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Publication Citation: Shape-Sensitive Linewidth Measurements of Resist Structures

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Author(s): John S. Villarrubia; Andras Vladar; Michael T. Postek;
Title: Shape-Sensitive Linewidth Measurements of Resist Structures
Published: January 01, 2004
Abstract: Widths of developed 193 nm resist lines were measured by two methods and compared. One method was a new model-based library method. In this method the scanning electron microscope (SEM) images corresponding to various edge shapes are simulated in advance, and the measured images are compared to the simulated ones to find the best match. For the second measurement the lines were cross-sectioned and imaged in the SEM. Similar studies have been previously performed for polycrystalline silicon lines, but this is the first such comparison for resist, a material for which additional measurement issues related to charging and/or shrinkage under electron beam exposure are widely anticipated. Comparisons were made for 48 different image targets, each of which contained 3, 5, or 10 lines depending upon whether that targets linewidths were nominally 350 nm, 200 nm, or 100 nm respectively. The average difference between the two methods was 3.5 nm. Individual measurements deviated from this average value with a standard deviation of approximately 5 nm, of which 3 nm could be attributed to roughness of the lines edges. The effect on linewidth metrology of the resists charging or shrinkage for these samples were at most a few nanometers. (12 references)
Citation: NIST Interagency/Internal Report (NISTIR) - 7089
Pages: pp. 1 - 26
Keywords: 193 nm resist,linewidth metrology,model-based library,scanning electron microscopy (SEM),simulation
Research Areas: Metrology, Manufacturing