Improved process compatibility through fill factor modulation

Abstract

The present invention provides a metrology target and a target design method in which target elements are defined by replacing elements from a periodic pattern with a pitch p with auxiliary elements to form a composite periodic structure maintaining said pitch p as a single pitch The element has at least one geometric difference from the replaced element. Constructing the target within the bounds of compatibility with advanced multi-patterning techniques improves the fidelity of the target, and fill factor modulation enables the target to be tuned to produce sufficient process compatibility to achieve the target. Simultaneously extract the metrological sensitivity of the overlay.

Description

[0001] Cross References to Related Applications [0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 318,086, filed April 4, 2016, which is hereby incorporated by reference in its entirety. technical field [0003] The present invention relates to the field of metrology, and more particularly, to overlay metrology target design. Background technique [0004] Overmetrology structures are faced with the need to meet the conflicting requirements of metrology sensitivity on the one hand and manufacturability or process compatibility on the other hand. Correspondingly, as an illustration, FIG. 1A presents schematically the trade-off between the sensitivity of the target design with respect to the segment size of the target structure and process compatibility according to the prior art. [0005] In general, the minimum pitch of the integration concept is significantly smaller than the so-called coarse pitch of a metering structure optimized ...

AI Technical Summary

Problems solved by technology

Large spacing 96 can affect target process compatibility, thus reducing target performance and device-target similarity

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