughness of the polishing pad are required.<br/>In the CMP process, shot asperity and glazing pores are produced due to friction and load applied between the CMP wafer and the CMP pad. In addition, the pores of the CMP pad are clogged by the slurry, thereby reducing the efficiency of the CMP process. In order to prevent this phenomenon, a diamond conditioner has been used to regenerate the pad surface and remove the slurry particles from the surface of the CMP Pad. The CMP pad conditioner has a stainless body with diamond edges fixed on Ni metal and an alloy coating. The diamond is shaken by physical force during the CMP process, which causes a crack. As acid or base solution penetrates this gap and corrodes the metal, diamonds fall out, or metal contamination occurs, damaging the wafer. The PTFE spray coating method has been applied to the CMP conditioner to prevent corrosive solutions such as acid and base. However, due to the poor bonding strength between PTFE and metal, the PTFE coating was easily peeled off from the load received during the CMP process, and it was not easy to coat uniformly.<br/>In this study, h hydrophobic polymer coating through ICVD method on the CMP conditioner and their hydrophobicity improvement were evaluated to prevent acid or base solution penetration. First, the surface of the CMP conditioner was modified using plasma and a silane coupling agent to increase the bonding force between the polymer coating and the metal. 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane was coated through the iCVD method, a technology that directly forms a polymer coating on the surface in the vapor phase. 1H,1H,2H,2H-Perfluorodecyl acrylate, which plays a role in hydrophobicity, was coated thereon. Characteristics of the surface of the CMP pad conditioner coated with the hydrophobic polymer were analyzed. FT-IR and XPS confirmed that organic materials were successfully formed on the surface, and the hydrophobicity of the surface was observed by the water droplet formed a high contact angle. In addition, the chemical stability of these CMP pad conditioners against corrosion from strong acid and the degree of peeling was tested in the CMP conditioning process.