Metrology Fleet Error Compensation Using ML Matching Signals

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Solution Overview

Problem

Current metrology systems face challenges in maintaining measurement consistency across multiple tools and applications, particularly in semiconductor manufacturing, due to systematic errors and the need for frequent recalibration, which can lead to reduced yield and increased costs.

Innovation Solution

A machine learning-based error evaluation model is trained using composite measurement matching signals to optimize system parameters across a fleet of metrology tools, reducing computational effort and enabling rapid systematic error monitoring and optimization, thus improving tool-to-tool matching and measurement stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional calibration approaches are used to maintain measurement consistency across multiple metrology systems, then measurement precision is improved, but device complexity and time consumption increase due to frequent recalibration requirements

Engineering Contradiction:
Improvemeasurement consistencyVSAvoidrecalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-training a machine learning model using composite measurement matching signals from multiple metrology systems. This pre-trained model captures systematic errors and relationships between systems in advance, enabling rapid error compensation during operation without requiring frequent recalibration. The model is trained offline using historical measurement data, and then deployed for real-time correction, thus performing the calibration work beforehand rather than repeatedly during operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the traditional mechanical calibration process with a computational machine learning approach. Instead of physically adjusting and recalibrating metrology systems through manual or automated mechanical procedures, the system uses a trained ML model to computationally compensate for systematic errors. This substitution transforms a time-consuming physical process into a rapid computational operation, significantly reducing recalibration time while maintaining measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If traditional calibration approaches are used to maintain measurement consistency across multiple metrology systems, then measurement precision is improved, but device complexity increases due to multiple calibration procedures

Engineering Contradiction:
Improvemeasurement consistencyVSAvoidcalibration procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple calibration procedures into a single unified machine learning model. Instead of applying separate calibration procedures to each metrology system individually, the system combines measurement data from multiple systems to train a comprehensive ML model that captures inter-system relationships. This single model then provides coordinated error compensation across all systems, replacing multiple complex calibration procedures with one unified computational approach.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal calibration solution through a multi-functional machine learning model that can compensate for systematic errors across different types of metrology systems and various measurement applications. The single trained model serves multiple functions: it corrects errors in different measurement modalities, adapts to various target structures, and maintains consistency across the entire metrology fleet. This universal approach eliminates the need for separate calibration procedures for each system type or application.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If frequent recalibration is performed to maintain measurement stability, then measurement precision is improved, but productivity decreases due to reduced manufacturing throughput

Engineering Contradiction:
Improvemeasurement stabilityVSAvoidmanufacturing throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent performs calibration work in advance by training the machine learning model offline using historical measurement data. Once trained, the model can rapidly compensate for systematic errors during production without interrupting the manufacturing flow. This shifts the time investment from the production phase to the preparation phase, allowing frequent error correction without sacrificing manufacturing throughput during operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces time-consuming mechanical recalibration operations with rapid computational error compensation using the trained ML model. The computational approach processes measurements and applies corrections in real-time without requiring physical system interruptions or lengthy calibration sequences. This substitution maintains measurement stability while preserving manufacturing throughput by eliminating the productivity loss associated with frequent physical recalibration.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20240053280A1Methods And Systems For Systematic Error Compensation Across A Fleet Of Metrology Systems Based On A Trained Error Evaluation Model
Publication Date: 2024.02.15 KLA CORP
  • US20240053280A1 patent drawing
  • US20240053280A1 patent drawing
  • US20240053280A1 patent drawing

AI summary

Methods and systems for compensating systematic errors across a fleet of metrology systems based on a trained error evaluation model to improve matching of measurement results across the fleet are described herein. In one aspect, the error evaluation model is a machine learning based model trained based on a set of composite measurement matching signals. Composite measurement matching signals are generated based on measurement signals generated by each target measurement system and corresponding model-based measurement signals associated with each target measurement system and reference measurement system. The training data set also includes an indication of whether each target system is operating within specification, an indication of the values of system model parameter of each target system, or both. In some embodiments, the composite measurement matching signals driving the training of the error evaluation model are weighted differently, for example, based on measurement sensitivity, measurement noise, or both.