Flattening Method and Flattening Apparatus

Abstract

A flattening method can flatly process a surface of a metal film as an interconnect material over the entire film surface at a sufficiently high processing rate even when the metal film has initial surface irregularities. The flattening method for processing and flattening a surface of a metal film formed on a workpiece and having initial surface irregularities, including: coating only recessed portions of the initial surface irregularities of the metal film with a solid or pasty coating material; and processing the surface of the metal film by electrolytic processing using no abrasive.

1 . A flattening method for processing and flattening a surface of a metal film formed on a workpiece and having initial surface irregularities, comprising:
 coating only recessed portions of the initial surface irregularities of the metal film with a pasty coating material; and   processing the surface of the metal film by electrolytic processing.   
     
     
         2 . The flattening method according to  claim 1  further comprising removing the coating material which has not been processed by the electrolytic processing and remains on the surface of the metal film, and further processing the surface of the metal film. 
     
     
         3 . The flattening method according to  claim 1 , wherein the coating material is an insulating material having a resistivity of not less than 10 6  Ω·cm or a conductive material having a resistivity of not more than 10 3  Ω·cm. 
     
     
         4 . The flattening method according to  claim 1 , wherein only the recessed portions of the initial surface irregularities of the metal film are coated with the coating material by applying the coating material onto the entire surface of the metal film, and then removing only the coating material lying on the raised portions of the initial surface irregularities. 
     
     
         5 . The flattening method according to  claim 1 , wherein only the recessed portions of the initial surface irregularities of the metal film are coated with the coating material by selectively applying the coating material onto the recessed portions of the metal film. 
     
     
         6 . The flattening method according to  claim 1 , wherein the processing of the surface of the metal film by the electrolytic processing is carried out by:
 applying a voltage between a processing electrode, disposed close to the metal film of the workpiece, and a feeding electrode for feeding electricity to the metal film;   supplying a liquid into the space between the workpiece and at least one of the processing electrode and the feeding electrode, in which space a processing member is present; and   moving the workpiece relative to at least one of the processing electrode and the feeding electrode.   
     
     
         7 . The flattening method according to  claim 6 , wherein the processing member is composed of an ion exchanger or a material containing an ion exchanger. 
     
     
         8 . The flattening method according to  claim 6 , wherein the processing of the surface of the metal film by the electrolytic processing is carried out by bringing a contact member, disposed beside the processing electrode and/or the feeding electrode, into contact with the metal film surface. 
     
     
         9 . The flattening method according to  claim 1 , wherein the processing of the surface of the metal film by the electrolytic processing is carried out by:
 applying a voltage between a processing electrode, disposed close to the metal film of the workpiece, and a feeding electrode for feeding electricity to the metal film;   supplying a liquid between the workpiece and at least one of the processing electrode and the feeding electrode; and   moving the workpiece relative to at least one of the processing electrode and the feeding electrode.   
     
     
         10 . The flattening method according to  claim 9 , wherein the processing of the surface of the metal film by the electrolytic processing is carried out by bringing a contact member, disposed beside the processing electrode and/or the feeding electrode, into contact with the metal film surface. 
     
     
         11 . A flattening apparatus comprising:
 a coating material processing apparatus for coating only recessed portions of initial surface irregularities of a metal film with a pasty coating material; and   an electrolytic processing apparatus for processing the surface of the metal film by electrolytic processing.   
     
     
         12 . The flattening apparatus according to  claim 11 , wherein the coating material processing apparatus comprises a resist processing apparatus. 
     
     
         13 . A flattening method for polishing and flattening a surface of a metal film formed on a workpiece and having a pattern region and a field region, comprising:
 carrying out a first polishing of the metal film surface in such a manner that the polishing rate of the metal film in the pattern region is higher than the polishing rate of the metal film in the field region; and   carrying out a second polishing of the metal film surface in such a manner that the polishing rate of the metal film in the field region is higher than the polishing rate of the metal film in the pattern region.   
     
     
         14 . The flattening method according to  claim 13 , wherein at least one of the first polishing and the second polishing is carried out by electrolytic processing. 
     
