Plasma Processing Apparatus And Plasma Processing Method

Abstract

A plasma processing apparatus and method which includes a vacuum processing chamber, a plasma generating unit, a process gas supply unit, a specimen table, and a vacuum pumping unit. The specimen table includes an electrostatic arrangement for holding a specimen on a holding surface of the specimen table, a specimen table cover made of an insulator arranged around the specimen table, and first and second heat transfer gas supply units. The first heat transfer gas supply unit has a main path for supplying a heat transfer gas to the specimen holding surface, and the second heat transfer gas supply unit has a branch path branched from the main path of the first heat transfer gas supply unit for directly supplying a part of the heat transfer gas to a gap between an outer portion of the specimen holding surface and the specimen table cover for cooling the specimen table cover.

1 . A plasma processing apparatus including a vacuum processing chamber, a plasma generating unit for generating a plasma in the vacuum processing chamber, a process gas supply unit for supplying gas to the vacuum process chamber, a metallic specimen table having a specimen holding surface for holding a specimen to be processed, and a vacuum pumping unit for evacuating the vacuum processing chamber;
 wherein the metallic specimen table comprises:   electrostatic means for holding the specimen on a holding surface of the metallic specimen table by electrostatic force;   a specimen table cover made of an insulator arranged in an upper portion of the metallic specimen table on an outer portion of the specimen holding surface so as to cover at least a part of an upper surface of the metallic specimen table disposed at a position facing and below the specimen for preventing discharge of undesired metals when the metallic specimen table is exposed to the plasma;   a first heat transfer gas supply unit having a main path inside of the metallic specimen table for supplying a heat transfer gas between the specimen holding surface and the specimen for cooling the specimen; and   a second heat transfer gas supply unit having a branch path formed inside of the metallic specimen table and branched from the main path inside of the metallic specimen table of the first heat transfer gas supply unit for supplying a part of the heat transfer gas from the main path directly to a closed gap between an outer portion of the upper surface of the specimen holding surface and the specimen table cover for cooling the specimen table cover.   
   
   
       2 . The plasma processing apparatus according to  claim 1 , comprising a gas sealing unit arranged between the upper portion of the outer portion of the specimen holding surface and the specimen table cover which covers at least the part of the upper surface of the metallic sample table disposed at the position facing and below the specimen so as to form the closed gap. 
   
   
       3 . The plasma processing apparatus according to  claim 1 , wherein the specimen table cover covers a portion of a sidewall surface of the metallic specimen table so as to delimit a portion of the closed gap thereat. 
   
   
       4 . A plasma processing method for processing a specimen by a plasma processing apparatus including a vacuum process chamber, a plasma generating unit for generating a plasma in the vacuum processing chamber, a process gas supply unit for supplying gas to the vacuum process chamber, a metallic specimen table including a specimen holding surface for holding a specimen to be processed, an electrostatic means for holding the specimen on the holding surface, and a specimen table cover made of an insulator arranged in an upper portion of the metallic specimen table on an outer portion of the specimen holding surface so as to cover at least a part of an upper surface of the metallic specimen table disposed at a position facing and below the specimen;
 wherein the processing method comprises the steps of:   holding the specimen on the holding surface of the metallic specimen table by an electrostatic force generated by the electrostatic means;   supplying a heat transfer gas between the specimen holding surface and the specimen for cooling the specimen through a main path inside of the metallic specimen table of a first heat transfer gas supply unit; and   supplying a part of the heat transfer gas from the main path directly to a closed gap between the outer portion of the specimen holding surface and the specimen table cover for cooling the specimen table cover through a branch path inside of the metallic specimen table of a second heat transfer gas supply unit and branched from the main path inside of the metallic specimen table of the first heat transfer gas supply unit;   whereby temperature fluctuation of the specimen table cover during processing of the specimen is restrained and discharge of undesired metals is prevented when the metallic specimen table is exposed to the plasma.   
   
   
       5 . The plasma processing method according to  claim 4 , wherein the specimen table cover covers a portion of a sidewall surface of the metallic specimen table so as to delimit a portion of the closed gaps thereat.