Abstract: In a process for etching by reactive ion etching, a ceramic partially masked by an organic photoresist, an etch gas containing SF.sub.6, a noble gas and a small percentage of a carbon-containing gas is used.

Abstract: Disclosed is an improved Reactive Ion Etching (RIE) technique for etching polycrystalline silicon or single crystal silicon as must be done in Very Large Scale Integration (VLSI) using silicon technology. It teaches the use of an etch gas that consists of a mixture of silicon tetrafluoride (SiF.sub.4) and chlorine (Cl.sub.2) diluted with inert gas. This etch gas allows an RIE process which combines the very desirable features of selectivity (high Si/SiO.sub.2 etch rate ratio), directionality which creates vertical sidewalls on the etched features and contains no contaminants which can cause yield problems in VLSI circuits. Vertical side walls means no mask undercutting, hence zero etch bias.

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

Abstract: An improved Reactive Ion Etching (RIE) technique for preferentially etching polysilicon is described as is needed in Very Large Scale Integration (VLSI) using silicon technology. The etch gas is a mixture of carbon tetrafluoride (CF.sub.4) and chlorine (Cl.sub.2) diluted with inert gas. The pressure of the system is required to be in the range of about 10 to 500 milli Torr. This etch gas allows an RIE process which combines the very desirable features of selectivity (high polycrystalline silicon/monocrystalline silicon etch rate ratio) and directionality which creates substantially vertical sidewalls on the etched features.