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Proceedings Paper

Quantitative line edge roughness characterization for sub-0.25-um DUV lithography
Author(s): Avinash Kant; George Talor; Nandasiri Samarakone
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Paper Abstract

As gate dimensions continue to shrink, improving CD control is a major challenge for sub-0.25 micron DUV lithography. One concern is line edge roughness which takes the form of both high and low frequency effects. In this paper, high frequency line edge roughness refers to high frequency small amplitude CD variations noted along the edge of a wet developed resist feature. Low frequency line edge roughness (LFLER) refers to the higher amplitude waviness observed along the edge of developed features. BOth these roughness parameters could lead to significant variations in device characteristics. Several factor such as the resist formation, quality of the aerial image and process conditions have in the past been attributed as possible sources of roughness. In this study, a quantitative characterization of wet developed feature roughness was conducted and attempts were made to determine the sources of its origin, along with the impact of plasma etch. High and low frequency LER was characterized using a Dektak SXM atomic force microscope and a Hitachi 7800 scanning electron microscope. Nominal 0.20, 0.18, and 0.16 micrometers isolated lines were studied following photolithography and the gate etch. Additional variables in this study included substrate type, resists composition, develop time, focus and the impact of aerial image.

Paper Details

Date Published: 14 June 1999
PDF: 8 pages
Proc. SPIE 3677, Metrology, Inspection, and Process Control for Microlithography XIII, (14 June 1999); doi: 10.1117/12.350833
Show Author Affiliations
Avinash Kant, Rockwell Semiconductor Systems (United States)
George Talor, Rockwell Semiconductor Systems (United States)
Nandasiri Samarakone, Conexant Systems Inc. (United States)


Published in SPIE Proceedings Vol. 3677:
Metrology, Inspection, and Process Control for Microlithography XIII
Bhanwar Singh, Editor(s)

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