A Study of Flare Variation in Extreme Ultraviolet Lithography for Sub-22 nm Line and Space Pattern

One of the critical issues in extreme ultraviolet lithography (EUVL) is flare, which is an integrated light scattering from surface roughness in the EUVL optical system. Flare degrades the control of critical dimension (CD) uniformity across the exposure field. Also, it generates larger CD sensitivity as line and space (L/S) half pitch size decreases. Therefore, we discussed the calculation of accurate flare maps to compensate for flare variation. The influence of three-dimensional (3D) mask topography on flare was investigated with different absorber thicknesses, off-axis illumination angles, and azimuthal angles. Some types of dummy patterns were found to be effective in controlling the flare variation within a L/S patterned target and the average flare of a L/S patterned target. Our studies has definitely made progress in an effective flare variation compensation using a rule-based correction for sub-22 nm L/S half pitch node and beyond.

[1]  Joseph P. Kirk.  Scattered light in photolithographic lenses , 1994, Advanced Lithography.

[2]  P KirkJ.  Scattered light in photolithographic lenses. , 1994 .

[3]  Iwao Nishiyama,et al.  Impact of EUV light scatter on CD control as a result of mask density changes , 2002, SPIE Advanced Lithography.

[4]  Bryan J. Rice,et al.  Implementing flare compensation for EUV masks through localized mask CD resizing , 2003, SPIE Advanced Lithography.

[5]  Bryan J. Rice,et al.  Comparison of techniques to measure the point spread function due to scatter and flare in EUV lithography systems , 2004, SPIE Advanced Lithography.

[6]  M. Chandhok,et al.  Effects of flare in extreme ultraviolet lithography: Learning from the engineering test standa) , 2004 .

[7]  Bryan J. Rice,et al.  Determination of the flare specification and methods to meet the CD control requirements for the 32-nm node using EUVL , 2004, SPIE Advanced Lithography.

[8]  Franklin M. Schellenberg,et al.  Layout compensation for EUV flare , 2005, SPIE Advanced Lithography.

[9]  John Zimmerman,et al.  EUV lithography with the Alpha Demo Tools: status and challenges , 2007, SPIE Advanced Lithography.

[10]  Anne-Marie Goethals,et al.  Extreme ultraviolet lithography at IMEC: Shadowing compensation and flare mitigation strategy , 2007 .

[11]  J. Hartley,et al.  Initial experience establishing an EUV baseline lithography process for manufacturability assessment , 2007, SPIE Advanced Lithography.

[12]  Kurt G. Ronse,et al.  Full field EUV lithography turning into a reality at IMEC , 2007, Photomask Japan.

[13]  Gian Francesco Lorusso,et al.  EUV lithography program at IMEC , 2007, SPIE Advanced Lithography.

[14]  Lawrence S. Melvin,et al.  Flare mitigation strategies in extreme ultraviolet lithography , 2008 .

[15]  Anne-Marie Goethals,et al.  Experimental validation of full-field extreme ultraviolet lithography flare and shadowing corrections , 2008 .

[16]  N. Iriki,et al.  Flare-variation compensation for 32nm line and space pattern for device manufacturing on extreme-ultraviolet lithography , 2008 .

[17]  Chang-Moon Lim,et al.  Evaluation of shadowing and flare effect for EUV tool , 2009, Advanced Lithography.

[18]  Kazuo Tawarayama,et al.  Flare Impact and Correction for Critical Dimension Control with Full-Field Exposure Tool , 2009 .

[19]  Kevin Lucas,et al.  Requirements and results of a full-field EUV OPC flow , 2009, Advanced Lithography.