Wafer Cassette Mapping With Deep Learning Slot Classification

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Solution Overview

Problem

Current substrate-mapping solutions in semiconductor and allied industries, such as those used in semiconductor fabs and solar-cell production, face challenges in accurately determining the classification state of substrates within carriers due to varying substrate diameters, types, and thicknesses, leading to issues like cross-loading, double-loading, and protrusions, which existing technologies struggle to address effectively.

Innovation Solution

A deep-convolutional neural-network-based substrate-mapping system that uses image acquisition and processing to classify the state of substrates within carriers, employing a pre-trained network to automatically tag each location as empty, properly loaded, double-loaded, cross-loaded, or protruded, and can handle diverse substrate types and thicknesses by capturing and analyzing images with minimal lighting requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional substrate-mapping solutions are used, then the system is simpler to implement, but the measurement precision and reliability of substrate state classification deteriorate due to varying substrate diameters, types, and thicknesses

Engineering Contradiction:
Improvesubstrate state classification accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system changes the approach from traditional geometric and optical parameter-based detection to deep learning parameter extraction. The neural network learns optimal parameters automatically from training data, enabling accurate classification of substrates with varying diameters, types, and thicknesses without requiring complex manual parameter tuning

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional mechanical and optical sensing systems with an image-based deep learning system. Instead of using complex mechanical sensors or optical interferometers, the system uses standard imaging combined with convolutional neural networks to achieve high-precision substrate state detection

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

2Productivity

If manual inspection methods are used, then the device complexity is lower, but the productivity and time efficiency deteriorate as inspection of entire carriers takes excessive time

Engineering Contradiction:
Improvecarrier inspection speedVSAvoidinspection time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The system performs preliminary action by pre-training the neural network with extensive substrate images before actual inspection. This preliminary training phase enables the network to rapidly classify substrates during production, achieving high-speed inspection without requiring complex real-time processing algorithms

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates digital copies (images) of substrates and processes them through the neural network. This copying approach allows parallel processing of multiple substrate images simultaneously, dramatically increasing inspection throughput compared to sequential manual or mechanical inspection methods

Inventive Principle:
Principle #26Copying

3Reliability

If existing mapping technologies are used, then the equipment setup is simpler, but the reliability of detecting cross-loading, double-loading, and protrusions deteriorates

Engineering Contradiction:
Improvesubstrate placement detection reliabilityVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system transitions from two-dimensional image capture to three-dimensional substrate state classification. The neural network analyzes images to infer depth information and spatial relationships, enabling reliable detection of protrusions, cross-loading, and double-loading conditions without requiring complex multi-angle imaging or 3D scanning hardware

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS20250014165A1Substrate mapping using deep neural-networks
Publication Date: 2025.01.09 ONTO INNOVATION INC
  • US20250014165A1 patent drawing
  • US20250014165A1 patent drawing
  • US20250014165A1 patent drawing

AI summary

Various examples include a system and network to map of substrates within a substrate carrier (e.g., such as silicon wafers within a wafer cassette), and a classification of a state of each substrate, as well as the carrier in which the substrates are placed. In various examples provided herein, an image acquisition system, such as a camera, acquires multiple images of the substrates within the carrier. The image or images are then processed with a deep-convolutional neural-network to classify a state of the substrate relative to a substrate slot including empty slots, occupied slots (e.g., properly loaded slots), double-loaded slots, cross-slotted, and protruded (where a substrate is not fully loaded into a slot).