Plasma processing apparatus and plasma processing method

Abstract

In a plasma processing apparatus for plasma-processing a silicon wafer 6 to which a protective film 6 a is stuck in a state that the silicon wafer 6 is held by a first electrode 3 by electrostatic absorption and is being cooled, the top surface 3 g of the first electrode 3 consists of a top surface central area A that is inside a boundary line P 2 that is distant inward by a prescribed length from the outer periphery P 1 of the silicon wafer 6 and in which the conductor is exposed, and a ring-shaped top surface peripheral area B that surrounds the top surface central area A and in which the conductor is covered with an insulating coating 3 f . This structure makes it possible to hold the silicon wafer 6 by sufficient electrostatic holding force by bringing the silicon wafer 6 into direct contact with the conductor and to increase the cooling efficiency by virtue of heat conduction from the silicon wafer 6 to the first electrode 3.

1 . A plasma processing apparatus for plasma-processing a surface of a substrate having an insulating layer on a front surface that is accommodated in a processing room, comprising: 
 an electrode that is a conductor and has a top surface that is greater in external size than the substrate;    cooling means for cooling the electrode;    a DC power section for applying a DC voltage to the electrode to cause the top surface of the electrode to hold the substrate by electrostatic absorption;    pressure lowering means for lowering pressure inside the processing room;    a plasma generation gas supply section for supplying a plasma generation gas to the processing room; and    a radio-frequency power section for generating plasma in the processing room by applying a radio-frequency voltage to the electrode,    wherein the top surface of the electrode has a top surface central area that is inside a boundary line that is distant inward by a prescribed length from an outer periphery of the substrate and in which the conductor is exposed, and a ring-shaped top surface peripheral area that surrounds the top surface central area and in which the conductor is covered with an insulating coating.    
   
   
       2 . The plasma processing apparatus according to  claim 1 , wherein an outer peripheral portion of the insulating layer of the substrate being held by the top surface of the electrode is in contact with the insulating coating in an area between the outer periphery and the boundary line.  
   
   
       3 . The plasma processing apparatus according to  claim 1 , comprising an insulating portion that covers an outer peripheral portion of the insulating coating in ring form.  
   
   
       4 . The plasma processing apparatus according to  claim 1 , wherein the insulating coating extends to cover part of a side surface of the electrode.  
   
   
       5 . The plasma processing apparatus according to  claim 1 , wherein the insulating coating is made of alumina.