     
         15 . The flattening method according to  claim 13 , wherein the first polishing and the second polishing are carried out by:
 applying a voltage between a processing electrode, disposed close to the surface of the metal film of the workpiece, and a feeding electrode for feeding electricity to the metal film;   supplying a liquid into the space between the workpiece and at least one of the processing electrode and the feeding electrode, in which space a processing member is present, and   moving the workpiece relative to at least one of the processing electrode and the feeding electrode.   
     
     
         16 . The flattening method according to  claim 15 , wherein the processing member is composed of an ion exchanger or a material containing an ion exchanger. 
     
     
         17 . The flattening method according to  claim 15 , wherein the first polishing is carried out while keeping the processing member in contact with the pattern region, and the second polishing is carried out while keeping the processing member contactless with the pattern region. 
     
     
         18 . The flattening method according to  claim 15 , wherein the first polishing is carried out while keeping the processing member in contact with the pattern region, and a resistance-forming processing of the pattern region is carried out prior to or simultaneously with the second polishing. 
     
     
         19 . The flattening method according to  claim 15 , wherein the second polishing is carried out while keeping the processing member contactless with the pattern region and simultaneously carrying out a resistance-forming processing of the pattern region. 
     
     
         20 . The flattening method according to  claim 15 , wherein at least one of the first polishing and the second polishing is carried out while keeping a contact member, disposed in the vicinity of the processing electrode and/or the feeding electrode, in contact with the surface of the metal film of the workpiece. 
     
     
         21 . The flattening method according to  claim 13 , wherein the first polishing and the second polishing are carried out respectively by:
 applying a voltage between a processing electrode, disposed close to or in contact with the metal film of the workpiece, and a feeding electrode for feeding electricity to the metal film;   supplying a liquid between the workpiece and at least one of the processing electrode and the feeding electrode; and   moving the workpiece relative to at least one of the processing electrode and the feeding electrode.   
     
     
         22 . The flattening method according to  claim 21 , wherein a resistance-forming processing of the pattern region is carried out prior to or simultaneously with the second polishing. 
     
     
         23 . The flattening method according to  claim 21 , wherein the second polishing is carried out while keeping the processing electrode contactless with the pattern region and simultaneously carrying out a resistance-forming processing of the pattern region. 
     
     
         24 . The flattening method according to  claim 21 , wherein at least one of the first polishing and the second polishing is carried out while keeping a contact member, disposed in the vicinity of the processing electrode and/or the feeding electrode, in contact with the surface of the metal film of the workpiece. 
     
     
         25 . The flattening method according to  claim 21 , wherein at least one of the first polishing and the second polishing is carried out while keeping the processing electrode at a distance of 0.05 to 50 μm from the surface of the metal film of the workpiece. 
     
     
         26 . The flattening method according to  claim 13 , wherein the end point of the first polishing is detected by time management, detection of a table current, or image recognition. 
     
     
         27 . A flattening apparatus comprising:
 a first polishing section for polishing a surface of a metal film, formed on a workpiece and having a pattern region and a field region, in such a manner that the polishing rate of the metal film in the pattern region is higher than the polishing rate of the metal film in the field region; and   a second polishing section for polishing the metal film surface in such a manner that the polishing rate of the metal film in the field region is higher than the polishing rate of the metal film in the pattern region.   
     
     
         28 . The flattening apparatus according to  claim 27 , wherein at least one of the first polishing section and the second polishing section carries out polishing by electrolytic processing. 
     
     
         29 . A flattening method for processing and flattening a surface of a metal film formed on a workpiece and having initial surface irregularities, comprising:
 coating only recessed portions of the initial surface irregularities of the metal film with a solid or pasty insulating coating material having a resistivity of not less than 10 6  Ω·cm; and   processing the surface of the metal film by electrolytic processing.   
     
     
         30 . The flattening method according to  claim 29  further comprising removing the coating material which has not been processed by the electrolytic processing and remains on the surface of the metal film, and further processing the surface of the metal film. 
     
     
         31 . A flattening apparatus comprising:
 a coating material processing apparatus for coating only recessed portions of initial surface irregularities of a metal film with a solid or pasty insulating coating material having a resistivity of not less than 10 6  Ω·cm; and   an electrolytic processing apparatus for processing the surface of the metal film by electrolytic processing.