Variable Volume Plasma Processing Chamber and Associated Methods

Abstract

A plasma processing chamber includes a substrate support having a top surface defined to support a substrate in a substantially horizontal orientation within the chamber. The plasma processing chamber also includes a number of telescopic members disposed within the chamber outside a periphery of the substrate support. The number of telescopic members are also disposed in a concentric manner with regard to a center of the top surface of the substrate support. Each of the number of telescopic members is defined to be independently moved in a substantially vertical direction so as to enable adjustment of an open volume above the top surface of the substrate support, and thereby enable adjustment of a plasma condition within the open volume above the top surface of the substrate support.

1 . A plasma processing system, comprising:
 a chamber defined to include,
 a substrate support having a top surface defined to support a substrate in a substantially horizontal orientation within the chamber, 
 a plurality of telescopic members disposed within the chamber outside a periphery of the substrate support and concentric with both a center of the top surface of the substrate support and with each other, wherein each of the plurality of telescopic members is defined to be independently moved in a substantially vertical direction relative to the top surface of the substrate support so as to enable modification of an open volume above the top surface of the substrate support; 
   metrology defined to monitor a condition of a plasma to be generated within the open volume and generate signals indicative of the plasma condition; and   a control system defined to direct movement of one or more of the plurality of telescopic members in accordance with the signals to be generated by the metrology so as to maintain a target plasma condition within the open volume.   
     
     
         2 . A plasma processing system as recited in  claim 1 , wherein the plurality of telescopic members are defined as concentric cylinders. 
     
     
         3 . A plasma processing system as recited in  claim 1 , wherein the substrate support is defined as a radiofrequency powered electrode. 
     
     
         4 . A plasma processing system as recited in  claim 3 , wherein each of the plurality of telescopic members is formed from a metal and is electrically connected to a ground potential such that movement of one or more of the plurality of telescopic members relative to the substrate support influences a radiofrequency power return path. 
     
     
         5 . A plasma processing system as recited in  claim 1 , wherein the plurality of telescopic members are defined to move sequentially so as to avoid formation of a plasma pocket outside either of the plurality of telescopic members. 
     
     
         6 . A plasma processing system as recited in  claim 1 , wherein each of the plurality of telescopic members is defined radially adjacent to its neighboring ones of the plurality of telescopic members such that a radial gap is not present between any neighboring ones of the plurality of telescopic members. 
     
     
         7 . A plasma processing system as recited in  claim 1 , wherein each of the plurality of telescopic members is structurally defined such that the plurality of telescopic members form a contiguous telescopic member arrangement at all vertical positions of the plurality of telescopic members. 
     
     
         8 . A plasma processing system as recited in  claim 1 , wherein the plurality of telescopic members is three telescopic members. 
     
     
         9 . A plasma processing system as recited in  claim 1 , wherein each of the plurality of telescopic members is defined to have a different radial thickness such that the radial thickness of the plurality of telescopic members increases with increased radial position relative to the substrate support. 
     
     
         10 . A plasma processing system as recited in  claim 1 , wherein a telescopic member having a radial position closest to the substrate support includes an inner surface profile defined to optimize a radiofrequency power coupling uniformity and gas flow dynamics within the chamber. 
     
     
         11 . A plasma processing system as recited in  claim 1 , wherein each of the plurality of telescopic members is formed from a dielectric material. 
     
     
         12 . A plasma processing system as recited in  claim 1 , wherein at least one of the plurality of telescopic members is fowled from a dielectric material and at least one of the plurality of telescopic members is formed from an electrically conductive material connected to a ground potential. 
     
     
         13 . A plasma processing system as recited in  claim 1 , wherein a home position of the plurality of telescopic members is defined within an upper region of the chamber, each of the plurality of telescopic members defined to be independently moved downward from the home position so as to enable adjustment of the open volume above the top surface of the substrate support. 
     
     
         14 . A plasma processing system as recited in  claim 1 , wherein a home position of the plurality of telescopic members is defined within a region of the chamber below the top surface of the substrate support, each of the plurality of telescopic members is defined to be independently moved upward from the home position so as to enable adjustment of the open volume above the top surface of the substrate support. 
     
     
         15 . A plasma processing system as recited in  claim 1 , further comprising:
 a motor mechanically connected to move each of the plurality of telescopic members.   
     
     
         16 . A plasma processing system as recited in  claim 15 , wherein the motor is a stepper motor. 
     
     
         17 . A plasma processing system as recited in  claim 15 , wherein the motor is defined to limit movement of each of the plurality of telescopic members from a respective home position to a position of its immediately surrounding telescopic member. 
     
     
         18 . A plasma processing system as recited in  claim 1 , further comprising:
 a temperature control system defined to monitor and control a temperature of one or more of the plurality of telescopic members.   
     
     
         19 . A plasma processing system as recited in  claim 1 , wherein one or more of the plurality if telescopic members is defined to have a magnet embedded therein. 
     
     
         20 . A plasma processing system as recited in  claim 1 , wherein the metrology is further defined to detect a response on a surface of the substrate by detecting one or more of a change in optical emission spectrum of the plasma when generated within the open volume, a change in bias voltage at the substrate, and a change in impedance of a radiofrequency (RF) circuit formed through the chamber.