Semiconductor substrate and lithographic mask processing

Abstract

A system and method for semiconductor processing using magnetorheological finishing (MRF) includes polishing of semiconductor substrates, ceramic bodies and glass lithography masks, to a high degree of flatness by the abrasive action of a magnetorheological fluid flowing in a magnetic field.

What is claimed is:  
     
         1 . A process for shaping a semiconductor wafer comprising: 
 positioning a silicon wafer having a surface in a fixturing device;    contacting the surface with a magnetorheological fluid in the presence of a magnetic field; and    shaping the surface of the silicon wafer to a predetermined degree of flatness.    
     
     
         2 . The process of  claim 1 , wherein positioning a silicon wafer having a surface in a fixturing device comprises positioning a silicon wafer in a vacuum stage, an electrostatic chuck, a clamp mount, a template assembly mount and a wax mount stage.  
     
     
         3 . The process of  claim 1 , wherein positioning a silicon wafer comprises positioning a prime silicon wafer.  
     
     
         4 . The process of  claim 1 , wherein shaping the surface of the silicon wafer comprises flattening the surface to a peak to valley flatness of less than about 0.05 micrometers.  
     
     
         5 . A process for shaping a perimeter surface of a semiconductor wafer comprising: 
 positioning a silicon wafer having a perimeter surface in a fixturing device,    wherein the wafer has opposing surfaces;    contacting at least the perimeter surface of the silicon wafer with a magnetorheological fluid in the presence of a magnetic field; and    simultaneously shaping the opposing surfaces and the perimeter surface to a predetermined degree of flatness.    
     
     
         6 . The process of  claim 5 , wherein simultaneously shaping the opposing surfaces of the perimeter surface comprises rotating at least the perimeter surface of the silicon wafer through the magnetorheological fluid in the presence of the magnetic field.  
     
     
         7 . A process for preparing a substrate comprising: 
 rough polishing a surface of the substrate using an abrasive polishing agent to create a spatial wavelength in the surface of the substrate;    positioning the substrate in a fixturing device;    contacting the surface with a magnetorheological fluid in the presence of a magnetic field; and    shaping the surface to a predetermined degree of flatness, such that the spatial wavelength of the surface is substantially preserved.    
     
     
         8 . The process of  claim 7 , wherein positioning a silicon wafer having a surface in a fixturing device comprises positioning a silicon wafer in a vacuum plate, an electrostatic chuck, a clamp mount, a template assembly mount and a wax mount stage.  
     
     
         9 . The process of  claim 7 , wherein the process for preparing a substrate comprises preparing a substrate selected from the group consisting of a semiconductor substrate, a glass substrate, and a ceramic substrate.  
     
     
         10 . A process for shaping a substrate carrier plate comprising: 
 positioning a substrate carrier plate having a workpiece surface in a fixturing device;    contacting the workpiece surface with a magnetorheological fluid in the presence of a magnetic field; and    shaping the workpiece surface to a predetermined degree of flatness.    
     
     
         11 . The process of  claim 10 , wherein shaping the workpiece surface comprises shaping the workpiece surface to substantially match the surface of a substrate to be placed on the workpiece surface prior to carrying out a polishing process.  
     
     
         12 . The process of  claim 11 , wherein positioning a substrate carrier plate having a workpiece surface in a fixturing device comprises positioning the substrate carrier plate in a fixturing device selected from the group consisting of a template assembly mount and a wax mount stage.  
     
     
         13 . A process for a glass lithographic mask comprising: 
 positioning a glass lithographic mask having a surface in a fixturing device;    contacting the surface with a magnetorheological fluid in the presence of a magnetic field; and    shaping the surface of the glass lithographic mask to a predetermined degree of flatness.    
     
     
         14 . The process of  claim 13 , wherein positioning a glass lithographic mask comprises positioning an ultra-violet lithographic mask.  
     
     
         15 . The process of  claim 13 , wherein shaping the surface of the glass lithographic mask comprises shaping the surface to a peak to valley flatness of no more than about 0.05 micrometers.