Periodic patterns and technique to control misalignment between two layers
AssigneeKLA-Tencor Technologies Corporation
InventorsIbrahim Abdulhalim, Mike Adel, Michael Friedmann, Michael Faeyrman
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Abstract
A method and system to measure misalignment error between two overlying or interlaced periodic structures are proposed. The overlying or interlaced periodic structures are illuminated by incident radiation, and the diffracted radiation of the incident radiation by the overlying or interlaced periodic structures are detected to provide an output signal. The misalignment between the overlying or interlaced periodic structures may then be determined from the output signal.
Claims34
A method for detecting misalignment of overlying or interlaced periodic structures, comprising:
- illuminating the overlying or interlaced periodic structures with incident radiation;
- detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures to provide an output signal;
- and
- determining a misalignment between the structures from the output signal, wherein effects of diffraction of said incident radiation by said periodic structures are accounted for in the determining, wherein the diffracted radiation detected comprises positive first-order diffraction and negative first-order diffraction.
An apparatus for detecting misalignment of overlying or interlaced periodic structures, comprising:
- a source illuminating the overlying or interlaced periodic structures with incident radiation;
- at least one detector detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures to provide an output signal;
- and
- a processor determining a misalignment between the structures from the output signal, wherein effects of diffraction of said incident radiation by said periodic structures are accounted for in the determining, wherein the diffracted radiation detected comprises positive first-order diffraction and negative first-order diffraction.
Dependencies are inferred from the claim text.