The process of etching high aspect ratio SiB at high temperature

Silicon boron (SiB) often plays a role of hard mask material for HAR (high aspect ratio) dielectric etching process, which has the advantage of high selectivity. In this article, we mainly studied the process of etching high aspect ratio SiB at high temperature. With a mask, this process etch through SiB and stop in underneath dielectric film, we increased the evaporation of by-products during the etching process by raising the temperature, increased the etching rate, and utilized multi frequency pulse technology to provide high selectivity and improve the LCDU; At the same time, by adjusting the bias power and gas ratio, we solved the problem of polymer accumulation on the oxide top and SiB sidewall, and obtained an almost perfect etching profile.