Apparatus for the etching for semiconductor devices

Claim 1

Apparatus for etching semiconductor devices comprising, in combination: an etching chamber adapted to contain the semiconductor device to be etched; an electrodeless etching plasma forming chamber having an inlet connected to a source of continuously flowable etching gas and having an outlet connected to said etching chamber in fluid flow communication; a helical inductive resonator coupler for coupling a source of R.F. electrical power into said electrodeless plasma forming chamber for continuously forming etching plasma from the etching gas flowing therethrough, said helical inductive resonator coupler comprising: a grounded hollow cylinder of electrically conductive material with a grounded base member at one end thereof; a helically coiled wire conductor concentrically mounted within the cylinder and spaced from the inner walls thereof; means for mounting said plasma forming chamber substantially concentrically within the coil; the end of the coil toward said base member being grounded, and electrical coupling means for applying to the coil a source of R.F. electrical power that is sufficient to maintain a discharge in said plasma forming chamber mounted within the coil, said coupling means applying power into the coil at a position near, but spaced from, the grounded end thereof, said position being selected such that, when said plasma forming chamber is in operation by the R.F. power being applied to the coil, the impedance of said plasma forming chamber and coupling means at said position substantially matches the impedance of said R.F. power source, whereby when said R.F. power is applied to the coil, and before a discharge is ignited in said plasma forming chamber, a voltage maximum occurs at the end of the coil remote from said grounded end and creates a potential extending through the portion of said plasma chamber between said end remote from the grounded end and said base member for ionizing the gas in said plasma forming chamber.