Substrate Reflectometry Alignment for Off-Center Thickness Profiling
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Solution Overview
Problem
Current substrate processing systems face challenges in accurately measuring film thickness and uniformity across substrates, particularly when substrates are not centered on the holder, leading to inefficiencies and potential non-uniformities in manufacturing processes.
Innovation Solution
An integrated reflectometry system with a substrate holder that rotates and moves linearly, allowing sensors to capture measurements from multiple points on the substrate while applying coordinate transformations to correct for offset positions, enabling precise determination of film thickness and uniformity profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the substrate is not centered on the substrate holder, then the measurement system cannot accurately measure film thickness and uniformity, but re-centering the substrate manually increases measurement time and reduces productivity
Solution Approach 1:
The system automatically detects substrate offset and corrects it through coordinated rotational and linear actuator movements without requiring manual intervention. The processing device calculates the offset based on sensor data and autonomously adjusts the substrate holder position to center the substrate, enabling self-correction that maintains measurement precision while preserving productivity.
Solution Approach 2:
The patent replaces manual mechanical re-centering operations with an automated control system that uses sensors to detect offset and actuators to correct position. This substitution of manual mechanical adjustment with an automated sensing-actuation system eliminates the trade-off between measurement accuracy and productivity.
2Manufacturing precision
If the substrate holder rotates to measure multiple target positions, then comprehensive uniformity profiling is achieved, but offset between sensor field of view and target positions increases measurement error
Solution Approach 1:
The system continuously monitors the position of the substrate relative to the sensor field of view during rotation and uses this feedback to dynamically adjust the linear position of the substrate holder. This closed-loop feedback ensures that the sensor remains aligned with the intended target positions on the substrate throughout the rotational scanning process, maintaining measurement accuracy while enabling comprehensive uniformity profiling.
Solution Approach 2:
The patent employs dynamic coordination between rotational and linear actuators during the measurement process. Rather than static positioning, the system dynamically adjusts the linear position of the substrate holder in real-time during rotation to compensate for offset, enabling accurate measurements across all target positions while maintaining comprehensive uniformity profiling capability.
3Measurement precision
If manual re-centering procedures are implemented to improve measurement accuracy, then measurement precision improves, but system complexity and operation time increase
Solution Approach 1:
The system performs automatic substrate centering through integrated sensors and actuators controlled by a processing device, eliminating the need for manual re-centering procedures. This self-service capability maintains high measurement precision while reducing operational complexity and measurement time by automating the positioning 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
This solution enables real-time monitoring and correction of film thickness and uniformity issues, improving process reliability and efficiency by providing accurate measurements and alerts for process drifts and non-uniformities, even when substrates are not perfectly centered.
Implementation Method 1
an integrated reflectometry system
Implementation Method 2
an integrated reflectometry system
Data Source
AI summary
An apparatus includes a substrate holder, a first actuator to rotate the substrate holder, a second actuator to move the substrate holder linearly, a first sensor to generate one or more first measurements or images of the substrate, a second sensor to generate one or more second measurements of target positions on the substrate, and a processing device. The processing device estimates a position of the substrate on the substrate holder and causes the first actuator to rotate the substrate holder about a first axis. The rotation causes an offset between a field of view of the second sensor and a target position on the substrate due to the substrate not being centered on the substrate holder. The processing device causes the second actuator to move the substrate holder linearly along a second axis to correct the offset. The processing device determines a profile across a surface of the substrate based on the one or more second measurements of the target positions.