Plasma etching apparatus and plasma etching method

Abstract

The invention provides a method and apparatus for performing plasma etching to form a gate electrode on a large-scale substrate while ensuring the in-plane uniformity of the CD shift of the gate electrode. The present invention measures a radical density distribution of plasma in the processing chamber, feeds processing gases into the processing chamber through multiple locations and controls either the flow rates or compositions of the respective processing gases or the in-plane temperature distribution of a stage on which the substrate is placed, or feeds processing gases into the processing chamber through multiple locations and controls both the flow rates or compositions of the processing gases and the in-plane temperature distribution of the stage on which the substrate is placed.

1 . A plasma etching apparatus comprising:
 a vacuum processing chamber for subjecting a substrate to plasma processing:   a substrate stage disposed in the vacuum processing chamber having a support surface for supporting the substrate;   a gas inlet for supplying processing gas into the vacuum processing chamber;   an electromagnetic wave supply means for supplying electromagnetic waves into the vacuum processing chamber;   a plurality of light receiving units for receiving plasma emission near a surface of the substrate from a side surface of the vacuum processing chamber, wherein the light receiving units are disposed so that the lengths of optical paths received by the respective light receiving units vary;   a plasma emission distribution measurement system disposed separately from the plurality of light receiving units; and   a means for computing a radical distribution in the plasma based on at least either the plasma emission distribution measurement system or the plurality of light receiving units; wherein   the plasma etching apparatus further includes a process for performing a plasma etching process in advance, a process for computing the radical distribution in the plasma during the process using the means for computing radical distribution and the plurality of light receiving units, and a process for measuring a CD shift distribution of the substrate subjected to plasma processing in the plasma etching process and storing the result thereof in a database;   a means for computing the radical distribution in the plasma using the plurality of light receiving units during a plasma etching process performed subsequent to said plasma etching process performed in advance; and   a means for controlling the plasma etching process conditions based on the data stored in the database.   
   
   
       2 . The plasma etching apparatus according to  claim 1 , wherein
 an object for controlling the processing condition during the plasma etching process is either a composition and flow rate of the processing gas supplied through the plurality of gas inlets or a temperature distribution of the supporting surface of the substrate holder, or both.   
   
   
       3 . The plasma etching apparatus according to  claim 1  or  claim 2 , including a means for computing the radical distribution in the plasma using the plurality of light receiving units during a plasma etching process performed subsequent to said plasma etching process performed in advance, and a means for controlling the plasma etching process conditions based on the data stored in the database; wherein
 the process for computing the radical distribution in the plasma and the process for controlling the plasma etching process conditions are performed at a timing selected from the following; per lot, per processing of the substrate, or per step of the plurality of etching steps; or the plasma etching process conditions is controlled immediately based on the computed result of the radical distribution in the plasma.