Method for fabricating etch mask and patterning process using the same

Abstract

A method for fabricating a mask is provided. A patterned sacrificial layer is formed over a mask material layer, and the patterned sacrificial layer has an etch selectivity different from that of the mask material layer. An isotropic etch process is performed to the mask material layer by using the patterned sacrificial layer as an etch mask to form a mask layer, wherein the dimension of the mask layer is smaller than that of the patterned sacrificial layer.

1 . A method for fabricating a mask, comprising: 
 forming a patterned sacrificial layer over a mask material layer, the patterned sacrificial layer having an etch selectivity different from that of the mask material layer; and    performing an isotropic etch process to the mask material layer to form a mask layer by using the patterned sacrificial layer as an etch mask, a dimension of the mask layer being smaller than a dimension of the patterned sacrificial layer.    
   
   
       2 . The method for fabricating a mask of  claim 1 , wherein a method for forming the patterned sacrificial layer comprises: 
 forming a sacrificial layer over the mask material layer;    forming a patterned photoresist layer over the sacrificial layer; and    etching the sacrificial layer by using the patterned photoresist layer as an etch mask.    
   
   
       3 . The method for fabricating a mask of  claim 2 , wherein the patterned photoresist layer has a critical dimension (CD), and the dimension of the mask layer is smaller than a CD.  
   
   
       4 . The method for fabricating a mask of  claim 1 , wherein the isotropic etch process comprises a wet etch process.  
   
   
       5 . The method for fabricating a mask of  claim 1 , wherein the mask material layer comprises a material selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, polysilicon, doped polysilicon and a metal material.  
   
   
       6 . The method for fabricating a mask of  claim 1 , wherein the patterned sacrificial layer comprises a material selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, polysilicon, doped polysilicon and a metal material.  
   
   
       7 . A patterning process, comprising: 
 forming a mask material layer over a material layer, the mask material layer having an etch selectivity different from that of the material layer;    forming a patterned sacrificial layer over the mask material layer, the patterned sacrificial layer having an etch selectivity different from that of the mask material layer, the patterned sacrificial layer having an etch selectivity the same as, or different from, that of the material layer;    performing an isotropic etch process to the mask material layer to form a mask layer by using the patterned sacrificial layer as an etch mask, a dimension of the mask layer being smaller than a dimension of the patterned sacrificial layer; and    etching the material layer by using the mask layer as an etch mask.    
   
   
       8 . The patterning process of  claim 7 , wherein a method for forming the patterned sacrificial layer comprises: 
 forming a sacrificial layer over the mask material layer;    forming a patterned photoresist layer over the sacrificial layer; and    etching the sacrificial layer by using the patterned photoresist layer as an etch mask.    
   
   
       9 . The patterning process of  claim 8 , wherein the patterned photoresist layer has a critical dimension (CD), and the dimension of the mask layer is smaller than the CD.  
   
   
       10 . The patterning process of  claim 7 , wherein the isotropic etch process comprises a wet etch process.  
   
   
       11 . The patterning process of  claim 7 , wherein the mask material layer comprises a material selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, polysilicon, doped polysilicon and a metal material.  
   
   
       12 . The patterning process of  claim 7 , wherein the patterned sacrificial layer comprises a material selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, polysilicon, doped polysilicon and a metal material.  
   
   
       13 . The patterning process of  claim 7 , wherein the material layer comprises a material selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, polysilicon, doped polysilicon and a metal material.