Automated process and apparatus for planarization of topographical surfaces

Abstract

An improved apparatus ( 20 ) and method are provided for effective, high speed contact planarization of coated curable substrates such as microelectronic devices to achieve very high degrees of planarization. The apparatus ( 20 ) includes a planarizing unit ( 28 ) preferably having an optical flat flexible sheet ( 88 ) and a backup optical flat body ( 82 ), and a curing assembly ( 30 ). In operation, a substrate ( 78 ) having a planarizable coating ( 76 ) is placed within a vacuum chamber ( 26 ) beneath sheet ( 88 ) and body ( 82 ). A pressure differential is created across sheet ( 88 ) so as to deflect the sheet into contact with a central region C of the coating ( 76 ), whereupon the coating ( 76 ) is brought into full planarizing contact with sheet ( 88 ) and body ( 82 ) by means of a support ( 114 ) and vacuum chuck ( 120 ); at this point the coating ( 76 ) is cured using assembly ( 30 ). After curing, a pressure differential is established across sheet ( 88 ) for sequentially separating the sheet from the peripheral portion P of the coating, and then full separation of the sheet ( 88 ) and coating ( 76 ).

1 . Apparatus for planarizing a curable coating applied to a substrate, said coating having a surface presenting a surface area with a central region and a surrounding peripheral region, said apparatus comprising: 
 a support operable to support and hold a thin, flexible sheet of material;    a support assembly operable to support and hold said substrate with said coating proximal to said sheet;    a differential pressure assembly operable to create a pressure differential across said sheet of sufficient magnitude to deflect the sheet so that the sheet contacts the central region of said surface area but is spaced from said peripheral region,    said support assembly shiftable to move said substrate into face-to-face planarizing contact with said sheet throughout substantially all of said surface area; and    a device for curing said coating during said planarizing contact.    
   
   
       2 . The apparatus of  claim 1 , said support comprising a pair of annular clamping rings operable to cooperatively clamp and hold the margin of said sheet.  
   
   
       3 . The apparatus of  claim 1 , said mounting assembly comprising a ring-like body sized to engage the periphery of a face of said substrate remote from said coating, and a piston and cylinder assembly operably coupled with the body for selective shifting thereof toward and away from said sheet.  
   
   
       4 . The apparatus of  claim 3 , said mounting assembly further including a shiftable compression member operable to press said coating into said planarizing contact with said sheet.  
   
   
       5 . The apparatus of  claim 4 , said compression member comprising a vacuum chuck, said chuck operably coupled with a vacuum source.  
   
   
       6 . The apparatus of  claim 1 , said differential pressure assembly including wall structure defining a first chamber in communication with the face of said sheet remote from said coating, and a second chamber in communication with the face of said sheet adjacent said coating.  
   
   
       7 . The apparatus of  claim 6 , including structure defining a vacuum port in communication with said first chamber in order to create vacuum conditions therein.  
   
   
       8 . The apparatus of  claim 6 , including structure defining a port in communication with said second chamber for selectively drawing a vacuum or establishing a positive pressure therein.  
   
   
       9 . The apparatus of  claim 1 , said mounting assembly also shiftable to move said substrate out of contact with said sheet after said curing of said coating.  
   
   
       10 . The apparatus of  claim 1 , including an optical flat body positioned adjacent the face of said sheet remote from said substrate, said sheet engageable with said optical flat body during said planarizing contact between said coating and said sheet.  
   
   
       11 . The apparatus of  claim 10 , said optical flat body operable to transmit said UV radiation therethrough.  
   
   
       12 . The apparatus of  claim 1 , including a resilient platen adjacent the face of said substrate remote from said coating, said platen being shiftable with said mounting assembly.  
   
   
       13 . The apparatus of  claim 1 , wherein said apparatus does not include an optical flat body.  
   
   
       14 . Apparatus for planarizing a curable coating applied to a substrates said coating having a surface presenting a surface area with a central region and a surrounding peripheral region, said apparatus comprising: 
 means for positioning a thin, flexible sheet of material in proximal spaced relationship to said surface;    means for causing said sheet to deflect so that the sheet contacts the central region of said surface area but is spaced from said peripheral region;    means for effecting relative movement between the substrate and sheet until the sheet is in face-to-face planarizing contact with substantially all of said surface area; and    means for curing said surface coating while maintaining said planarizing contact.    
   
   
       15 . The apparatus of  claim 14 , wherein said apparatus does not include an optical flat body.