PROCEDE POUR LA GRAVURE NON PREFERENTIELLE DU SILICIUM PAR UN MELANGE GAZEUX, ET MELANGE GAZEUX POUR CETTE GRAVURE

1305625 Etching MOTOROLA Inc 9 Sept 1970 [29 Sept 1969] 43184/70 Heading B6J In a method for non-preferential etching of silicon, e.g. for preparing semi-conductor material, the silicon is contacted by a gaseous mixture containing sulphur hexafluoride having below 1300 p.p.m. by weight of nitrogen impurity, and a gas taken from the group hydrogen, helium or argon, whilst maintaining the temperature of said silicon between 950‹ and 1250‹ C. A silicon wafer may be heated on a quartz slab, resting on a graphite susceptor, by radio-frequency induction, the supply of sulphur hexafluoride in the gas mixture being cut off when sufficient etching has taken place. Other etchants such as ClF 3 , HCl, HF and H 2 S may be added to the mixture.