Plasma processing apparatus with reduced effects of process chamber asymmetry

Abstract

Plasma processing apparatus that provide an asymmetric plasma distribution within the processing apparatus are provided herein. In some embodiments, a plasma processing apparatus may include a process chamber having a processing volume with a substrate support disposed therein; and a first RF coil disposed above the substrate support to couple RF energy into the processing volume, wherein an electric field generated by RF energy moving along the first RF coil is asymmetric about a central axis of the substrate support. In some embodiments, a pump port is disposed asymmetrically with respect to the processing volume to remove one or more gases from the processing volume. In some embodiments, the first RF coil is asymmetrically disposed about the central axis of the substrate support.

1 . A plasma processing apparatus, comprising:
 a process chamber having a processing volume with a substrate support disposed therein; and   a first RF coil disposed above the substrate support to couple RF energy into the processing volume, wherein an electric field generated by RF energy moving along the first RF coil is asymmetric about a central axis of the substrate support.   
     
     
         2 . The plasma processing apparatus of  claim 1 , comprising:
 a pump port to remove one or more gases from the processing volume, wherein the pump port is disposed asymmetrically with respect to the processing volume.   
     
     
         3 . The plasma processing apparatus of  claim 2 , wherein the first RF coil is configured such that the electric field produced during use is weaker above a first portion of the processing volume proximate the pump port than above a second portion of the processing volume opposing the pump port. 
     
     
         4 . The plasma processing apparatus of  claim 2 , wherein the electric field is weaker above a first portion of the processing volume proximate the pump port than above a third portion of the processing volume adjacent to the first portion of the processing volume. 
     
     
         5 . The plasma processing apparatus of  claim 2 , wherein the first RF coil is asymmetrically disposed about the central axis of the substrate support. 
     
     
         6 . The plasma processing apparatus of  claim 2 , wherein the first RF coil further comprises:
 at least one conductor winding about the central axis of the substrate support and toward a periphery of the processing volume from a first end disposed proximate the central axis of the substrate support to a second end.   
     
     
         7 . The plasma processing apparatus of  claim 6 , wherein an outermost winding of the at least one conductor is disposed internally from the periphery of the processing volume. 
     
     
         8 . The plasma processing apparatus of  claim 7 , wherein the at least one conductor further comprises:
 a first winding; and   a second winding adjacent to the first winding, wherein a distance between the first winding and the second winding varies.   
     
     
         9 . The plasma processing apparatus of  claim 8 , wherein the distance is largest above a first portion of the processing volume proximate the pump port. 
     
     
         10 . The plasma processing apparatus of  claim 2 , wherein the first RF coil further comprises:
 a plurality of conductors winding about the central axis of the substrate support and toward a periphery of the processing volume from respective first ends of the plurality of conductors disposed proximate the central axis of the substrate support to respective second ends of the plurality of conductors.   
     
     
         11 . The plasma processing apparatus of  claim 10 , wherein at least one of the plurality of conductors is disposed asymmetrically about the central axis of the substrate support. 
     
     
         12 . The plasma processing apparatus of  claim 10 , wherein each of ones of the plurality of conductors are disposed asymmetrically about the central axis of the substrate support and wherein each of ones of the plurality of conductors are disposed symmetrically with respect to each other. 
     
     
         13 . The plasma processing apparatus of  claim 12 , wherein a distance between any two adjacent conductors is constant along respective lengths of the adjacent conductors. 
     
     
         14 . The plasma processing apparatus of  claim 1 , further comprising:
 a second RF coil disposed above the substrate support to couple RF energy into the processing volume.   
     
     
         15 . The plasma processing apparatus of  claim 14 , wherein the first RF coil is an outer coil and the second RF coil is an inner coil symmetrically disposed about the central axis of the substrate support. 
     
     
         16 . The plasma processing apparatus of  claim 15 , wherein the second RF coil further comprises:
 at least one conductor winding about the central axis of the substrate support and toward a periphery of the processing volume from a first end disposed proximate the central axis of the substrate support to a second end.   
     
     
         17 . The plasma processing apparatus of  claim 1 , wherein the process chamber further comprises:
 a dome disposed above the substrate support, wherein the first RF coil is disposed about the dome external to the processing volume.   
     
     
         18 . A plasma processing apparatus, comprising:
 a process chamber having a processing volume with a substrate support disposed therein and a ceiling disposed above the substrate support;   an outer RF coil disposed proximate the ceiling external to the processing volume to couple RF energy into the processing volume, wherein the outer RF coil includes at least one first conductor asymmetrically disposed about the central axis of the substrate support;   an inner RF coil about the ceiling external to the processing volume to couple RF energy into the processing volume, wherein the inner RF coil includes a second conductor symmetrically disposed about the central axis of the substrate support; and   a pump port disposed asymmetrically with respect to the processing volume, wherein the electric field is weaker above a first portion of the processing volume proximate the pump port than above a second portion of the processing volume opposing the pump port.   
     
     
         19 . The plasma processing apparatus of  claim 18 , wherein the outer RF coil further comprises:
 a plurality of conductors winding about the central axis of the substrate support and toward a periphery of the processing volume from respective first ends of the plurality of conductors disposed proximate the central axis of the substrate support to respective second ends of the plurality of conductors, and wherein an outermost winding of the plurality of conductors is disposed internally from the periphery of the processing volume.   
     
     
         20 . A plasma processing apparatus, comprising:
 a process chamber having a processing volume with a substrate support disposed therein;   a pump port disposed asymmetrically with respect to the processing volume; and   a plasma generator comprising:
 an signal generator; and 
 an electrode coupled to the signal generator to create an electric field within the processing volume upon application of energy from the signal generator, wherein the electric field has an asymmetric geometry relative to a central axis of the substrate support.