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Method of making photo-resist pattern by electron beam lithography with ionic liquid

IP.com Disclosure Number: IPCOM000237067D
Publication Date: 2014-May-29
Document File: 2 page(s) / 17K

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The IP.com Prior Art Database

Abstract

A method of making a photo-resist pattern by electron beam lithography using an ionic liquid is described.. This method is particularly useful in preventing an article from being electrostatically charged during electron beam lithography.

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Title:

Method of making photo-resist pattern by electron beam lithography with ionic liquid

Abstract

     A method of making a photo-resist pattern by electron beam lithography using an ionic liquid is described.. This method is particularly useful in preventing an article from being electrostatically charged during electron beam lithography.

Background Summary

     Photolithography is used in the manufacture of semiconductors, print wiring boards (print circuit board), liquid crystal display panels, plasma display panels and so on. A typical photolithographic process involves applying a photo-resist with a sensitivity to electron beam onto a base, exposing the photo-resist through a pattern mask, removing the exposed photo-resist and etching the now exposed base with a pattern transcribed from the mask..

     One problem with electron beam lithography is that the photo-resist can become electrostatically charged upon exposure to the electron beam. This electrostatic charging affects the trajectory of the electron beam causing it to lose focus. When the electron beam loses focus it is difficult to draw fine patterns on the photo-resist. We have discovered that applying an ionic liquid onto the photo-resist will dissipate the static charge and permit an accurate transcription of the pattern. We anticipate that adding an ionic liquid to the photo resist will also be effective.

     Ionic liquids with extremely low vapor pressure and high electrical conductivity are suitable for this method. Preferably the ionic liquid has a boiling point near room temperature and volatiles less than or 0.1%. Suitable cations for the ionic liquid include ammonium, imidazolium, pyridinium, pyrrolidinium, pyrazolium, phosphonium, and sulfonium. Suitable anions include Cl, Br, I, BF4, PF6, ClO4, NO3, CH3COO, CF3COO, CH3SO3, CF3SO3, C4F9SO3, (FSO2)2N, (CF3SO2)2N, (C2F5SO2)2N, (C3F7SO2)2N, (C4F9SO2)2N, (CF3SO2)3C. A preferred ionic liquid is FC-4400 (tri-n-butylmethylammonium bis-(trifluoromethanesulfonyl)imide available from 3M Company, St. Paul MN).

     Suitable...