Machine Learning Endpoint Detection for Substrate Metrology

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Solution Overview

Problem

Conventional endpoint detection systems in microelectronics manufacturing are inadequate for meeting the increasing demands of precision and accuracy due to variations in substrate processing, leading to issues like under-processing and over-processing, which result in substandard devices.

Innovation Solution

A machine learning-based system that collects and analyzes spectral data to provide real-time metrology measurements by training models on historical data, allowing for precise endpoint detection and process termination, thereby preventing defects and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional endpoint detection systems are used, then the manufacturing process can be monitored, but the precision and accuracy of endpoint detection are insufficient due to variations in substrate processing

Engineering Contradiction:
Improveendpoint detection precisionVSAvoiddetection reliability under process variations
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary actions by collecting historical spectral data from multiple manufacturing systems and process conditions, then training machine learning models in advance. This pre-training on diverse historical data enables the models to adapt to various process variations without requiring real-time recalibration, thereby improving both precision and reliability of endpoint detection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the parameter of detection methodology from conventional fixed-threshold methods to adaptive machine learning models that can dynamically adjust to process variations. The ML models learn optimal detection parameters from historical data, enabling accurate endpoint detection across different manufacturing systems and process conditions.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If real-time monitoring is implemented to improve quality control, then product quality improves, but the system complexity increases

Engineering Contradiction:
Improvesubstrate processing qualityVSAvoidmonitoring system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention replaces complex mechanical and optical endpoint detection systems with machine learning-based software models. Instead of relying on sophisticated hardware systems to detect endpoint, the solution uses ML models that analyze spectral data, thereby reducing hardware complexity while maintaining or improving detection accuracy through intelligent algorithms.

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

Solution Approach 2:

The system creates a virtual model of the manufacturing process using machine learning models trained on historical spectral data. This digital twin or copy of the process enables prediction and monitoring without requiring equivalent physical measurement systems at every manufacturing location, simplifying the overall monitoring infrastructure.

Inventive Principle:
Principle #26Copying

3Adaptability or versatility

If machine learning models are trained on historical spectral data from multiple manufacturing systems, then the model generalization improves, but the data processing complexity increases

Engineering Contradiction:
Improvemodel generalization across systemsVSAvoiddata processing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system performs preliminary data processing and model training using historical spectral data from multiple manufacturing systems before deployment. By pre-processing the data and training models in advance, the system achieves broad generalization across different manufacturing systems without requiring complex real-time data processing during actual substrate processing.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS20220397515A1Obtaining substrate metrology measurement values using machine learning
Publication Date: 2022.12.15 APPLIED MATERIALS INC
  • US20220397515A1 patent drawing
  • US20220397515A1 patent drawing
  • US20220397515A1 patent drawing

AI summary

A machine learning model trained to provide metrology measurements for a substrate is provided. Training data generated for a prior substrate processed according to a prior process is provided to train the model. The training data includes a training input including a subset of historical spectral data extracted from a normalized set of historical spectral data collected for the prior substrate during the prior process. The subset of historical spectral data includes an indication of historical spectral features associated with a particular type of metrology measurement. The training data also includes a training output including a historical metrology measurement obtained for the prior substrate, the historical metrology measurement associated with the particular type of metrology measurement. Spectral data is collected for a current substrate processed according to a current process. A subset of current data extracted from a normalized set of the spectral data for the current substrate is provided as input to the trained model. Metrology measurement data for the current substrate is extracted from one or more outputs of the trained model.