Etching apparatus and method

Abstract

A method includes forming an inner chamber in a process chamber of a plasma processing apparatus, the inner chamber having smaller volume than the process chamber. At least one gas is introduced into the inner chamber, and flow of the at least one gas into the inner chamber is measured. The flow of the at least one gas is adjusted to a desired rate, and a wafer is processed by the at least one gas at the desired rate while the inner chamber is not formed.

What is claimed is: 
     
         1 . An apparatus, comprising:
 a process chamber;   an electrostatic chuck in the process chamber;   a sealing ring in the process chamber and laterally surrounding the electrostatic chuck; and   a chamber confinement assembly configured to shift position of the sealing ring vertically to a first position to establish an inner chamber in the process chamber during a flow verification process, and to shift position of the sealing ring to a second position to flow gas into the process chamber during processing of a wafer.   
     
     
         2 . The apparatus of  claim 1 , further comprising:
 a flow verification unit configured to measure flow of the gas into the inner chamber during the flow verification process.   
     
     
         3 . The apparatus of  claim 1 , wherein a ratio of volume of the inner chamber to volume of the process chamber is in a range of about 0.1 to about 0.5. 
     
     
         4 . The apparatus of  claim 1 , wherein the chamber confinement assembly is further configured to shift position of an upper portion of the process chamber vertically toward the sealing ring when establishing the inner chamber. 
     
     
         5 . The apparatus of  claim 1 , further comprising an upper electrode configured to supply radio frequency power to generate a plasma in the process chamber. 
     
     
         6 . The apparatus of  claim 5 , wherein the chamber confinement assembly is further configured to shift the position of the sealing ring vertically to contact the upper electrode. 
     
     
         7 . The apparatus of  claim 5 , further comprising a spectral and/or charge monitoring system configured to measure characteristics of the plasma in the inner chamber. 
     
     
         8 . An apparatus, comprising:
 a process chamber;   an electrostatic chuck in the process chamber;   a sealing ring in the process chamber and laterally surrounding the electrostatic chuck;   a chamber confinement assembly configured to form an inner chamber in the process chamber during a flow verification process, and to remove the inner chamber during processing of a wafer, the inner chamber having smaller volume than the process chamber; and   a gas source configured to:
 introduce at least one gas into the inner chamber; and 
 introduce the at least one gas at a selected rate while the inner chamber is not formed. 
   
     
     
         9 . The apparatus of  claim 8 , further comprising a flow verification unit configured to measure flow of the gas into the inner chamber during the flow verification process. 
     
     
         10 . The apparatus of  claim 8 , wherein the inner chamber has about 10% to about 50% smaller volume than the process chamber. 
     
     
         11 . The apparatus of  claim 8 , wherein the chamber confinement assembly is further configured to:
 shift position of the sealing ring vertically toward an upper portion of the process chamber.   
     
     
         12 . The apparatus of  claim 11 , wherein when the chamber confinement assembly shifts the position, the chamber confinement assembly shifts the position of the sealing ring vertically until the sealing ring contacts at least an upper electrode of the upper portion. 
     
     
         13 . The apparatus of  claim 8 , further comprising an upper electrode configured to supply radio frequency power to generate a plasma in the process chamber. 
     
     
         14 . The apparatus of  claim 13 , further comprising a spectral and/or charge monitoring system configured to measure characteristics of the plasma in the inner chamber. 
     
     
         15 . An apparatus, comprising:
 a process chamber;   an electrostatic chuck in the process chamber;   a sealing ring in the process chamber and laterally surrounding the electrostatic chuck;   a chamber confinement assembly including:
 an upper actuator configured to shift an upper portion of the process chamber vertically downward from a first position to a second position; and 
 a lower actuator configured to shift the sealing ring vertically upward from a third position to a fourth position; and 
   a gas source configured to:
 while the upper portion is in the second position and the sealing ring is in the fourth position, introduce at least one gas into an inner chamber formed between the upper portion and the sealing ring; and 
 while the upper portion is in the first position and the sealing ring is in the third position, introduce the at least one gas at a selected flow rate into the process chamber to process a wafer. 
   
     
     
         16 . The apparatus of  claim 15 , wherein the chamber confinement assembly comprises:
 a horizontal base portion in contact with the lower actuator; and   a vertical extension in contact with the horizontal base portion and the sealing ring.   
     
     
         17 . The apparatus of  claim 16 , wherein the lower actuator comprises a ball screw configured to be extended by a servo motor. 
     
     
         18 . The apparatus of  claim 15 , further comprising:
 an optical emission spectrometer configured to measure characteristics of a plasma in the inner chamber;   wherein the sealing ring includes at least a portion aligned with the optical emission spectrometer, the portion being substantially transparent.   
     
     
         19 . The apparatus of  claim 15 , wherein inner diameter of the sealing ring is greater than diameter of an electrostatic chuck by less than about 0.1 millimeters. 
     
     
         20 . The apparatus of  claim 15 , wherein while the upper portion is in the second position and the sealing ring is in the fourth position, the apparatus is configured to:
 measure at least two temperatures of the inner chamber corresponding to at least two pressures; and   determine the flow rate based on the at least two pressures and the at least two temperatures.