Chemical Mechanical Polishing (CMP) Processes for Manufacturing Optical Silicon Substrates with Shortened Polishing Time

Silicon substrates are used in optical components for infrared systems and mirror systems. An alternative to processing of optical silicon substrates is chemical mechanical polishing (CMP). The conventional CMP uses a three-body abrasion. In this work, a two-body abrasion CMP, called the fixed abrasive CMP, is performed on silicon substrates. Experiments are performed and results show that the material removal rate (MRR) is largely dependent on head load. Similarly, an increase in table speed would give the same effect. Compared to the conventional CMP, MRRs for the fixed abrasive CMP process are much higher. This high processing efficiency would drastically reduce the time for polishing of silicon substrates. It has been confirmed that the total polishing time can be shortened to a few minutes from hours.