Radial flow reactor including glow discharge limitting shield

Abstract

An improved radio frequency (rf) powered radial flow cylindrical reactor utilizes a gas shield which substantially limits the glow plasma discharge reaction to a section of the reactor over the semiconductor substrates which are to be coated. The gas shield permits the use of higher rf input power which contributes to the formation of protective films that have desirable physical and electrical characteristics.

What is claimed is: 
     
       1. .[.Coating apparatus.]. .Iadd.Apparatus .Iaddend.comprising: an evacuable chamber;   a member located in said chamber having a support region adapted to support at least one object and a central region which defines an aperture therethrough;   means for facilitating a radio frequency discharge within the chamber adjacent the object to form a .[.flow.]. .Iadd.glow .Iaddend.discharge plasma from reactant gases introduced into the chamber;   exhaust means in communication with the centrally disposed aperture in the member; and   .[.coating.]. gas-vapor feed means located adjacent the support region of the member such as that gas-vapor feed is induced to flow across the support region of the member in a radial flow and out through the exhaust means, the .[.coating.]. gas-vapor feed means being adapted to substantially inhibit any glow plasma discharge reaction from occurring until reactant gases introduced into .[.he.]. .Iadd.the .Iaddend.apparatus through the .[.coating.]. gas-vapor .Iadd.feed .Iaddend.means reach the support region of the member.   
     
     
       2. Apparatus for coating a substrate comprising: an evacuable chamber;   a member located in said chamber having a top region which is adapted to hold the substrate and a central region defining an aperture therethrough;   means for generating a radio frequency discharge within the chamber adjacent the substrate to form a glow discharge plasma from reactant gases introduced into said chamber;   means for establishing a radial flow from an outer portion of the member which is adapted to hold the substrate toward and out of the aperture of the reactant gases suitable for forming the plasma and coating on the substrate;   means in communication with the aperture for exhausting the gases; and   means for substantially confining said plasma glow discharge to a zone which encompasses the top region of the member and extends substantially vertically upward therefrom.   
     
     
       3. The apparatus of claim 2 further comprising heating means contained within the chamber for heating the substrate to a preselected temperature. 
     
     
       4. The apparatus of claim 2 wherein the means for generating a glow discharge includes substantially parallel electrodes within the chamber. 
     
     
       5. The apparatus of claim 4 wherein the chamber is electrically coupled to one of the electrodes. .Iadd. 6. Apparatus comprising: an evacuable chamber having an input port and an output port;   a member located in said chamber having a support region adapted to support at least an object;   means for facilitating a radio frequency discharge within the chamber adjacent the support region of the member located therein; and   gas feed means in communication with the input port which includes shielding means disposed so as to substantially confine the radio frequency discharge to a portion of the chamber adjacent to the support region of the member. .Iaddend..Iadd. 7. A radial flow reactor comprising a chamber adapted to be evacuated, there being disposed within said chamber:   a first electrode;   a second electrode including a supporting region in spaced relation with said first electrode and adapted, in cooperation with said first electrode, to create a plasma discharge between said electrodes; and   gas feed means for flowing a gas suitable for use in a plasma discharge reaction process in radial directions across the supporting region of said second electrode; and   CHARACTERIZED IN THAT   the gas feed means includes shielding means disposed around portions of the second electrode for substantially confining the plasma flow discharge at the second electrode to the supporting region thereof. .Iaddend..Iadd. 8. A reactor as in claim 7 wherein said gas is introduced into said chamber adjacent to the side of said second electrode opposite to the side thereof facing said first electrode, said second electrode having an aperture through a central portion of said supporting region, and including exhausting means connected to said aperture and being effective for exhausting the space immediately surrounding said supporting region; and   CHARACTERIZED IN THAT   said shielding means defines a path for the flow of gas from where it is introduced into said chamber to immediately adjacent said supporting region, said shielding means shielding said path from said first electrode for preventing a plasma glow discharge along said path. .Iaddend..Iadd. 9. A reactor as in claim 8 further CHARACTERIZED BY heating elements included within the second electrode. .Iaddend.