22 August 2001 Using pattern quality confirmation to control a metal-level DUV process with a top-down CD-SEM
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Abstract
As critical-feature patterning processes increase in complexity and sensitivity, conventional critical dimension (CD) measurements may not afford the level of process control required for effective device production. By comparing recorded top-down scanning-electron-microscope (SEM) images to a predefined reference image, Pattern Quality Confirmation (pQC) enables a more detailed analysis of measurements captured by KLA-Tencor 8XXX series scanning-electron microscopes. An example of the utility of this additional information is discussed below for a metal interconnect level patterned with a conventional deep-ultraviolet (DUV) photolithography process. In particular, we demonstrate that for certain ranges of focus-exposure conditions, conventional post-develop CD measurements remain well within specification, however, when etched, the resulting metal-line CDs are significantly below the lower specification limit. The pQC image analysis results, however, predict the observed post-etch CD variations, and consequently offer sensitivity to yield-limiting focus drifts and excursions, enabling effective product-dispositioning (rework) decisions.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Chien-Sung Liang, Haiqing Zhou, Mark A. Boehm, Ricky A. Jackson, Chih-Yu Wang, Michael D. Slessor, "Using pattern quality confirmation to control a metal-level DUV process with a top-down CD-SEM", Proc. SPIE 4344, Metrology, Inspection, and Process Control for Microlithography XV, (22 August 2001); doi: 10.1117/12.436727; https://doi.org/10.1117/12.436727
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