Thick film photoresists and methods for use thereof

Abstract

New methods and compositions are provided that enable application and processing of photoresist as thick coating layers, e.g. at dried layer (post soft-bake) thicknesses of in excess of 2 microns. Resists can be imaged at short wavelengths in accordance with the invention, including 248 nm.

1 . A method for providing a resist relief image comprising: 
 applying a liquid coating layer of a positive-acting photoresist on a substrate surface, the photoresist comprising a photoacid generator compound and a resin having photoacid-labile groups;    removing solvent from the photoresist coating layer to provide a layer thickness of at least about 1.5 microns;    exposing the photoresist coating layer to patterned activating radiation; heating the exposed photoresist coating layer to a temperature not exceeding about 115° C.; and    developing the photoresist coating layer to provide a resist relief image.    
     
     
         2 . The method of  claim 1  wherein the exposed photoresist relief image is heated at a temperature of about 105° C. or less after exposure.  
     
     
         3 . The method of  claim 1  wherein the exposed photoresist relief image is heated at about 100° C. or less after exposure.  
     
     
         4 . The method of  claim 1  wherein solvent is removed to provide a resist layer thickness of at least about 2 microns.  
     
     
         5 - 13 . (cancelled)  
     
     
         14 . The method of  claim 1  wherein the photoresist resin has an Mw molecular weight of about 20,000 or less.  
     
     
         15 . The method of  claim 1  wherein the photoresist composition comprises a diazomethanesulfone photoacid generator compound.  
     
     
         16 . The method of  claim 1  wherein the photoresist composition comprises an onium salt photoacid generator compound.  
     
     
         17 . The method of  claim 1  wherein the photoresist composition comprises a photoacid generator compound that generates a sulfonic acid upon exposure to activating radiation.  
     
     
         18 . The method of  claim 1  wherein the photoresist composition comprises a plasticizer compound.  
     
     
         19 . The method of  claim 18  wherein the plasticizer is a non-polymeric compound.  
     
     
         20 . The method of  claim 18  wherein the plasticizer is an aromatic compound.  
     
     
         21 . (cancelled)  
     
     
         22 . The method of  claim 1  wherein the photoresist coating layer is exposed to radiation having a wavelength of about 248 nm.  
     
     
         23 - 28 . (cancelled)  
     
     
         29 . A method for providing a resist relief image comprising: 
 applying a liquid coating layer of a positive-acting photoresist on a substrate surface, the photoresist comprising a photoacid generator compound and a resin having phenolic groups and polymerized alkyl acrylate groups that having photoacid-labile moieties;    removing solvent from the photoresist coating layer to provide a layer thickness of at least about 1.5 microns;    exposing the photoresist coating layer to patterned activating radiation;    heating the exposed photoresist coating layer to a temperature not exceeding about 120° C.; and    developing the photoresist coating layer to provide a resist relief image.    
     
     
         30 . The method of  claim 29  wherein the temperature differential between the maximum pre-exposure treatment temperature and the maximum post-exposure thermal treatment is from 10° C. to 30° C.  
     
     
         31 . (cancelled)  
     
     
         32 . A substrate having a positive-acting photoresist coating layer thereon, the photoresist comprising a photoacid generator compound and a resin having photoacid-labile groups, the coating layer having a thickness of at least about 1.5 microns and substantially free of resist solvent.  
     
     
         33 - 35 . (cancelled)  
     
     
         36 . The substrate of  claim 32  wherein the resist coating layer has a thickness of at least about 6 microns.  
     
     
         37 . The substrate of  claim 32  wherein the photoresist resin comprises phenolic units.  
     
     
         38 . The substrate of  claim 32  wherein the photoresist resin comprises phenolic and acrylate units.  
     
     
         39 . (cancelled)  
     
     
         40 . The substrate of  claim 32  wherein the photoresist resin has an Mw molecular weight of about 5,000 or less.  
     
     
         41 . The substrate of  claim 32  wherein the photoresist resin has a Tg of about 100° C. or less.  
     
     
         42 - 50 . (cancelled)