Physical modeling of developable BARC at KrF

Resist CDU and profile control in high-resolution lithography are improved with the use of spin-on bottom anti-reflective coatings (BARCs). Typically, BARCs have not been applied on implant levels because they interfere with the doping process and also because of the cost of performing a reactive-ion etching step to open the BARC in bright areas. As implant CDs shrink to challenging k1 values, reflection control is increasingly required. One solution is to use a reactive-soluble antireflection layer to control CD and profile, thus eliminating the need for an additional etch step. Developable bottom antireflective coatings (DBARCs) provide improved control while minimizing increased cost. Computer simulation methods are a valuable tool for research and design. Complex reaction phenomena, often difficult to measure experimentally, may be studied within the limits of the models used, and their effect upon the resulting lithography evaluated. In this work, we describe DBARC functionality and application. The physics of a computer model for the study of DBARC is discussed. The effect of the model parameters upon the simulated lithography is discussed. The model is calibrated to experimental data and model predictions are compared to data of resist profiles on DBARC for key features at KrF.