Selective reactive ion etching of polysilicon against SiO2 utilizing SF6 -Cl2 -inert gas etchant

摘要: Disclosed is an improved Reactive Ion Etch (RIE) technique for etching polysilicon or single crystal silicon as must be done in Very Large Scale Integration (VLSI) using technology. It teaches the use of etch gas that consists a mixture sulfur hexafluoride (SF 6 ) and chlorine (Cl 2 diluted with inert gas. This allows RIE process which combines very desirable features selectivity (high Si/SiO rate ratio) directionality creates vertical side walls on etched features. Vertical mean no mask undercutting, hence zero bias. particularly applicable to device processing micron sub-micron sized lines fabricated extremely close tolerances. distinct improvement over wet chemical plasma it conventionally applied.