Abstract: A process for eliminating the effects of parasitic paths from stringers by forming diversionary paths in the overhangs in which the stringers are formed. The diversionary paths are selected such that the stringers formed in these paths are harmless to the operation of the circuit. For instance, in the formation of floating gate memory array where first and second polysilicon lines are formed are right angles to each other and then the first lines are etched in alignment with the second line to form the floating gates the invention is implemented by forming gaps in the first lines between the second lines. In this way, stringers formed from the second polysilicon layer are diverted. Consequently, the parasitic paths are paths in parallel with the second lines (word lines) instead of shorts between adjacent word lines.

Abstract: The present invention discloses a method for the etching of insulating films, specifically silicon oxide films, using a fluorine-helium-oxygen gas mixture in the fabrication of semiconductor devices. The method utilizes a prior art reactive ion etch system and adds a quantity of helium to a pre-established fluorine-oxygen chemistry to reactively etch the silicon oxide film while minimizing the occurrence of gate charging resulting from damage to the gate oxide. The addition of helium gas into the etch chemistry must be such that the flow of helium is at least 20% of the sum of the total fluorine, helium, and oxygen flows. The resulting etch chemistry, which can be used in any commercially available reactive ion etch system, produces a more uniform etch while reducing gate oxide damage so as to minimize charging of the semiconductor gate.