Method of substrate temperature control and method of assessing substrate temperature controllability

Abstract

A method of substrate temperature control for plasma processing apparatus in which a substrate which is being held on a substrate holder in a process chamber is being processed, and He gas is passed through the gap between the substrate and the substrate mounting surface during the processing of the substrate, the substrate temperature is controlled by the thermal transfer characteristics of the gas and the substrate is cooled to the prescribed temperature, and the pressure of the He gas is preset by a pressure setting part 50 a, the actual pressure is measured with a pressure gauge 49, and the gas flow rate is controlled in such a way that the measured pressure becomes equal to the set pressure by a pressure control valve 46. Furthermore, the substrate temperature controllability is assessed by monitoring the gas flow rate with a substrate temperature controllability assessment part 50 b.

What is claimed is:  
     
         1 . A method of substrate temperature control, comprising the steps of: 
 measuring the pressure of a heat transfer gas flowing in a gap between a substrate and a substrate mounting surface of a substrate holder;    controlling a flow rate of the heat transfer gas in such a way that the measured pressure of the heat transfer gas becomes equal to a preset pressure.    
     
     
         2 . The method of substrate temperature control according to    claim 1   , wherein a pressure control valve which is established in the heat transfer gas flow way has a set pressure signal input from a pressure setting part and a measured pressure input from a pressure gauge, and the flow rate of the heat transfer gas is controlled such that the measured pressure becomes equal to the set pressure.  
     
     
         3 . The method of substrate temperature control according to    claim 1   , further comprising the step of holding the substrate on an electrostatic chucking stage which is included in the substrate holder.  
     
     
         4 . A method of assessing a substrate condition, comprising the steps of: 
 measuring the pressure of a heat transfer gas which is flowing in a gap between a substrate and a substrate mounting surface of a substrate holder;    controlling the flow rate of the heat transfer gas such that the measured pressure of the heat transfer gas becomes equal to a preset pressure;    assessing a state of the gap between the substrate and the substrate mounting surface on a basis of a comparison of the heat transfer gas flow rate with a standard value.    
     
     
         5 . The method of assessing a substrate condition according to    claim 4   , wherein the substrate holder includes an electrostatic chucking stage, and temperature controllability of the substrate is assessed by assessing a state of electrostatic force between the substrate and the electrostatic chucking stage.