Development of new tight-binding molecular dynamics program to simulate chemical-mechanical polishing processes

We developed a new accelerated quantum chemical molecular dynamics program called "Colors" which can simulate the chemical-mechanical polishing (CMP) processes. It is more than 5,000 times faster than the regular first-principles molecular dynamics program, since it is based on our original tight-binding theory. We employed a SiO₂ particle as a polishing material. Two types of silicon surfaces, clean Si(100) and H-terminated Si(100) 2 × 1, were modeled to clarify the effect of the Si surface structure on the dynamic behaviors of the CMP processes. We paid attention to the bond population of the silicon atom during the CMP processes. The bond population of the silicon atom was decreased by the CMP process on both surfaces, indicating that the electronic state of the silicon wafer became unstable due to the CMP process. It is an interesting finding that the hydrogen atoms were desorbed from the H-terminated Si(100) 2 × 1 surface. The results indicate that our new program can simulate both the chemical reactions and mechanical polishing processes. To the best of our knowledge, this is the first simulator of the CMP processes on the atomic and electronic levels.