Integrated Optical Mass Metrology for Substrate Thickness
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Solution Overview
Problem
Current substrate processing systems face challenges in accurately and cost-effectively monitoring substrate mass changes during processing, as mass metrology systems are costly and limited in data usage, and existing solutions do not efficiently combine optical and mass metrology for real-time process control.
Innovation Solution
A metrology system that integrates optical and mass metrology using a combination of optical sensors, a spectrometer, and machine learning to generate a spatial thickness distribution model, where spectral data is correlated with mass or mass change data to determine substrate thickness and adjust process parameters, reducing the need for high-cost standalone metrology systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical metrology is used for measuring critical dimensions, then measurement precision is improved, but the device complexity increases due to multiple separate metrology tools
Solution Approach 1:
The patent combines multiple separate metrology tools (optical metrology tool and mass metrology tool) into a single integrated metrology tool. The optical system includes both an optical detector for measuring critical dimensions and a mass detector for measuring overlay, eliminating the need for separate tools and reducing overall system complexity while maintaining measurement precision
2Adaptability or versatility
If multiple separate metrology tools are used, then measurement coverage is improved, but the measurement time increases
Solution Approach 1:
The integrated metrology tool performs both optical measurements (critical dimensions) and mass measurements (overlay) simultaneously or in rapid succession using a single instrument. This eliminates the time required to transfer samples between separate tools and enables comprehensive measurement coverage in a single measurement cycle
Solution Approach 2:
The system performs preliminary alignment and positioning of the sample stage once, then sequentially performs both optical and mass measurements without requiring sample removal or re-positioning. This preliminary positioning action eliminates repeated setup time and accelerates the overall measurement process
3Measurement precision
If separate optical and mass metrology tools are used, then measurement accuracy is improved, but the sample handling complexity increases
Solution Approach 1:
The patent integrates both optical and mass measurement capabilities within a single tool, eliminating the need for complex sample handling procedures required to transfer samples between separate tools. The single-stage design allows both measurement types to be performed on the same sample in the same location without removal or re-positioning
Solution Approach 2:
The integrated metrology tool acts as an intermediary system that unifies the measurement processes. Instead of requiring external sample handling mechanisms to move samples between separate tools, the integrated system provides direct access to both optical and mass measurement capabilities through a single instrument interface
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
This integrated system provides accurate and cost-effective real-time monitoring of substrate thickness and process control, enabling improved etch depth predictions and process adjustments, thereby enhancing substrate processing efficiency and reducing production costs.
Implementation Method 1
optical critical dimension (CD) measurements of a first grating and a second grating
Implementation Method 2
mass overlay measurements between the first grating and the second grating
Data Source
Figure 1A
Figure 1B~1C
Figure 1D
AI summary
A metrology system for substrate processing includes an optical metrology station including a plurality of optical sensors to measure spectra from a plurality of measurement locations on a substrate. A plurality of fiber cables are connected to the plurality of optical sensors. A spectrometer is selectively connected to the plurality of fiber cables. A mass metrology station measures at least one of a mass or mass change of the substrate. A controller includes a modelling module to generate thickness values at the plurality of measurement locations based on the spectra from the plurality of measurement locations and a learned model. A spatial modelling module generates a spatial thickness distribution model for the substrate based on the thickness values at the plurality of measurement locations from the modelling module and the at least one of the mass or the mass change from the mass metrology station.