Plating apparatus

Abstract

Provided is a plating apparatus to determine appropriate control parameters for forming plating with high film thickness flatness on a substrate. The plating apparatus includes an estimation unit that estimates a density of a current flowing through an outer edge of the substrate, a current density calculation unit that calculates a density of a plating current flowing through a plating solution into the substrate based on the estimated current density, and a control parameter that specifies an operation mode of the plating apparatus, the current density calculation unit calculating the plating current density for each of a plurality of different operation modes of the plating apparatus, a film thickness calculation unit that calculates a thickness of a plating film formed on the substrate for each of the plurality of operation modes, based on each calculated plating current density, and a control parameter determination unit that determines a control parameter corresponding to an optimal operation mode, based on the calculated plating film thickness for each operation mode of the plating apparatus.

What is claimed is: 
     
         1 . A plating apparatus for plating a substrate, comprising:
 a plating tank to store a plating solution,   a substrate holder that holds the substrate,   an anode disposed in the plating tank to oppose the substrate held by the substrate holder,   a potential sensor disposed in the vicinity of the substrate held by the substrate holder and configured to measure a potential of the plating solution,   an estimation unit configured to estimate a density of a current flowing through an outer edge of the substrate based on a value of the potential of the plating solution that is measured by the potential sensor,   a current density calculation unit configured to calculate a density of a plating current flowing through the plating solution into the substrate, based on the estimated current density and a control parameter that specifies an operation mode of the plating apparatus, the current density calculation unit calculating the plating current density for each of a plurality of different operation modes of the plating apparatus,   a film thickness calculation unit configured to calculate a thickness of a plating film formed on the substrate for each of the plurality of operation modes, based on each of the plating current densities calculated by the current density calculation unit, and   a control parameter determination unit configured to determine a control parameter corresponding to an optimal operation mode, based on the plating film thickness for each operation mode of the plating apparatus that is calculated by the film thickness calculation unit, the plating apparatus performing a plating process on the substrate by use of the control parameter determined by the control parameter determination unit.   
     
     
         2 . The plating apparatus according to  claim 1 , wherein the operation mode of the plating apparatus is specified by a combination of a plurality of types of control parameters, and
 the current density calculation unit is configured to calculate the plating current density for each set of the plurality of types of control parameters, and   the control parameter determination unit is configured to determine a set of control parameters corresponding to an optimal operation mode, based on the plating film thickness for each operation mode of the plating apparatus that is calculated by the film thickness calculation unit.   
     
     
         3 . The plating apparatus according to  claim 2 , wherein the control parameter is a parameter for one or more of i) rotation of the substrate, ii) partial shielding of the substrate, iii) stirring of the plating solution, and iv) a set value of a current flowing between the substrate and the anode. 
     
     
         4 . The plating apparatus according to  claim 1 , wherein the control parameter determination unit is configured to determine the control parameter based on flatness of the calculated plating film thickness. 
     
     
         5 . The plating apparatus according to  claim 1 , wherein the estimation unit is implemented as a state space model configured to estimate the current density by use of a state equation and an observation equation, the state equation being an equation describing time evolution on the density of the current flowing through the outer edge of the substrate, the observation equation being an equation describing a relation between the density of the current flowing through the outer edge of the substrate and the potential of the plating solution at a position of the potential sensor. 
     
     
         6 . The plating apparatus according to  claim 5 , comprising a plating module including at least the plating tank, the substrate holder, the anode and the potential sensor, wherein the relation between the current density and the potential of the plating solution is based on a function representing a 3D model of the plating module. 
     
     
         7 . The plating apparatus according to  claim 5 , wherein the state space model further includes a Kalman filter configured to correct estimation results of the density of the current flowing through the outer edge of the substrate, based on the value measured by the potential sensor. 
     
     
         8 . The plating apparatus according to  claim 1 , wherein the outer edge of the substrate is a portion to be gripped with the substrate holder of the substrate. 
     
     
         9 . The plating apparatus according to  claim 8 , wherein the plating current density calculated by the current density calculation unit is a density of a current in a region inside the outer edge of the substrate.