Determining focus positions for imaging a substrate with an integrated

Through the integration of photon sensors and a metamorphic grating coupler, the equipment bulky and expensive problem of determining the focus position of the substrate imaging in lithographic projection devices is solved, achieving more efficient focus measurement.

CN120266057APending Publication Date: 2025-07-04ASML NETHERLANDS BV
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Patent Information

Application Number
CN202380084359.9
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Priority Date
2022-12-09
Filing Date
2023-11-14
Publication Date
2025-07-04

AI Technical Summary

Technical Problem

In existing lithographic projection devices, determining the focus position of the substrate imaging requires separate focus branches, resulting in the device being bulky and expensive, and having phase difference problems in optical device design.

Method used

Using an integrated photon sensor, a variable grating coupler is used to design the amplitude and phase of the grating coupler mode to determine the optimal coupling efficiency, and the focus position is determined based on the coupling efficiency and known positions by changing the grating period and duty cycle.

Benefits of technology

Reduces the physical volume and cost of the device, avoids potential problems with optical device design in existing methods, and provides continuous focused measurement capabilities.

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Abstract

The metrology system (s) and method (s) described herein eliminate the need for separate focus branches commonly used in existing metrology systems to determine focus positions for imaging a substrate. The focus position is determined using an integrated photon sensor instead of using a separate focus branch. The integrated photon sensor is based on apodized grating couplers in which the amplitude and phase of the grating coupler mode are designed to have optimal coupling efficiency for a particular defocus (or initial / known focus position) by varying the grating period and / or duty cycle. A coupling efficiency between the emission grating and the reception grating is determined based on emitted radiation and reflected radiation received from the substrate, the emitted radiation having a particular amplitude and a particular phase configured for a known position relative to the substrate. A focus position is determined based on the coupling efficiency and the known position.
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