Methods and apparatus for electrically and/or chemically-mechanically removing conductive material from a microelectronic substrate

Abstract

A method and apparatus for removing conductive material from a microelectronic substrate. In one embodiment, a support member supports a microelectronic substrate relative to a material removal medium, which can include first and second electrodes and a polishing pad. One or more electrolytes are disposed between the electrodes and the microelectronic substrate to electrically link the electrodes to the microelectronic substrate. The electrodes are then coupled to a source of varying current that electrically removes the conductive material from the substrate. The microelectronic substrate and/or the electrodes can be moved relative to each other to position the electrodes relative to a selected portion of the microelectronic substrate, and/or to polish the microelectronic substrate. The material removal medium can remove gas formed during the process from the microelectronic substrate and/or the electrodes. The medium can also have different first and second electrical characteristics to provide different levels of electrical coupling to different regions of the microelectronic substrate.

1 - 35 . (Canceled)  
     
     
         36 . A method for removing electrically conductive material from a microelectronic substrate, comprising: 
 aligning a first portion of the microelectronic substrate with a first portion of a material removal medium having first electrical characteristics and aligning a second portion of the microelectronic substrate with a second portion of the material removal medium having second electrical characteristics different than the first electrical characteristics;    engaging the conductive material with a polishing surface of the material removal medium; and    removing at least a portion of the electrically conductive material from the microelectronic substrate by passing a varying electrical current through the conductive material while engaging the conductive material with the material removal medium and moving at least one of the microelectronic substrate and the material removal medium relative to the other.    
     
     
         37 . The method of  claim 36  wherein the microelectronic substrate has an edge surface and a face surface and wherein the method further comprises: 
 interposing the polishing surface between the face surface and first and second electrodes;    coupling at least one of the first and second electrodes to a source of electrical potential; and    electrically coupling the first and second electrodes to the face surface of the microelectronic substrate through the polishing surface of the polishing pad.    
     
     
         38 . The method of  claim 36  wherein aligning the first and second portions of the microelectronic substrate includes aligning the first portion of the microelectronic substrate with the first portion of the material removal medium having a first electrical characteristic and aligning the second portion of the microelectronic substrate with the second portion of the material removal medium having a second electrical characteristic different than the first electrical characteristic.  
     
     
         39 . The method of  claim 38 , further comprising selecting the first electrical characteristic to be a first conductivity and selecting the second electrical characteristic to be a second conductivity.  
     
     
         40 . The method of  claim 38 , further comprising selecting the first electrical characteristic to be a first dielectric constant and selecting the second electrical characteristic to be a second dielectric constant.  
     
     
         41 . The method of  claim 36 , further comprising engaging the first portion of the microelectronic substrate with a first electrolytic fluid and engaging a second portion of the microelectronic substrate with a second electrolytic fluid different than the first electrolytic fluid.  
     
     
         42 . The method of  claim 36 , further comprising engaging the first portion of the microelectronic substrate with a first electrolytic fluid having a first chemical concentration and engaging a second portion of the microelectronic substrate with a second electrolytic fluid having a second chemical concentration different than the first chemical concentration.  
     
     
         43 . The method of  claim 36 , further comprising engaging the first portion of the microelectronic substrate with a first electrolytic fluid having a first chemical composition and engaging a second portion of the microelectronic substrate with a second electrolytic fluid having a second chemical composition different than the first chemical composition.  
     
     
         44 . The method of  claim 36  wherein the first portion of the material removal medium has a first impedance and the second portion of the material removal medium has a second impedance different than the first impedance and wherein the method further includes forming a first electrical circuit that includes the first impedance and forming a second electrical circuit that includes the second impedance.  
     
     
         45 . The method of  claim 36  wherein the material removal medium includes a polishing pad having the polishing surface and at least one electrode disposed proximate to the polishing surface, and wherein the method includes aligning the first portion of the microelectronic substrate to directly face at least one of the electrodes without the polishing pad being interposed between the first portion and the at least one electrode, and wherein the method further includes aligning the second portion of the microelectronic substrate to directly face a portion of the polishing pad positioned between at least one of the electrodes and the microelectronic substrate.  
     
     
         46 . The method of  claim 36  wherein the material removal medium includes a polishing pad having the polishing surface and at least one electrode positioned proximate to the polishing surface, the polishing pad having first pores defining a first porosity and second pores defining a second porosity different than the first porosity, and wherein the method further comprises aligning the first portion of the microelectronic substrate with the first pores and aligning the second portion of the microelectronic substrate with the second pores.  
     
     
         47 . The method of  claim 36  wherein the material removal medium includes a polishing pad having the polishing surface and at least one electrode positioned proximate to the polishing surface, the polishing pad having a generally porous region and a generally non-porous region, and wherein the method further comprises aligning the first portion of the microelectronic substrate with the generally porous region and aligning the second portion of the microelectronic substrate with the generally non-porous region.  
     
     
         48 . A method for removing electrically conductive material from a microelectronic substrate, comprising: 
 aligning a first portion of the microelectronic substrate with a first portion of a material removal medium having first electrical characteristics and aligning a second portion of the microelectronic substrate with a second portion of the material removal medium having second electrical characteristics different than the first electrical characteristics; and    removing at least part of the electrically conductive material from the microelectronic substrate by passing a varying electrical current through the material removal medium and the conductive material.    
     
