Method of improving lifetime of etching liquid and yield in cu-interconnection process and cu-interconnection etching device

Abstract

A Cu-interconnection etching device includes an etching liquid tank containing therein an etching liquid that is a hydrogen peroxide based solution, a first concentration monitoring device receiving the etching liquid from the etching liquid tank and measuring a copper ion concentration of the etching liquid. The etching liquid is supplied through a filter assembly that filters off copper ions contained in the etching liquid so as to provide a filtered etching liquid. The filter etching liquid is supplied through a second concentration monitoring device that measures a copper ion concentration of the filtered etching liquid and conducts the filtered etching liquid back to the etching liquid tank. A variation between the measurements of the first and second concentration monitoring devices is used to control the operation of the filter assembly in order to maintain a proper level of copper ion concentration in the etching liquid.

What is claimed is: 
     
         1 . A Cu-interconnection etching device, comprising:
 an etching liquid tank containing therein an etching liquid;   a first concentration monitoring device that measures a copper ion concentration of the etching liquid in the etching liquid tank and operating a filter assembly arranged downstream the etching liquid tank to receive the etching liquid from the etching liquid tank and filtering copper ions from the etching liquid received thereby so as to provide a filtered etching liquid; and   a second concentration monitoring device that is arranged downstream the filter assembly to measure a copper ion concentration of the filtered etching liquid and conducts the filtered etching liquid back to the etching liquid tank,   wherein the first concentration monitoring device provides a first measurement of copper ion concentration of the etching liquid that is measured upstream the filter and the second concentration monitoring device provides a second measurement of copper ion concentration of the filtered etching liquid that is measured downstream the filter and a variation between the first and second measurements is applied to control the operation of the filter assembly for filtering copper ions from the etching liquid received from the etching liquid tank.   
     
     
         2 . The Cu-interconnection etching device as claimed in  claim 1  further comprising a liquid pump connected to the etching liquid tank and the filter assembly is connected to the liquid pump to allow the liquid pump to supply the etching liquid from the etching liquid tank to the filter assembly via the first concentration monitoring device. 
     
     
         3 . The Cu-interconnection etching device as claimed in  claim 2 , wherein the first concentration monitoring device is arranged in the etching liquid tank and located between the etching liquid tank and the liquid pump or between the liquid pump and the filter assembly. 
     
     
         4 . The Cu-interconnection etching device as claimed in  claim 1 , wherein the second concentration monitoring device is located between the filter assembly and the etching liquid tank. 
     
     
         5 . The Cu-interconnection etching device as claimed in  claim 1 , wherein the etching liquid comprises a hydrogen peroxide based solution. 
     
     
         6 . The Cu-interconnection etching device as claimed in  claim 5 , wherein the first concentration monitoring device further monitors a concentration of hydrogen peroxide of the etching liquid received from the etching liquid tank and the second concentration monitoring device further monitors a concentration of hydrogen peroxide of the filtered etching liquid. 
     
     
         7 . The Cu-interconnection etching device as claimed in  claim 5 , wherein the etching liquid comprises a hydrogen peroxide based solution and an additive. 
     
     
         8 . The Cu-interconnection etching device as claimed in  claim 7 , wherein the first concentration monitoring device further monitors a concentration of hydrogen peroxide and a concentration of the additive of the etching liquid received from the etching liquid tank and the second concentration monitoring device further monitors a concentration of hydrogen peroxide and a concentration of the additive of the filtered etching liquid. 
     
     
         9 . The Cu-interconnection etching device as claimed in  claim 1 , wherein the filter assembly comprises one filter. 
     
     
         10 . The Cu-interconnection etching device as claimed in  claim 1 , wherein the filter assembly comprises a plurality of filters connected in series and the control of the operation of the filter assembly comprises selectively activating a specific number of filters among the plurality of filters while keeping a remaining number of filters of the plurality of filters deactivated, wherein the specific number is determined according to the variation between the first and second measurements. 
     
     
         11 . The Cu-interconnection etching device as claimed in  claim 10 , wherein each of the filters comprises one or more reverse osmosis membranes connected in series. 
     
     
         12 . The Cu-interconnection etching device as claimed in  claim 10 , wherein each of the filters comprises one or more filter fabrics connected in series. 
     
     
         13 . The Cu-interconnection etching device as claimed in  claim 10 , wherein each of the filters comprises multiple reverse osmosis membranes and multiple filter fabrics connected in series. 
     
     
         14 . The Cu-interconnection etching device as claimed in  claim 9 , wherein the filter comprises one or more reverse osmosis membranes connected in series. 
     
     
         15 . The Cu-interconnection etching device as claimed in  claim 9 , wherein the filter comprises one or more filter fabrics connected in series. 
     
     
         16 . The Cu-interconnection etching device as claimed in  claim 9 , wherein the filter comprises multiple reverse osmosis membranes and multiple filter fabrics connected in series. 
     
     
         17 . A Cu-interconnection etching device, comprising:
 an etching liquid tank containing therein an etching liquid;   a first concentration monitoring device that measures a copper ion concentration of the etching liquid in the etching liquid tank and operating a filter assembly arranged downstream the etching liquid tank to receive the etching liquid from the etching liquid tank and filtering copper ions from the etching liquid received thereby so as to provide a filtered etching liquid; and   a second concentration monitoring device that is arranged downstream the filter assembly to measure a copper ion concentration of the filtered etching liquid and conducts the filtered etching liquid back to the etching liquid tank,   wherein the first concentration monitoring device provides a first measurement of copper ion concentration of the etching liquid that is measured upstream the filter and the second concentration monitoring device provides a second measurement of copper ion concentration of the filtered etching liquid that is measured downstream the filter and a variation between the first and second measurements is applied to control the operation of the filter assembly for filtering copper ions from the etching liquid received from the etching liquid tank; and   wherein the filter assembly comprises a plurality of filters connected in series and the control of the operation of the filter assembly comprises selectively activating a specific number of filters among the plurality of filters while keeping a remaining number of filters of the plurality of filters deactivated, wherein the specific number is determined according to the variation between the first and second measurements.   
     
     
         18 . The Cu-interconnection etching device as claimed in  claim 17 , wherein each of the filters comprises one or more reverse osmosis membranes connected in series. 
     
     
         19 . The Cu-interconnection etching device as claimed in  claim 17 , wherein each of the filters comprises one or more filter fabrics connected in series. 
     
     
         20 . The Cu-interconnection etching device as claimed in  claim 17 , wherein each of the filters comprises multiple reverse osmosis membranes and multiple filter fabrics connected in series.