Photoresist, photolithography method using the same, and method for producing photoresist

Abstract

There is provided a positive photoresist for near-field exposure excellent in light utilization efficiency even with small layer thickness of the photoresist layer for image formation, and allowing for reduced pattern edge roughness, and a photolithography method including a step of exposing by the near-field exposure the photoresist layer for image formation made thereof. In a positive photoresist containing an alkali-soluble novolak resin and a quinone diazide compound, the film thickness of the photoresist at the time of exposure is not larger than 100 nm, and the absorption coefficient of the photoresist α (μm −1 ) for the exposure light is such that 0.5≦α≦7.

1 . A photoresist comprising an alkali-soluble novolak resin and a photosensitive compound having a naphthoquinone diazide group, wherein the absorption coefficient α (μm −1 ) of the photoresist for an exposure light falls in the range of 0.5≦α≦7.  
     
     
         2 . The photoresist as set forth in  claim 1 , wherein 30 to 150 parts by weight of the photosensitive compound per 100 parts by weight of the alkali-soluble novolak resin is contained.  
     
     
         3 . The photoresist as set forth in  claim 1 , wherein the average number of a photosensitive group in a molecule of the photosensitive compound is not smaller than 3.  
     
     
         4 . The photoresist as set forth in  claim 1 , wherein the GPC (gel permeation chromatograph) chart pattern area for the components of the alkali-soluble novolak resin having a molecular weight not smaller than 100,000 as reduced to the standard polystyrene is less than 1% of the total area.  
     
     
         5 . The photoresist as set forth in  claim 4 , wherein the weight-average molecular weight of the alkali-soluble novolak resin falls in the range of from 500 to 20,000.  
     
     
         6 . The photoresist as set forth in  claim 4 , wherein the molecular weight distribution (Mw/Mn) of the alkali-soluble novolak resin is not larger than 3.  
     
     
         7 . The photoresist as set forth in  claim 1 , wherein the photoresist contains Si.  
     
     
         8 .- 10 . (Cancelled)