Acta Optica Sinica, Volume. 35, Issue 1, 122003(2015)
Effects and Improvements of Coating Induced Polarization Aberration on Lithography Lens Design
In order to achieve high imaging requirement of projection lithography lens, the impact of polarization effects induced by coatings need to be considered and analyzed during the design process.Polarization aberration theory based on the Jones matrix is first described, then the polarization aberration of a numerical aperture (NA) of 0.75 projection lithography lens with corresponding coating is analyzed as an example. The large power and spherical aberrations induced by the coating are compensated with space and focus optimization. The scalar aberration and point spread function distortion are improved from 68.92 nm and 3.76 nm to 1.08 nm and 0.38 nm, respectively. The contrast of 90 nm dense line also increases from 0.082 to 0.876. Based on this, a method to reduce polarization aberration introduced by coating is represented, such as retardation and diattenuation. Combined films are used to control the magnitude and phase separation of the P and S component simultaneously. With this method, the contrast of the 90nm dense line is improved by 1.1%.
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Shang Hongbo, Liu Chunlai, Zhang Wei, Chen Hua′nan. Effects and Improvements of Coating Induced Polarization Aberration on Lithography Lens Design[J]. Acta Optica Sinica, 2015, 35(1): 122003
Category: Optical Design and Fabrication
Received: May. 26, 2014
Accepted: --
Published Online: Dec. 18, 2014
The Author Email: Hongbo Shang (silverbirchs@gmail.com)