Method of patterning an anti-reflective coating by partial etching

Abstract

A method of patterning a thin film is described. The method comprises forming a thin film to be patterned on a substrate, forming an anti-reflective coating (ARC) layer on the thin film, and forming a mask layer on the ARC layer. Thereafter, the mask layer is patterned to form a pattern therein, and the pattern is partially transferred to the ARC layer using a transfer process, such as an etching process. Once the mask layer is removed, the pattern is completely transferred to the ARC layer using an etching process, and the pattern in the ARC layer is transferred to the underlying thin film using another etching process.

1 . A method of patterning a thin film on a substrate, comprising:
 preparing a film stack on said substrate, said film stack comprising said thin film formed on said substrate, an anti-reflective coating (ARC) layer formed on said thin film, and a mask layer formed on said ARC layer;   forming a pattern in said mask layer;   partially transferring said pattern to said ARC layer by transferring said pattern to a depth less than the thickness of said ARC layer;   removing a remainder of said mask layer following said partial transfer of said pattern to said ARC layer;   completing said transferring of said pattern to said ARC layer by etching said ARC layer; and   transferring said pattern to said thin film while substantially consuming said ARC layer.   
   
   
       2 . The method of  claim 1 , wherein said forming a pattern in said mask layer comprises forming a pattern in a layer of photo-resist. 
   
   
       3 . The method of  claim 2 , wherein said forming a pattern in said mask layer comprises:
 imaging said layer of photo-resist with an image pattern using a photo-lithography system; and   developing said layer of photo-resist in order to form said image pattern in said layer of photo-resist.   
   
   
       4 . The method of  claim 1 , wherein said partially transferring said pattern to said ARC layer comprises performing at least one of dry etching, or wet etching, or a combination thereof. 
   
   
       5 . The method of  claim 4 , wherein said partially transferring said pattern to said ARC layer comprises performing dry plasma etching, dry non-plasma etching, or a combination thereof. 
   
   
       6 . The method of  claim 4 , wherein said partially transferring said pattern to said ARC layer comprises performing an anisotropic dry etching process, a reactive ion etching process, a laser-assisted etching process, an ion milling process, or an imprinting process, or a combination of two or more thereof. 
   
   
       7 . The method of  claim 1 , wherein said completing said transferring of said pattern to said ARC layer comprises performing a wet etching process, or a dry etching process, or a combination thereof. 
   
   
       8 . The method of  claim 1 , wherein said forming said mask layer comprises forming a 248 nm resist, a 193 nm resist, a 157 nm resist, or an EUV resist, or a combination of two or more thereof on said ARC layer. 
   
   
       9 . The method of  claim 1 , wherein said forming said film stack further comprises forming an organic planarization layer (OPL) on said thin film and forming said ARC layer on said OPL. 
   
   
       10 . The method of  claim 9 , wherein said forming said OPL comprises forming a polyacrylate resin, an epoxy resin, a phenol resin, a polyamide resin, a polyimide resin, an unsaturated polyester resin, a polyphenylenether resin, a polyphenylenesulfide resin, or benzocyclobutene (BCB), or a combination of two or more thereof. 
   
   
       11 . The method of  claim 9 , further comprising:
 transferring said pattern in said ARC layer to said OPL prior to said transferring said pattern to said thin film.   
   
   
       12 . The method of  claim 11 , wherein said transferring said pattern in said ARC layer to said OPL comprises etching said pattern into said OPL. 
   
   
       13 . The method of  claim 9 , further comprising:
 removing said OPL following said transferring said pattern to said thin film.   
   
   
       14 . The method of  claim 9 , wherein said transferring said pattern in said ARC layer to said OPL substantially consumes said ARC layer. 
   
   
       15 . The method of  claim 1 , wherein said forming said ARC layer comprises forming an organic layer, an inorganic layer, or both. 
   
   
       16 . A computer readable medium containing program instructions for execution on a control system, which when executed by the control system, cause a patterning system to perform the steps of:
 preparing a film stack on a substrate, said film stack comprising a thin film formed on said substrate, an anti-reflective coating (ARC) layer formed on said thin film, and a mask layer formed on said ARC layer;   forming a pattern in said mask layer;   partially transferring said pattern to said ARC layer by transferring said pattern to a depth less than the thickness of said ARC layer;   removing a remainder of said mask layer following said partial transfer of said pattern to said ARC layer;   completing said transferring of said pattern to said ARC layer by etching said ARC layer; and   transferring said pattern to said thin film while substantially consuming said ARC layer.