OPC of resist reflow process

One of the most critical issues for sub-100 nm patterning is patterning a fine contact hole. The resist reflow process is a good method due to its simplicity without the additional complex process steps and due to its efficient technique with the appropriate selection of the resist properties and the thermal loading process conditions. However, it is difficult to use this process to the production process because the optical proximity effect of thermal reflow is quite severe. In this study, the optical proximity effects before and after thermal reflow are described. Resist reflow process is modeled and simulated for a top-view image. For repeating contacts, thermal reflow bias is modeled and is compensated according to the form of contact type. Simulated results agree well with the experimental results in a small error range according to the baking temperature, time, and pitch size. The model-based OPC before thermal reflow is performed for 65 nm contact hole by using the simulated images, so that the possibility of thermal reflow for the formation of a sub-100 nm pattern is shown.