Method of forming a pattern of sub-micron broad features

Abstract

A pattern of very fine features ( 18 ) can be produced by illuminating an inorganic negative tone resist layer ( 16 ), provided on an electroplating base layer ( 14 ), by a beam (EB), which is able to cure the resist to a cured pattern according to the pattern to be formed, removing the non-illuminated portions of the resist layer and electroplating a layer ( 20 ) between the cured portions ( 18 ) of the resist layer.

1 . A method of forming a pattern of sub-micron broad features in a metal layer, which method includes the steps of: 
 forming a resist layer, comprising a negative tone resist material, on a substrate;    illuminating selected portions of the resist layer by a beam, which is able to cure the resist to a cured pattern according to the pattern to be formed, and    removing non-illuminated portions of the resist layer, which method is characterized in that the resist material is an inorganic material and in that the additional steps of: 
 forming an electroplating base layer on the substrate before applying the resist layer, and  
 electroplating a layer between the cured portions of the resist layer are carried out.  
   
     
     
         2 . A method as claimed in  claim 1 , characterized in that siloxane material is used as a resist material.  
     
     
         3 . A method as claimed in  claim 2 , characterized in that hydrogen silsesquioxane (HSQ) is used as a resist material.  
     
     
         4 . A method as claimed in  claim 1 ,  2 , or  3 , characterized in that a double layer comprising a hydrogen silsesquioxane top layer and a novolak bottom layer is used as a resist layer.  
     
     
         5 . A method as claimed in  claim 1 ,  2 ,  3  or  4 , characterized in that a layer of one of the materials: silver, nickel and permalloy is electroplated between the illuminated portions of the resist layer.  
     
     
         6 . A method as claimed in  claim 1 ,  2 ,  3 ,  4  or  5 , characterized in that a layer of one of the materials: silver, gold, copper, aluminum and molybdenum is used as an electroplating base layer.  
     
     
         7 . A method as claimed in any one of the preceding claims, characterized by the intermediate step of covering the substrate surface, which is to be provided with the pattern of features, with an insulating layer before the electroplating base layer is applied.  
     
     
         8 . A method as claimed in any one of the preceding claims, characterized by the additional step of removing the illuminated portions of the resist layer after finishing the electroplating process.  
     
     
         9 . A pattern of features manufactured by means of the method of any one of  claims 1  to  8 , characterized in that the features have a sub-micron width and are arranged at mutual distances which are substantially larger than the feature widths.  
     
     
         10 . A pattern of features manufactured by means of the method of any one of  claims 1  to  8 , forming a lithographic mask, wherein the pattern features constitute mask features which are transparent to lithographic projection radiation and the pattern areas between the features constitute mask areas which are non-transparent to lithographic projection radiation.  
     
     
         11 . A pattern of features manufactured by means of the method of any one of  claims 1  to  8 , forming a grating structure, wherein the pattern features constitute transparent grating strips and the pattern areas between the features constitute non-transparent intermediate strips.  
     
     
         12 . A pattern of features manufactured by means of the method of any one of  claims 1  to  8 , forming a structure of at least one magnetic gap in a thin-film magnetic recording head.