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Proceedings Paper

SAQP pitch walk metrology using single target metrology
Author(s): Fang Fang; Pedro Herrera; Taher Kagalwala; Janay Camp; Alok Vaid; Stilian Pandev; Franz Zach
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Paper Abstract

Self-aligned quadruple patterning (SAQP) processes have found widespread acceptance in advanced technology nodes to drive device scaling beyond the resolution limitations of immersion scanners. Of the four spaces generated in this process from one lithography pattern two tend to be equivalent as they are derived from the first spacer deposition. The three independent spaces are commonly labelled as α, β and γ. α, β and γ are controlled by multiple process steps including the initial lithographic patterning process, the two mandrel and spacer etches as well as the two spacer depositions. Scatterometry has been the preferred metrology approach, however is restricted to repetitive arrays. In these arrays independent measurements, in particular of alpha and gamma, are not possible due to degeneracy of the standard array targets. . In this work we present a single target approach which lifts the degeneracies commonly encountered while using product relevant layout geometries. We will first describe the metrology approach which includes the previously described SRM (signal response metrology) combined with reference data derived from CD SEM data. The performance of the methodology is shown in figures 1-3. In these figures the optically determined values for alpha, beta and gamma are compared to the CD SEM reference data. The variations are achieved using controlled process experiments varying Mandrel CD and Spacer deposition thicknesses.

Paper Details

Date Published: 28 March 2017
PDF: 7 pages
Proc. SPIE 10145, Metrology, Inspection, and Process Control for Microlithography XXXI, 101452R (28 March 2017); doi: 10.1117/12.2261620
Show Author Affiliations
Fang Fang, GLOBALFOUNDRIES Inc. (United States)
Pedro Herrera, KLA-Tencor Corp. (United States)
Taher Kagalwala, GLOBALFOUNDRIES Inc. (United States)
Janay Camp, KLA-Tencor Corp. (United States)
Alok Vaid, GLOBALFOUNDRIES Inc. (United States)
Stilian Pandev, KLA-Tencor Corp. (United States)
Franz Zach, KLA-Tencor Corp. (United States)

Published in SPIE Proceedings Vol. 10145:
Metrology, Inspection, and Process Control for Microlithography XXXI
Martha I. Sanchez, Editor(s)

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