Invention Grant
- Patent Title: System and method for focus control in extreme ultraviolet lithography systems using a focus-sensitive metrology target
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Application No.: US17143899Application Date: 2021-01-07
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Publication No.: US11460783B2Publication Date: 2022-10-04
- Inventor: Roel Gronheid , Xuemei Chen
- Applicant: KLA Corporation
- Applicant Address: US CA Milpitas
- Assignee: KLA Corporation
- Current Assignee: KLA Corporation
- Current Assignee Address: US CA Milpitas
- Agency: Suiter Swantz pc llo
- Main IPC: H01L21/027
- IPC: H01L21/027 ; G03F7/20

Abstract:
A focus-sensitive metrology target may be formed and read-out by a fabrication tool. A resulting overlay signal may be translated into a focus offset by comparison to a previously-determined calibration curve. One or more translated signals may be fed back to the fabrication tool for focus correction or used for prediction of on-device overlay (correction of overlay metrology results). In one embodiment, focus and overlay may be measured using a single target, where one portion of the target is formed on a first layer and includes a focus-sensitive design, and where another portion of the target is formed on a second layer and includes a relatively less focus-sensitive design. In some embodiments, a relative difference in focus response may be used to estimate an impact of focus error on device overlay and calculate non-zero offset contributions.
Public/Granted literature
Information query
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