縮小投影露光装置用合わせマークの高精度検出法(第2報) : 斜方照明・斜方検出法の性能と適用限界

概要

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The oblique illumination and oblique detection method, which detects the alignment mark at the exposure position without using through-the-lens technique is proposed, and its characteristics and application limits are analyzed. The alignment mark consists of the 6 μm-width and 5 μm-longitudinal pitch diffraction patterns. The illumination angle is 75°, and 60°-diffraction light is detected. The stable detection is realized by a 4-wavelength (458,488,515 and 543 nm) laser illumination, in which the variation of the detected signal is 24% in the range of 0.5-1.5 μm of pattern depth, 35% in the range of 0.7-2.7 μm of resist thickness, compared with the signal detected by the single wavelength light illumination. The experimental results give a detection repeatability of ±0.02 μm (3δ) in the range of 1.0-1.6μm of resist thickness and a detection error of ±0.03μm (3δ) in the range of (-3)-3 μm of focal error.
公益社団法人精密工学会の論文
1989-09-05