Placing table structure

Abstract

Provided is a placing table structure which is disposed in a processing container and has a subject to be processed thereon so as to form a thin film on the subject in the processing container by using raw material gas which generates thermal decomposition reaction having reversibility. The placing table structure is provided with a placing table for placing the subject to be processed on a placing surface, i.e., an upper surface of the placing table structure, and a decomposition restraint gas supply means which is arranged in the placing table for the purpose of supplying decomposition restraint gas, which restraints thermal decomposition of the raw material gas, toward a peripheral section of the subject placed on the placing surface of the placing table.

1 . A placing table structure comprising:
 a placing table provided in a processing container and configured to place a subject to be processed on a placing surface, which is a top surface of the placing table when a thin film is formed on the subject by using a raw material gas causing a reversible thermal decomposition reaction; and   a decomposition restraint gas feeding unit installed in the placing table to feed a decomposition restraint gas, which restrains a thermal decomposition of the raw material gas, to a peripheral portion of the subject placed on the placing surface of the placing table.   
     
     
         2 . The placing table structure of  claim 1 , wherein the decomposition restraint gas feeding unit comprises:
 a gas discharge port formed along a circumference of the placing table corresponding to the peripheral portion of the subject placed on the placing surface of the placing table;   a gas path communicated with the gas discharge port; and   a decomposition restraint gas source connected to the gas path to store a decomposition restraint gas.   
     
     
         3 . The placing table structure of  claim 2 , wherein the gas discharge port is communicated with the gas path through an annular diffusion chamber formed in the placing table along the circumference of the placing table. 
     
     
         4 . The placing table structure in  claim 2 , wherein the gas discharge port includes an annular slit formed along the circumference of the placing table. 
     
     
         5 . The placing table structure in  claim 2 , wherein the gas discharge port includes a plurality of discharged holes formed along the circumference of the placing table in a predetermined interval. 
     
     
         6 . The placing table structure in  claim 1 , wherein a recess is formed in the placing surface to receive the subject to be processed therein, and the recess has a depth corresponding to a thickness of the subject to be processed. 
     
     
         7 . The placing table structure in  claim 1 , wherein the placing surface is formed in the circumference thereof with an annular groove to define a gas staying space to temporally maintain the decomposition restraint gas. 
     
     
         8 . The placing table structure in  claim 1 , wherein the placing table is provided with a ring member having a shape of a thin ring plate, and positioned at an outer peripheral portion of the subject to be processed. 
     
     
         9 . The placing table structure of  claim 8 , wherein the ring member is movable up and down, and serves as a clamp ring having an inner peripheral portion of the ring member making contact with a top surface of the peripheral portion of the subject to be processed to press the subject. 
     
     
         10 . The placing table structure of  claim 8 , wherein the ring member serves as a cover ring to prevent the thin film from being formed on a region where the ring member is disposed. 
     
     
         11 . The placing table structure in  claim 1 , wherein the placing table is provided therein with a heating unit to heat the subject to be processed. 
     
     
         12 . The placing table structure in  claim 1 , wherein the decomposition restraint gas has a composition identical to a composition of a gas generated through a thermal decomposition reaction of the raw material gas. 
     
     
         13 . The placing table structure in  claim 1 , wherein the raw material gas includes a metal carbonyl raw material gas. 
     
     
         14 . The placing table structure of  claim 13 , wherein the metal carbonyl raw material gas includes at least one of elements selected from the group consisting of Ru 3 (CO) 12 , W(CO) 6 , Ni(CO) 4 , Mo(CO) 6 , Co 2 (CO) 8 , Rh 4 (CO) 12 , Re 2 (CO) 10 , Cr(CO) 6 , Os 3 (CO) 12  and Ta(CO) 5 . 
     
     
         15 . A thin film forming apparatus to form a thin film on a subject to be processed, the thin film forming apparatus comprising:
 a processing container having a gas exhaust function;   a placing table structure claimed in  claim 1 ; and   a gas feeding unit to feed a raw material gas causing a reversible thermal decomposition reaction to the processing container.   
     
     
         16 . A method of forming a thin film on a subject to be processed comprising:
 feeding a decomposition restraint gas toward a peripheral portion of the subject to be processed placed on a placing table in a processing container when a raw material gas causing a reversible thermal decomposition reaction is fed to the subject to be processed, thereby restraining a thermal decomposition of the raw material gas.   
     
     
         17 . The method of  claim 16 , wherein the raw material gas includes a metal carbonyl raw material gas. 
     
     
         18 . The method of  claim 17 , wherein the metal carbonyl raw material gas includes at least one of elements selected from the group consisting of Ru 3 (CO) 12 , W(CO) 6 , Ni(CO) 4 , Mo(CO) 6 , Co 2 (CO) 8 , Rh 4 (CO) 12 , Re 2 (CO) 10 , Cr(CO) 6 , Os 3 (CO) 12  and Ta(CO) 5 .