Infrared Chuck Calibration with Flow Shielding Against Gas Distortion
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Solution Overview
Problem
Existing infrared camera devices for calibrating wafer substrate chucks face challenges in accurately measuring temperature distributions due to air or gas currents, especially at higher temperatures, leading to distorted measurements.
Innovation Solution
A flow shielding plate is positioned between the probe wafer and the infrared camera device, maintaining a gap to create a thermos flask effect, ensuring accurate calibration by preventing airflow interference, and using temperature probes for precise calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a probe wafer with temperature probes is used for calibration, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a flow shielding plate as an intermediary component between the probe wafer and the infrared camera. This plate mediates the interaction by blocking gas currents from directly reaching the probe wafer surface, thereby enabling accurate infrared measurements without requiring complex sealed calibration chambers. The shielding plate simplifies the overall arrangement while maintaining measurement precision.
Solution Approach 2:
The patent extracts the harmful gas current flow from the measurement path by introducing the flow shielding plate. The plate captures and redirects the gas currents away from the probe wafer surface, effectively removing this interfering factor from the calibration measurement path and enabling straightforward infrared temperature measurement.
2Ease of operation
If gas currents are present during calibration, then ease of operation is improved, but measurement precision deteriorates due to flow distortion
Solution Approach 1:
The flow shielding plate serves as a mediator that allows gas currents to continue flowing in the chamber (maintaining ease of operation) while simultaneously blocking them from reaching the probe wafer surface. This enables simple calibration operations without compromising measurement precision, as the shielding plate intercepts and redirects the gas flows away from the measurement area.
3Measurement precision
If the flow shielding plate is positioned close to the probe wafer, then measurement precision is improved by enhancing thermos flask effect, but device complexity increases due to precise positioning requirements
Solution Approach 1:
The patent optimizes the gap spacing parameter between the flow shielding plate and the probe wafer to a specific range (1-10 mm) that balances measurement precision with positioning feasibility. This parameter optimization allows the thermos flask effect to be sufficiently strong for accurate measurements while avoiding the need for extremely tight tolerances that would complicate the positioning system.
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
The solution enables precise calibration of the infrared camera device by minimizing airflow interference, allowing for accurate temperature measurement and control of the chuck, thereby improving temperature control device calibration.
Implementation Method 1
With a suitable selection of the flow shielding plate or its contours, as well as with a suitable gap spacing, the so-called thermos flask effect can be achieved between the probe wafer and the flow shielding plate, meaning that the flows in question cannot establish themselves above the surface of the probe wafer.
Implementation Method 2
which is held at a distance from the special wafer by a slit and is optically transparent to infrared radiation emitted by the probe wafer heated by the chuck and to be detected by the infrared camera device
Data Source
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AI summary
The present invention relates to a calibration assembly and a corresponding calibration method for calibrating an infrared camera device (50) for sensing a temperature of a chuck (10), which can be heated by a temperature control means (15), for wafer substrates. The calibration assembly is equipped with a probe wafer (20), which is situated on the chuck (10) and has a plurality of temperature probes (20a, 20b); a flow shield plate (30), which is held spaced by a gap (25) with a gap distance (d) between the probe wafer (20) and the infrared camera device (50) and is optically transparent to infrared radiation emitted by the probe wafer (20), which is heated by the chuck (10), and to be sensed by the infrared camera device (50); a temperature-sensing means (40) for sensing the various temperatures of the temperature probes (20a, 20b); and a calibration means (100), to which the various sensed temperatures of the temperature probes (20a, 20b) can be fed in order to calibrate the infrared camera device (50) on the basis of the various sensed temperatures of the temperature probes (20a, 20b).