Polarization-selective subwavelength grating used with 193 nm light

Hyper-NA ArF (193 nm) immersion lithography is one of the most potential technologies to achieve 32 nm critical dimension node. At the corresponding large angles in the photoresist, control of polarization becomes necessary. A polarization beam splitter (PBS) based on a subwavelength dielectric grating has been designed for use with 193 nm light. The polarization-selective property of such grating is explained by the mechanism of mode interference. The designed grating working as a 1 × 2 beam splitter can transmit TM wave (∼ 90%) to the zeroth order with extinction ratio of 753, and it diffracts TE wave (∼ 80%) to the −1st order with extinction ratio of 300.