Large Spot Spectral Sensing for Real-Time Wafer Uniformity Control
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Solution Overview
Problem
Advanced etch and deposition processes in semiconductor manufacturing result in non-uniform features across wafers due to variations in critical dimensions and etch depths, requiring additional time and resources for metrology and process adjustments.
Innovation Solution
A large beam spot metrology tool integrated with a process chamber for real-time monitoring and a control system to obtain metrology samples over a wafer's surface, combined with computational systems to denoise optical metrology data and determine optimal process settings using machine learning models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional metrology methods are used to identify non-uniformities, then measurement precision is improved, but loss of time increases due to additional time required for identifying problems and determining corrections
Solution Approach 1:
The system performs preliminary metrology measurements during the fabrication process itself, capturing wafer non-uniformity data before the wafer leaves the process chamber. This preliminary action eliminates the need for separate post-process metrology steps, thereby reducing total time while maintaining measurement precision through real-time data capture
Solution Approach 2:
The metrology tool operates continuously during wafer processing, with the beam spot scanning across the wafer surface without interruption to the fabrication process. This continuous operation allows simultaneous process execution and measurement, eliminating idle time between processing and measurement operations
2Manufacturing precision
If comprehensive metrology sampling is performed across the wafer surface, then manufacturing precision is improved by identifying non-uniformities, but device complexity increases due to integration of metrology tool with process chamber
Solution Approach 1:
The metrology tool is physically integrated with the process chamber, merging two previously separate systems (fabrication equipment and metrology equipment) into a single unified system. This integration allows the metrology beam to access the wafer during processing without requiring wafer removal, achieving comprehensive sampling while managing complexity through systematic design
Solution Approach 2:
The process chamber is designed to serve dual functions: performing fabrication operations and enabling metrology measurements. The chamber structure and wafer handling mechanisms are configured to accommodate both process execution and optical measurement, reducing the need for separate dedicated metrology equipment
3Productivity
If real-time metrology monitoring is implemented during fabrication, then productivity is improved by reducing rework time, but device complexity increases due to integration requirements
Solution Approach 1:
The system implements real-time feedback by continuously monitoring wafer non-uniformity during fabrication and using this data to dynamically adjust process parameters. The control system receives metrology data and automatically modifies process settings to compensate for detected variations, enabling closed-loop control that improves productivity through immediate correction
Solution Approach 2:
The system performs self-diagnosis and self-correction by automatically analyzing metrology data and adjusting process parameters without external intervention. The control system independently identifies non-uniformities and implements corrections, reducing the need for operator involvement and accelerating the correction process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances wafer uniformity by reducing within-wafer and wafer-to-wafer variations, improving processing efficiency and reducing the time required for process adjustments.
Implementation Method 1
direct an incident light beam onto a wafer with a beam spot of at least about 1 mm on the wafer's surface, and detect a metrology signal from the wafer in response to illumination with the incident light beam
Data Source
AI summary
A large beam spot spectral reflectometer system for measuring a substrate is provided. Hardware components for collecting in situ large beam spot optical signals is disclosed. Machine learning models for denoising large beam spot optical signals are disclosed. Machine learning models for interpreting in situ optical data and facilitating process control are also disclosed.