Controlling resist profiles through substrate modification

Abstract

Photoresists may be formed over a structure that has been modified so as to poison a lower layer of the photoresist. Then, when the photoresist is patterned, it is only patterned down to the poisoned layer. The poisoned layer may be removed subsequently. However, because of the use of the modification process, the critical dimensions of the photoresist may be improved in some embodiments.

1 . A semiconductor element comprising: 
 a structure; and    a photoresist on said structure, said structure including a chemical to interfere with the ability of said photoresist to be altered by radiation exposure.    
   
   
       2 . The element of  claim 1  including a chemical that neutralizes a chemical in said photoresist that alters the photoresist upon radiation exposure.  
   
   
       3 . The element of claim l wherein said substance is a proton donor generator.  
   
   
       4 . The element of  claim 3  wherein said photoresist uses a proton acceptor generator to enable the photoresist to be altered by radiation exposure.  
   
   
       5 . The element of  claim 4  wherein said substance is a photo-acid generator.  
   
   
       6 . The element of  claim 4  wherein said substance is a thermal acid generator.  
   
   
       7 . The element of  claim 1  wherein said substance is a proton acceptor generator.  
   
   
       8 . The element of  claim 7  wherein said photoresist uses a proton donor generator to enable the photoresist to be altered by radiation exposure.  
   
   
       9 . The element of  claim 8  wherein said substance is a photo-base generator.  
   
   
       10 . The element of  claim 8  wherein said substance is a thermal base generator.  
   
   
       11 . The element of  claim 1  wherein said substance generates a proton or a proton acceptor upon exposure to a predetermined ambient condition.  
   
   
       12 . A method comprising: 
 providing a structure to promote the alteration, upon exposure to radiation, of a portion of an overlying photoresist layer; and    forming photoresist over said structure.    
   
   
       13 . The method of  claim 12  including promoting alteration of a region of the photoresist by modifying the structure so that the portion of the photoresist adjacent said structure is entirely subject to patterning in the exposed areas.  
   
   
       14 . The method of  claim 12  wherein providing a structure to promote includes providing a compound in said structure to compliment acid-base reactions within the photoresist.  
   
   
       15 . The method of  claim 14  including promoting the decomposition of the photoresist by increasing the concentration of the substance in said portion that enables the photoresist to be altered when exposed to radiation.  
   
   
       16 . The method of  claim 15  including promoting the decomposition of the photoresist in a layer proximate to said structure.  
   
   
       17 . The method of  claim 12  wherein providing a structure includes providing a liftoff layer.  
   
   
       18 . The method of  claim 12  wherein providing a structure includes providing a resist release layer.  
   
   
       19 . The method of  claim 12  including forming a trench through the photoresist down to the substrate using radiation exposure and subsequently removing said portion.  
   
   
       20 . The method of  claim 12  wherein, if the photoresist uses a photo-acid generator to alter the photoresist upon exposure, providing additional photo-acid generator in said structure.  
   
   
       21 . The method of  claim 12  wherein providing a structure includes providing a substance in said structure that promotes the decomposition of an overlying portion of said photoresist layer.  
   
   
       22 . The method of  claim 21  including providing a proton acceptor that compliments the action of a photo active proton acceptor to decompose the photoresist.  
   
   
       23 . The method of  claim 21  including providing a proton donor in said structure that compliments the action of a proton donor in said photoresist to decompose the photoresist.  
   
   
       24 . The method of  claim 12  including providing a layer beneath the photoresist, said layer including a substance to increase the ability of said photoresist to be altered by radiation exposure, and baking said layer to cause said substance to enter the photoresist.