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Metrology method, target and substrate

  • US 10,386,176 B2
  • Filed: 08/25/2015
  • Issued: 08/20/2019
  • Est. Priority Date: 08/29/2014
  • Status: Active Grant
First Claim
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1. A method comprising:

  • illuminating with a measurement spot of radiation a diffraction measurement target on a substrate to produce diffracted radiation having one or more diffraction orders, the measurement target comprising at least a first sub-target, a second sub-target and a third sub-target, wherein the first, second and third sub-targets are different in design, wherein one or more selected from the first sub-target, second sub-target or third sub-target has a target structure in a first layer at least partially overlapping a target structure in a second layer, wherein each of the first to third sub-targets is designed for a different set of process stack conditions for the substrate or is designed for a different layer-pair among three or more layers for overlay measurement, and wherein the beam spot is sized so as to cover at one time at least part of each of a periodic structure of the first to third sub-targets.

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