Deep Auto-Encoder Monitoring for Semiconductor Tool Anomaly Detection

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Solution Overview

Problem

Current methods for Equipment Health Monitoring (EHM) and Fault Detection in semiconductor processing chambers are inefficient in detecting short-time signal perturbations and anomalies in time-series data from sensors, leading to false positives and requiring significant feature engineering, which is time-consuming and limited to specific tool types or recipes.

Innovation Solution

A deep auto-encoder type neural network is employed to derive a model of training time-series traces, allowing for the detection of anomalies by calculating mean square error between input and output traces, with the server declaring anomalies when the error exceeds a pre-determined value, enabling real-time monitoring and corrective actions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If statistical methods are used for anomaly detection, then false positive rates are high, but detection precision is low

Engineering Contradiction:
Improveanomaly detection precisionVSAvoidfalse positive rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent transforms the anomaly detection problem from statistical hypothesis testing to neural network reconstruction error analysis. By changing the detection parameter from statistical significance thresholds to reconstruction error magnitudes, the system achieves both high precision in detecting true anomalies and low false positive rates, as the neural network learns the normal operational patterns and only flags deviations that exceed learned thresholds.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional statistical mechanical methods (hypothesis testing, p-values, confidence intervals) with a neural network-based information processing system. This substitution allows the system to capture complex non-linear relationships in sensor data while providing more reliable anomaly detection with reduced false positives, as the neural network implicitly models the joint distribution of sensor readings without requiring explicit statistical assumptions.

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

2Measurement precision

If classical machine learning methods with feature engineering are used, then model accuracy is improved, but time consumption and complexity increase

Engineering Contradiction:
Improveanomaly detection accuracyVSAvoidfeature engineering time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements self-service by allowing the neural network to automatically learn relevant features from raw sensor data during training. The autoencoder architecture inherently performs feature extraction and selection by learning to compress and reconstruct the input data, eliminating the need for manual feature engineering by domain experts. This self-organizing approach significantly reduces time consumption while maintaining or improving detection accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent performs preliminary action by pre-training the neural network on extensive normal operational data before deployment. This preliminary training phase allows the system to learn the baseline patterns and relationships in sensor data, so that during actual operation, anomaly detection can proceed rapidly without requiring real-time feature engineering. The model is prepared in advance to handle various operational conditions.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If traditional machine learning models are rebuilt for different tool types or recipes, then detection accuracy is maintained, but productivity decreases

Engineering Contradiction:
Improvedetection accuracyVSAvoidmodel rebuilding speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent achieves universality by designing a neural network architecture that can handle multiple tool types and recipes within a single model. The autoencoder learns a unified representation of sensor data patterns across different processing conditions, allowing the same model to detect anomalies in various chamber types and recipe configurations without requiring separate models. This multi-functional approach maintains detection accuracy across diverse scenarios while eliminating the need for time-consuming model rebuilding.

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

Solution Approach 2:

The patent introduces dynamics by enabling the neural network to adapt to different operational contexts through continuous learning or fine-tuning mechanisms. Rather than requiring complete model rebuilding when tool types or recipes change, the system can dynamically adjust to new conditions by learning from additional data or adapting existing representations, thereby maintaining high detection accuracy while significantly improving productivity and reducing downtime.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11948061B2Deep auto-encoder for equipment health monitoring and fault detection in semiconductor and display process equipment tools
Publication Date: 2024.04.02 APPLIED MATERIALS INC
  • US11948061B2 patent drawing
  • US11948061B2 patent drawing
  • US11948061B2 patent drawing

AI summary

Implementations described herein generally relate to a method for detecting anomalies in time-series traces received from sensors of manufacturing tools. A server feeds a set of training time-series traces to a neural network configured to derive a model of the training time-series traces that minimizes reconstruction error of the training time-series traces. The server extracts a set of input time-series traces from one or more sensors associated with one or more manufacturing tools configured to produce a silicon substrate. The server feeds the set of input time-series traces to the trained neural network to produce a set of output time series traces reconstructed based on the model. The server calculates a mean square error between a first input time series trace of the set of input time series traces and a corresponding first output time series trace of the set of output time-series traces. The server declares the sensor corresponding to the first input time-series trace as having an anomaly when the mean square error exceeds a pre-determined value.