title: High-resolution subsurface microscopy of CMOS integrated circuits using radially polarized light.
abstract: Under high numerical aperture (NA) conditions, a linearly polarized plane wave focuses to a spot that is extended along the E-field vector, but radially polarized light is predicted to form a circular spot whose diameter equals the narrower dimension obtained with linear polarization. This effect provides an opportunity for improved resolution in high-NA microscopy, and here we present a performance study of subsurface two-photon optical-beam-induced current solid-immersion-lens microscopy of a complementary metal-oxide semiconductor integrated circuit, showing a resolution improvement by using radially polarized illumination. By comparing images of the same structural features we show that radial polarization achieves a resolution of 126 nm, while linear polarization achieves resolutions of 122 and 165 nm, depending on the E-field orientation. These results are consistent with the theoretically expected behavior and are supported by high-resolution images which show superior feature definition using radial polarization.
authors.forename: M
authors.initials: M
authors.lastname: Rutkauskas
authors.forename: C
authors.initials: C
authors.lastname: Farrell
authors.forename: C
authors.initials: C
authors.lastname: Dorrer
authors.forename: K L
authors.initials: KL
authors.lastname: Marshall
authors.forename: T R
authors.initials: TR
authors.lastname: Lundquist
authors.forename: P
authors.initials: P
authors.lastname: Vedagarbha
authors.forename: D T
authors.initials: DT
authors.lastname: Reid