Method for fabricating fine pattern in semiconductor device

Abstract

A method for fabricating a fine pattern in a semiconductor device includes forming a first photoresist over a substrate where an etch target layer is formed, doping at least one impurity selected from group III elements and group V elements, of the periodic table, into the first photoresist, forming a photoresist pattern over the first photoresist, performing a dry etching process using the photoresist pattern to expose the first photoresist, etching the first photoresist by an oxygen-based dry etching to form a first photoresist pattern where a doped region is oxidized, and etching the etch target layer using the first photoresist pattern as an etch barrier.

1 . A method for fabricating a fine pattern in a semiconductor device, the method comprising:
 forming a first photoresist over a substrate where an etch target layer is formed;   doping one impurity selected from group III and group V elements into the first photoresist;   performing an oxidation process to oxidize a doped region of the photoresist;   forming a photoresist pattern over the first photoresist;   patterning the first photoresist using the photoresist pattern as an etch barrier; and   etching the etch target layer using the first photoresist pattern, where the doped region is oxidized, as an etch barrier.   
     
     
         2 . The method of  claim 1 , wherein the forming of the photoresist pattern comprises:
 forming a bottom anti-reflective coating over the first photoresist;   forming a second photoresist over the bottom anti-reflective coating; and   performing an exposure process and a development process on the second photoresist.   
     
     
         3 . The method of  claim 1 , wherein the impurity is selected from the group consisting of boron (B), indium (In), phosphorus (P), and arsenic (As). 
     
     
         4 . The method of  claim 1 , wherein the impurity is doped by an ion implantation process. 
     
     
         5 . The method of  claim 1 , wherein the impurity is doped by a plasma doping process. 
     
     
         6 . The method of  claim 4 , wherein the doping of the impurity comprises performing an annealing process for diffusing the impurity doped by the ion implantation process. 
     
     
         7 . The method of  claim 1 , wherein the oxidation process comprises an oxygen plasma process or an annealing process under an oxygen atmosphere. 
     
     
         8 . The method of  claim 1 , wherein the etch target layer comprises a silicon oxide layer or a silicon nitride layer. 
     
     
         9 . The method of  claim 2 , wherein the patterning of the first photoresist comprises:
 etching the exposed bottom anti-reflective coating and the doped region of the first photoresist by using a fluorine (F) containing gas and the photoresist pattern as an etch barrier; and   removing the photoresist pattern by a photoresist removal process, and patterning the first photoresist.   
     
     
         10 . The method of  claim 9 , wherein the photoresist removal process comprises an oxygen-based dry etching process.