Substrate State Detection with Oblique-View Filter Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In substrate processing chambers, the limited arrangement of cameras for monitoring leads to reduced accuracy in image processing and target state detection due to oblique viewing, causing deformation in image data and decreased detection accuracy.
Innovation Solution
A state detection method that involves taking an image of the imaging target, applying a filter corrected based on the positional relationship between the target and the imaging part, and adjusting the filter coefficient according to the inclination angle between the imaging direction and a reference direction, using a two-dimensional filter with end portions corrected to 0.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a camera is disposed in a substrate processing chamber to monitor the processing, then the monitoring function is provided, but the camera must obliquely view the target due to limited arrangement space, causing image deformation and reduced detection accuracy
Solution Approach 1:
The patent changes the parameters of image processing by correcting filter coefficients based on the inclination angle of the camera. Instead of changing the camera's physical position, the system adjusts the digital processing parameters (filter coefficients) to compensate for the oblique viewing angle, thereby maintaining detection accuracy despite the constrained arrangement space.
2Adaptability or versatility
If the camera obliquely views the imaging target due to limited arrangement space, then the camera can be installed in the chamber, but the image data becomes deformed and filter processing accuracy is reduced
Solution Approach 1:
The system compensates for image deformation caused by oblique viewing by dynamically adjusting filter coefficients based on the camera's inclination angle. This parameter change in the digital domain allows the system to maintain processing accuracy while accepting various camera arrangement configurations.
Solution Approach 2:
The patent introduces asymmetric correction by applying different filter coefficients to different regions of the image based on the inclination angle. The correction is not uniform across the entire image but is tailored to the specific geometric distortion caused by the oblique viewing angle, thereby restoring accuracy.
3Productivity
If filter processing is applied to oblique images without correction, then image processing is performed, but the detection accuracy is reduced due to image deformation
Solution Approach 1:
The system performs preliminary correction by adjusting the filter coefficients before applying the filter to the image. This pre-correction based on the known inclination angle ensures that the subsequent filtering operation produces accurate results, maintaining both efficiency and precision without requiring reprocessing.
Data Source
AI summary
Suppressed is reduction of accuracy of detecting a state of a target even in a case there is a limitation on an imaging direction in which an image of an imaging target can be taken. A state detection method disclosed in the specification of the present application includes: a step of taking an image of at least one imaging target regarding processing of a substrate by an imaging part and outputting the image; a step of applying a filter previously prepared to the image in accordance with the imaging target; and a step of detecting a state of the imaging target based on the image to which the filter is applied, wherein a filter coefficient of the filter applied to the image is corrected based on a positional relationship between the imaging target whose image is taken and the imaging part.