New-generation projection optics for microlithography

Abstract

In order to meet the requirements ofthe Semiconductor industry, Canon has developed two new optical systems. First is an extension of KrF technology, with the introduction of high NAO.73 lens for KrF scanner that will cover the 130 nm device node. Second is the O.57NA optics for wide field (30 mm square) i-line stepper, to be used cost-effectively on Mix & Match modes. These new generation lenses behave very low aberration. Wavefront is accurately measured by PM! (Phase Measurement Interferometer). At each tuning process, many image performance items are estimated by simulations, and then the results feed back to tuning. Further, not only we make Wavefront RMS minimum, but also each Zernike coefficients are balanced for the various pattern models. So the lens may perform to the level of the industry 's requirement. This paper reports the imaging performance; simulation result calculated with final PM! data, and exposed image performance, ofthe above two new generation optics.