Optical Scanner Tool Matching Using Zernike Aberration Maps

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Solution Overview

Problem

Matching scanner tools in a production line to produce consistent critical dimensions (CD) without designating a single 'golden' scanner tool, which can be costly, is challenging.

Innovation Solution

Adjusting Zernike coefficients to align aberration maps of scanner tools by modifying the location and curvature of mirrors and lenses, using a controller to optimize CD uniformity across multiple tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a golden scanner tool is designated as reference for matching, then manufacturing precision of CD is improved, but device complexity and cost increase

Engineering Contradiction:

Improvecritical dimension consistencyVSAvoidreference tool designation

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses wavefront sensor measurements to create a digital copy or representation of the optical aberrations in each scanner tool. By measuring and storing the aberration characteristics of each tool individually, the system creates a reference model for each tool without requiring a physical golden scanner tool, thereby reducing complexity while maintaining precision

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent changes the approach from designating a golden tool to measuring and adjusting optical parameters (wavefront aberrations) of each individual tool. By using wavefront sensors to measure and quantify the optical parameters of each scanner, the system enables precise matching through parameter adjustment rather than reference to a golden tool

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If wavefront sensor measurement is used to determine aberration map, then manufacturing precision is improved, but measurement complexity increases

Engineering Contradiction:

Improveaberration map accuracyVSAvoidwavefront measurement

Core Design Contradiction:

Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces a wavefront sensor as an intermediary device that indirectly measures the optical aberrations by detecting wavefront distortions. Instead of directly measuring complex aberration maps, the system uses the wavefront sensor as a mediator to convert difficult-to-measure optical properties into measurable wavefront data, simplifying the measurement process while maintaining accuracy

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces complex mechanical alignment and direct aberration measurement methods with optical wavefront sensing. By using optical interference and wavefront detection techniques instead of mechanical measurement approaches, the system achieves higher precision with reduced measurement complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20250321498A1Tool mismatch reduction using aberration map of the tools

Publication Date: 2025.10.16 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

In a method of tool matching, aberration maps of two or more optical systems of two or more scanner tools are determined. A photoresist pattern is generated by projecting a first layout pattern by an optical system of each one of the two or more scanner tools on a respective substrate. One or more Zernike coefficients of the two or more optical systems are adjusted based on the determined aberration maps of the two or more optical systems to minimize critical dimension (CD) variations in a first region of the photoresist patterns on each respective substrate.