EUV Success Stories

Example 1: Illumination system

In 2013, Rigaku completed a 5-optic illumination system, later linked to the 2016 delivery of a >400mm diameter collector. In addition to providing all multilayers, Rigaku was instrumental in the optical design analysis using such tools as Zemax, to optimize the optical scheme, optic shapes and multilayer designs.

The collector optic was a focusing ellipsoid of revolution, and had a surface grating that would reject unwanted infra-red (IR) radiation with minimal impact to the reflection of 13.5 nm EUV source. *Example 1, courtesy of “The Recent Study of Resist Outgassing in the Hydrogen Environment,” Eishi Shiobara et. al., 2016 International Symposium on Extreme Ultraviolet Lithography, International Sematech, Hiroshima, Japan, 2016.

The collector delivered the EUV light to a trio of paraboloid-shaped optics which created two separate beams of designed illumination, redirected via a pair of EUV 45° incidence flats.

Example 2: Illumination + imaging system

In 2012, Rigaku completed a multi-optic system for high-precision imaging. The first two optics were precision ellipsoid surfaces, with Rigaku-designed kinematic mounting systems, that delivered light into a Schwarzschild imaging system, a pair of aspherical optics. These illumination optics required complex 2-dimensional multilayer gradients to efficiently deliver EUV photons.

The imaging optics were deposited ultra-precisely with radial symmetry to minimize distortions to the near-perfect surface of the optics. Multilayer contributions to figure error were below 200 picometers. *Example 2, courtesty of “Defect Review Capability Enhancement for Actinic Blank Inspection Tool,” Kiwamu Takehisa et. al., 2016 International Symposium on Extreme Ultraviolet Lithography, International Sematech, Hiroshima, Japan, 2016.

Example 3: Illumination + imaging system

In 2005, Rigaku completed a multioptic Reticle Imaging System, that was composed of four illumination optics (C1-C4) and a pair of imaging optics (M1-M2). Precise and complex multilayer gradients were required to ensure uniform illumination, as well as ultra-low added distortions to the imaging field. *Example 3, image courtesy of private communications, reference material of 2006 EUVL Symposium, Proc. SPIE 6151, Emerging Lithographic Technologies X, (March 24, 2006)