Paper
22 March 2016 Holistic, model-based optimization of edge leveling as an enabler for lithographic focus control: application to a memory use case
T. Hasan, Y.-S. Kang, Y.-J. Kim, S.-J. Park, S.-Y. Jang, K.-Y. Hu, E. J. Koop, P. C. Hinnen, M. M. A. J. Voncken
Author Affiliations +
Abstract
Advancement of the next generation technology nodes and emerging memory devices demand tighter lithographic focus control. Although the leveling performance of the latest-generation scanners is state of the art, challenges remain at the wafer edge due to large process variations. There are several customer configurable leveling control options available in ASML scanners, some of which are application specific in their scope of leveling improvement. In this paper, we assess the usability of leveling non-correctable error models to identify yield limiting edge dies. We introduce a novel dies-inspec based holistic methodology for leveling optimization to guide tool users in selecting an optimal configuration of leveling options. Significant focus gain, and consequently yield gain, can be achieved with this integrated approach. The Samsung site in Hwaseong observed an improved edge focus performance in a production of a mid-end memory product layer running on an ASML NXT 1960 system. 50% improvement in focus and a 1.5%p gain in edge yield were measured with the optimized configurations.
© (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
T. Hasan, Y.-S. Kang, Y.-J. Kim, S.-J. Park, S.-Y. Jang, K.-Y. Hu, E. J. Koop, P. C. Hinnen, and M. M. A. J. Voncken "Holistic, model-based optimization of edge leveling as an enabler for lithographic focus control: application to a memory use case", Proc. SPIE 9778, Metrology, Inspection, and Process Control for Microlithography XXX, 97783G (22 March 2016); https://doi.org/10.1117/12.2219121
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KEYWORDS
Semiconducting wafers

Scanners

Servomechanisms

Sensors

Optimization (mathematics)

Lithography

Yield improvement

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