Plating method, semiconductor device manufacturing method and plate processing system

Abstract

A plating film is formed by the steps of applying a direct current between a cathode and an anode (S 10 ); superimposing an alternating current component on the direct current between the cathode and the anode and detecting a displacement current flowing between the cathode and the anode (S 12 to S 16 ); calculating a variation of a surface area of the plating film based on the displacement current (S 18 and S 20 ); and controlling the value of the direct current based on the variation of the surface area of the plating film so that the local area current density for the surface area does not change (S 22 and S 24 ). Consequently favorable film properties are provided to the plating film.

1 . A plating method comprising the steps of:
 applying a direct current between a cathode and an anode to form a plating filter on the cathode;   superimposing an alternating current component on the direct current between the cathode and the anode, and   detecting a displacement current flowing between the cathode and the anode;   calculating a variation of a surface area of the plating film based on the displacement current; and   controlling a value of the direct current based on the variation of the surface area of the plating film so that a current density for the plating film does not change in the step of forming a plating film.   
     
     
         2 . The plating method according to  claim 1 , wherein the step of controlling a value of the direct current comprises controlling timing so as to prevent subsequent processing for changing the direct current from being performed for a predetermined period of time after changing the direct current. 
     
     
         3 . The plating method according to  claim 1 , wherein the step of controlling a value of the direct current comprises changing the value of the direct current when the variation of the surface area of the plating film exceeds a predetermined reference value as a result of the step of calculating a variation of the surface area of the plating film. 
     
     
         4 . The plating method according to  claim 1 , wherein the step of calculating a variation of a surface area of the plating film comprises calculating the variation of the surface area of the plating film based on an average variation value of the displacement current for a predetermined period of time. 
     
     
         5 . The plating method according to  claim 1 , wherein the alternating current component has a frequency of not less than 10 kHz. 
     
     
         6 . A semiconductor device manufacturing method, the method comprising a plating step of filling a plurality of recesses provided in an insulating film formed on a substrate with a conductive material via plate processing,
 the plating processing step including:   applying a direct current between a cathode and an anode to form a plating film on the conductive material formed on a surface of the recesses, using the conductive material as the cathode;   superimposing an alternating current component on the direct current between the cathode and the anode, and detecting a displacement current flowing between the cathode and the anode;   calculating a variation of a surface area of the plating film based on the displacement current; and   controlling a value of the direct current based on the variation of the surface area of the plating film so that a current density for the plating film does not change in the step of forming a plating film.   
     
     
         7 . The semiconductor device manufacturing method according to  claim 6 , wherein the step of controlling a value of the direct current comprises controlling timing so as to prevent subsequent processing for changing the direct current from being performed for a predetermined period of time after changing the direct current. 
     
     
         8 . The semiconductor device manufacturing method according to  claim 6 , wherein the step of controlling a value of the direct current comprises changing the value of the direct current when the variation of the surface area of the plating film exceeds a predetermined reference value as a result of the step of calculating a variation of the surface area of the plating film. 
     
     
         9 . The semiconductor device manufacturing method according to  claim 6 , wherein the step of calculating a variation of a surface area of the plating film comprises calculating the variation of the surface area of the plating film based on an average variation value of the displacement current for a predetermined period of time. 
     
     
         10 . The semiconductor device manufacturing method according to  claim 6 , wherein the alternating current component has a frequency of not less than 10 kHz. 
     
     
         11 . A plate processing system comprising:
 a direct current source that applies a direct current between a cathode and an anode to form a plating film on the cathode;   an alternating current source that superimposes an alternating current component on the direct current between the cathode and the anode;   a surface area calculation unit that detects a displacement current flowing between the cathode and the anode, based on the alternating current component and calculates a variation of a surface area of the plating film that is being subjected to plate processing, based on the displacement current; and   a current control unit that controls a current value of the direct current based on the valuation of the surface area of the plating film so that a current density for the plating film that is being subjected to the plate processing does not change.   
     
     
         12 . The plate processing system according to  claim 11 , further comprising a timing control unit that controls timing for performing subsequent processing for changing the direct current after the current control unit changing the direct current. 
     
     
         13 . The plate processing system according to  claim 11  wherein the current control unit changes the value of the direct current when the variation of the surface area of the plating film calculated by the surface area calculation unit exceeds a predetermined reference value. 
     
     
         14 . The plate processing system according to  claim 11 , wherein the surface area calculation unit calculates the variation of the surface area of the plating film based on an average variation value of the displacement current for a predetermined period of time. 
     
     
         15 . The plate processing system according to  claim 11 , wherein the alternating current component superimposed by the alternating current source has a frequency of not less than 10 kHz. 
     
     
         16 . The plate processing system according to  claim 11 , wherein the cathode comprises a conductive material formed on a surface of a plurality of recesses provided in an insulating film formed on a substrate.