Improved CD control and line edge roughness in E-beam lithography through combining proximity effect correction with gray scale techniques

Jens Bolten, Thorsten Wahlbrink, Namil Koo, Heinrich Kurz, Stefan Stammberger, Uli Hofmann, Nezih Ünal
The 35th International Conference on Micro- and Nano-Engineering (MNE) 2009, Gent, Belgium


A proximity effect correction (PEC) technique for E-beam lithography is presented which overcomes hardware limitations of many older E-beam writers regarding the number of physical dose classes by a unique combination of gray scale techniques with PEC using the Layout BEAMER software. The benefit is not only an improvement in critical dimension control, but also an improvement in line edge roughness (LER). Compared to standard PEC techniques the percentage line width deviation has been dramatically reduced by more than a factor of three.


  • Electron beam lithography;
  • Proximity effect correction;
  • Line edge roughness;
  • Layout BEAMER

Figures and tables from this article:

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Fig. 1. 

Overview of test structure with corner and center region.

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Fig. 2a. 

SEM micrograph of the corner region exposed without PEC.

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Fig. 2b. 

SEM micrograph of the corner region exposed with an eight dose classes PEC.

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Fig. 2c. 

SEM micrograph of the corner region of a field exposed with a 32 dose classes PEC.

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Fig. 3. 

Critical dimension analysis for different PEC types. Values plotted represent mean values obtained by measurements of larger numbers of features.

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Fig. 4. 

Critical dimension analysis of imprint test structures. Again mean values are plotted.

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Supplementary material. 
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Supplementary material.