Method and system for forming patterns with charged particle beam lithography

Abstract

In a method for fracturing or mask data preparation or mask process correction for charged particle beam lithography, a plurality of shots are determined that will form a pattern on a surface, where shots are determined so as to reduce sensitivity of the resulting pattern to changes in beam blur (β f ). In some embodiments, the sensitivity to changes in β f is reduced by varying the charged particle surface dosage for a portion of the pattern. Methods for forming patterns on a surface, and for manufacturing an integrated circuit are also disclosed, in which pattern sensitivity to changes in β f is reduced.

What is claimed is: 
     
         1 . A method for manufacturing a surface using a charged particle beam lithographic process comprising a beam blur (β f ), the method comprising:
 determining a plurality of charged particle beam shots that will form a pattern on the surface by producing a charged particle dosage on the surface, wherein the formed pattern comprises a perimeter, and wherein the determining is performed using one or more computing hardware processors; 
 reducing a sensitivity of the pattern to a variation in the β f ; and 
 forming the pattern on the surface with the plurality of shots. 
 
     
     
         2 . The method of  claim 1  wherein the pattern sensitivity to β f  is reduced by varying the charged particle surface dosage for a portion of the pattern. 
     
     
         3 . The method of  claim 1  wherein the sensitivity comprises critical dimension sensitivity. 
     
     
         4 . The method of  claim 1  wherein the reducing comprises using charged particle beam simulation. 
     
     
         5 . The method of  claim 4  wherein the charged particle beam simulation includes at least one of a group consisting of forward scattering, backward scattering, resist diffusion, Coulomb effect, etching, fogging, loading and resist charging. 
     
     
         6 . A method for manufacturing an integrated circuit using an optical lithographic process, the optical lithographic process using a reticle, wherein the reticle is manufactured using a charged particle beam lithographic process comprising a beam blur (β f ), the method comprising:
 determining a plurality of charged particle beam shots that will form a pattern on the surface by producing a charged particle dosage on the surface, wherein the formed pattern comprises a perimeter; 
 reducing a sensitivity of the pattern to a variation in the β f ; and 
 forming the pattern on the surface with the plurality of shots. 
 
     
     
         7 . The method of  claim 6  wherein the pattern sensitivity to β f  is reduced by varying the charged particle surface dosage for a portion of the pattern. 
     
     
         8 . The method of  claim 6  wherein the step of reducing comprises using charged particle beam simulation. 
     
     
         9 . The method of  claim 8  wherein the charged particle beam simulation includes at least one of a group consisting of forward scattering, backward scattering, resist diffusion, Coulomb effect, etching, fogging, loading and resist charging. 
     
     
         10 . A method for fracturing or mask data preparation or mask process correction for use with a charged particle beam lithographic process comprising a beam blur (β f ), the method comprising:
 determining a plurality of charged particle beam shots that will form a pattern on a surface by producing a charged particle dosage on the surface, wherein the formed pattern comprises a perimeter, and wherein the determining is performed using one or more computing hardware processors; and 
 reducing a sensitivity of the pattern to a variation in the β f . 
 
     
     
         11 . The method of  claim 10  wherein the pattern sensitivity to β f  is reduced by varying the charged particle surface dosage for a portion of the pattern. 
     
     
         12 . The method of  claim 11  wherein the varying comprises increasing the charged particle surface dosage in an area of the pattern near the perimeter of the pattern. 
     
     
         13 . The method of  claim 12  wherein the sensitivity comprises pattern area sensitivity of the pattern formed on the surface. 
     
     
         14 . The method of  claim 13  wherein the reducing comprises:
 simulating the pattern on the surface for a plurality of values of β f ; 
 increasing the area of increased surface dosage if the simulated pattern area decreases with increasing β f ; and 
 decreasing the area of increased surface dosage if the simulated pattern area increases with increasing β f . 
 
     
     
         15 . The method of  claim 10  wherein the sensitivity comprises critical dimension sensitivity. 
     
     
         16 . The method of  claim 10  wherein shots in the plurality of shots comprise multi-beam shots. 
     
     
         17 . The method of  claim 10  wherein shots in the plurality of shots comprises variable shaped beam (VSB) shots. 
     
     
         18 . The method of  claim 10  wherein some shots in the plurality of shots overlap each other, and wherein the pattern sensitivity to β f  is reduced by varying the overlap among shots in the plurality of shots. 
     
     
         19 . The method of  claim 10  wherein the reducing comprises using an optimization technique. 
     
     
         20 . The method of  claim 19  wherein the sensitivity is minimized or nearly minimized, within a pre-determined range of β f .