     
         49 . The method of  claim 48  wherein the microelectronic substrate has an edge surface and a face surface and wherein the method further comprises: 
 interposing a polishing surface between the face surface and first and second electrodes;    coupling at least one of the first and second electrodes to the source of electrical potential; and    electrically coupling the first and second electrodes to the face surface of the microelectronic substrate through the polishing surface of the polishing pad.    
     
     
         50 . The method of  claim 48  wherein the part of the electrically conductive material removed from the microelectronic substrate is a first part, and wherein the material removal medium includes a polishing surface, and wherein the method further comprises: 
 engaging the conductive material with the polishing surface of the material removal medium; and    moving at least one of the polishing surface and the microelectronic substrate relative to the other to remove a second part of the electrically conductive material.    
     
     
         51 . The method of  claim 48  wherein aligning the first and second portions of the microelectronic substrate includes aligning the first portion of the microelectronic substrate with the first portion of the material removal medium having a first dielectric constant and aligning the second portion of the microelectronic substrate with the second portion of the material removal medium having a second dielectric constant different than the first dielectric constant.  
     
     
         52 . The method of  claim 48 , further comprising engaging the first portion of the microelectronic substrate with a first electrolyte and engaging a second portion of the microelectronic substrate with a second electrolyte different than the first electrolyte.  
     
     
         53 . The method of  claim 48  wherein the material removal medium includes a polishing pad having a polishing surface and at least one electrode positioned proximate to the polishing surface, the polishing pad having first pores defining a first porosity and second pores defining a second porosity different than the first porosity, and wherein the method further comprises aligning the first portion of the microelectronic substrate with the first pores and aligning the second portion of the microelectronic substrate with the second pores.  
     
     
         54 . The method of  claim 48  wherein the material removal medium includes a polishing pad having a polishing surface and at least one electrode positioned proximate to the polishing surface, the polishing pad having a generally porous region and a generally non-porous region, and wherein the method further comprises aligning the first portion of the microelectronic substrate with the generally porous region and aligning the second portion of the microelectronic substrate with the generally non-porous region.  
     
     
         55 . A method for removing conductive material from a face surface of a microelectronic substrate, comprising: 
 electrically coupling a source of varying current to the conductive material on the face surface by coupling first and second electrodes to the source of varying current and facing the first and second electrodes toward the face surface of the microelectronic surface;    engaging the conductive material with a polishing pad having a polishing surface and moving at least one of the microelectronic substrate and the polishing surface relative to the other; and    controlling a rate and/or an amount of conductive material removed from the microelectronic substrate by controlling an interaction between the source of varying current and the conductive material and independently controlling an interaction between the polishing surface and the conductive material.    
     
     
         56 . The method of  claim 55  wherein controlling an amount of conductive material removed includes aligning a first portion of the microelectronic substrate with a first region of the polishing surface having a first dielectric constant and aligning a second portion of the microelectronic substrate with a second region of the polishing surface having a second dielectric constant different than the first dielectric constant.  
     
     
         57 . The method of  claim 55  wherein controlling an amount of conductive material removed includes controlling a normal force applied to the conductive material at an interface between the conductive material and the polishing surface.  
     
     
         58 . The method of  claim 55  wherein controlling an amount of conductive material removed includes controlling an amount, ionic strength, and/or pH of an electrolytic fluid between the conductive material and an electrode coupled to the source of varying current.  
     
     
         59 . The method of  claim 55  wherein controlling an amount of conductive material removed includes controlling a voltage, current, waveform, and/or frequency of an electrical signal applied to the microelectronic substrate.  
     
     
         60 . The method of  claim 55  wherein controlling an amount of conductive material removed includes controlling a relative velocity between the polishing pad and the microelectronic substrate, controlling a normal force between the polishing pad and the microelectronic substrate, and/or selecting a configuration of the polishing pad.  
     
     
         61 . The method of  claim 55 , further comprising removing gas from a region proximate to the microelectronic substrate.  
     
     
         62 . A method for removing electrically conductive material from a face surface of a microelectronic substrate, comprising: 
 engaging the conductive material with a first electrolytic fluid and a polishing surface of a material removal medium;    removing at least a first portion of the electrically conductive material from the microelectronic substrate by passing a varying electrical current from a first electrode facing the face surface, through the first electrolytic fluid and the first conductive material to a second electrode facing the face surface while engaging the first conductive material with the material removal medium and moving at least one of the microelectronic substrate and the material removal medium relative to the other;    engaging the conductive material with a second electrolytic fluid and the polishing surface of the material removal medium, the second electrolytic fluid being different than the first electrolytic fluid; and    removing at least a second portion of the electrically conductive material from the microelectronic substrate by passing a varying electrical current from the first electrode facing the face surface, through the second electrolytic fluid and the second conductive material to the second electrode facing the face surface while engaging the second conductive material with the material removal medium and moving at least one of the microelectronic substrate and the material removal medium relative to the other.    
     
     
         63 . The method of  claim 62 , further comprising selecting the first electrolytic fluid to have a first chemical concentration and selecting the second electrolytic fluid to have a second chemical concentration different than the first chemical concentration.  
     
     
         64 . The method of  claim 62 , further comprising selecting the first electrolytic fluid to have a first chemical composition and selecting the second electrolytic fluid to have a second chemical composition different than the first chemical composition.  
     
     
         65 - 107 . (Canceled)