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Proceedings Paper

Particle detection for patterned wafers of 100nm design rule by evanescent light illumination: analysis of evanescent light scattering using finite-difference time-domain (FDTD) method
Author(s): Toshie Yoshioka; Takashi Miyoshi; Yasuhiro Takaya
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Paper Abstract

To realize high productivity and reliability of the semiconductor, patterned wafers inspection technology to maintain high yield becomes essential in modern semiconductor manufacturing processes. As circuit feature is scaled below 100nm, the conventional imaging and light scattering methods are impossible to apply to the patterned wafers inspection technique, because of diffraction limit and lower S/N ratio. So, we propose a new particle detection method using annular evanescent light illumination. In this method, a converging annular light used as a light source is incident on a micro-hemispherical lens. When the converging angle is larger than critical angle, annular evanescent light is generated under the bottom surface of the hemispherical lens. Evanescent light is localized near by the bottom surface and decays exponentially away from the bottom surface. So, the evanescent light selectively illuminates the particles on the patterned wafer surface, because it can't illuminate the patterned wafer surface. The proposed method evaluates particles on a patterned wafer surface by detecting scattered evanescent light distribution from particles. To analyze the fundamental characteristics of the proposed method, the computer simulation was performed using FDTD method. The simulation results show that the proposed method is effective for detecting 100nm size particle on patterned wafer of 100nm lines and spaces, particularly under the condition that the evanescent light illumination with p-polarization and parallel incident to the line orientation. Finally, the experiment results suggest that 220nm size particle on patterned wafer of about 200nm lines and spaces can be detected.

Paper Details

Date Published: 6 December 2005
PDF: 9 pages
Proc. SPIE 6049, Optomechatronic Sensors and Instrumentation, 604909 (6 December 2005); doi: 10.1117/12.647933
Show Author Affiliations
Toshie Yoshioka, Osaka Univ. (Japan)
Takashi Miyoshi, Osaka Univ. (Japan)
Yasuhiro Takaya, Osaka Univ. (Japan)


Published in SPIE Proceedings Vol. 6049:
Optomechatronic Sensors and Instrumentation
Yasuhiro Takaya, Editor(s)

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