12 October 2017 Influence of a wrinkle in terms of critical dimension variation caused by transmission nonuniformity and a particle defect on extreme ultraviolet pellicle
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J. of Micro/Nanolithography, MEMS, and MOEMS, 16(4), 041008 (2017). doi:10.1117/1.JMM.16.4.041008
Abstract
An extreme ultraviolet (EUV) pellicle is needed for the protection of EUV masks from defects, contaminants, and particles during the exposure process. However, the EUV pellicle can be easily deformed during the exposure process because it has an extremely thin thickness for high transmission of EUV lights. Due to the very thin thickness and the weak structure of the pellicle, a pellicle is easily deformed; a wrinkled pellicle causes an image distortion, which leads to critical dimension (CD) variation. In addition, a particle defect on an EUV pellicle can result from scanner building materials. Added materials of the particle defect on an EUV pellicle can also cause image distortion and CD variation. We investigated the impact of wrinkles and particle defects on the transmission and CD variation for the 5- and 3-nm nodes of isomorphic and anamorphic numerical aperture (NA) systems. The variation in transmission and the critical size of the particle defect with a wrinkled EUV pellicle were calculated to obtain the requirement of a CD variation of 0.2 nm for a EUV pellicle. As a result, a change in transmission of 1.9% (after two pass) resulted in a 0.2-nm variation in the CD for the anamorphic NA system (3-nm node), whereas a transmission variation of 1.3% (after two pass) caused a 0.2-nm CD variation in the isomorphic NA system (5-nm node). From these results, an allowable local tilt angle can be calculated; the allowable local tilt angle of an isomorphic NA system is 0.31 rad and that of an anamorphic NA system is 0.41 rad. When the particle defect is added on a wrinkled EUV pellicle, the critical size of the particle defect is 1.2    μ m for the 5-nm node and 2.2    μ m for the 3-nm node.
© 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Guk-Jin Kim, In-Seon Kim, Sung-Gyu Lee, Michael Yeung, Min-Su Kim, Jin-Goo Park, Hye-Keun Oh, "Influence of a wrinkle in terms of critical dimension variation caused by transmission nonuniformity and a particle defect on extreme ultraviolet pellicle," Journal of Micro/Nanolithography, MEMS, and MOEMS 16(4), 041008 (12 October 2017). http://dx.doi.org/10.1117/1.JMM.16.4.041008 Submission: Received 27 April 2017; Accepted 21 September 2017
Submission: Received 27 April 2017; Accepted 21 September 2017
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KEYWORDS
Pellicles

Particles

Extreme ultraviolet

Critical dimension metrology

Extreme ultraviolet lithography

Photomasks

Chromium

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