Laser Triangulation Measurement for Hot Wafer Showerhead Gap Control
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Solution Overview
Problem
Existing substrate processing systems face challenges in accurately measuring the orientation of gas distribution devices relative to substrate supports during high-temperature processing, as conventional sensors are not suitable for temperatures above 80 degrees Celsius due to thermal expansion and bowing issues.
Innovation Solution
A laser triangulation sensor is used to measure distances between the gas distribution device and the substrate support within a substrate processing chamber, allowing for precise adjustment of the gas distribution device's orientation by actuating adjustment mechanisms based on these measurements, even at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sensors are used to measure distances between gas distribution device and substrate support, then the system structure remains simple, but measurement accuracy deteriorates at temperatures above 80 degrees Celsius due to thermal expansion and bowing
Solution Approach 1:
The patent replaces conventional mechanical/contact-based sensors with a laser triangulation sensor that uses optical fields to measure distances. The laser triangulation sensor transmits laser light through a window and measures the position of reflected light to determine distances between the gas distribution device and substrate support, eliminating mechanical contact and enabling operation at high temperatures above 80°C without thermal expansion issues.
Solution Approach 2:
The patent introduces a window as an intermediary element that allows laser light to pass through the chamber wall for distance measurements. This window enables the laser triangulation sensor to measure distances externally without direct exposure to the high-temperature processing environment, solving the temperature limitation while maintaining measurement accuracy.
2Manufacturing precision
If the gas distribution device orientation is not accurately controlled during high-temperature processing, then the processing can proceed without complex measurement systems, but substrate treatment accuracy deteriorates
Solution Approach 1:
The patent implements a feedback control system where the laser triangulation sensor continuously measures the distance and orientation of the gas distribution device relative to the substrate support during processing. The controller receives these measurements and adjusts the gas distribution device orientation in real-time to maintain optimal positioning, ensuring substrate treatment accuracy while using a relatively simple optical measurement system.
Solution Approach 2:
The patent replaces complex mechanical measurement systems with an optical laser triangulation system. The laser triangulation sensor uses light reflection and triangulation geometry to measure distances and orientations non-contactively, providing the necessary feedback for accurate gas distribution device positioning without requiring complex mechanical linkages or contact sensors that would be problematic at high temperatures.
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 approach enables accurate and precise control of the gas distribution device's orientation during processing, improving the accuracy of substrate treatments and the quality of resulting substrates by compensating for thermal expansion and bowing effects.
Implementation Method 1
the measurement feature is configured to: reflect light from the laser triangulation sensor onto the first surface when the laser triangulation sensor outputs light to a first surface of the measurement feature; and reflect light from the laser triangulation sensor onto the second surface when the laser triangulation sensor outputs light to a second surface of the measurement feature
Implementation Method 2
A laser triangulation sensor is used to measure distances between the gas distribution device and the substrate support within a substrate processing chamber
Data Source
AI summary
A substrate processing system includes a laser triangulation sensor configured to transmit and receive light through a window of an exterior wall of a substrate processing chamber. A controller is configured to: position the laser triangulation sensor such that the laser triangulation sensor transmits light onto a measurement feature arranged between a first surface of a substrate support and a second surface of a gas distribution device, where the second surface faces the first surface; and while the laser triangulation sensor transmits light onto the measurement feature, determine a first distance between the first and second surfaces based on a difference between: a second distance between the laser triangulation sensor and the first surface measured using the laser triangulation sensor; and a third distance between the laser triangulation sensor and the second surface measured using the laser triangulation sensor.