Substrate Warpage Measurement via Rotational Position Alignment
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Solution Overview
Problem
Existing substrate inspection methods face challenges in accurately calculating warpage amounts due to changes in the rotational position of the holding table, which can introduce errors in shape data comparison between reference and target substrates.
Innovation Solution
A method involving a camera system that takes images of the end surfaces of both reference and target substrates while rotating, processes the images to obtain shape data, and calculates warpage by finding the difference under aligned rotational positions of the holding table, thereby suppressing positional change-related components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If shape data is obtained by comparing end surface images of reference and target substrates, then warpage amount can be calculated, but measurement precision deteriorates due to rotational position changes of the holding table
Solution Approach 1:
The system detects the rotational position of the holding table using a sensor and feeds this information back to the image processing unit. This feedback mechanism allows the system to identify and correct for rotational position changes, ensuring that shape data is compared at corresponding rotational positions, thereby maintaining measurement precision and reliability
Solution Approach 2:
The system changes the parameter of rotational position alignment by detecting the holding table's rotational position and adjusting the image comparison process accordingly. By synchronizing the rotational positions between reference and target substrate images, the system eliminates measurement errors caused by rotational misalignment
2Loss of information
If images are taken while rotating the holding table to capture entire circumference, then complete shape data is obtained, but positional changes during rotation introduce measurement errors
Solution Approach 1:
The system performs preliminary detection of the holding table's rotational position before comparing shape data. By预先 detecting the rotational position, the system can ensure that images taken at different rotational positions are correctly aligned during comparison, preventing measurement errors while maintaining complete shape data acquisition
Solution Approach 2:
The system replaces manual or mechanical alignment methods with an automated detection and correction mechanism. Using sensors and image processing algorithms, the system automatically identifies rotational position changes and adjusts the comparison process, eliminating the need for precise mechanical alignment while maintaining measurement accuracy
Data Source
AI summary
A substrate inspection method includes a first process of taking, while rotating a holding table where a reference substrate is held, an image of an end surface of the reference substrate; a second process of obtaining shape data on the end surface of the reference substrate by processing the image; a third process of taking, while rotating the holding table where a target substrate is held, an image of an end surface of the target substrate; a fourth process of obtaining shape data on the end surface of the target substrate by processing the image; and a fifth process of calculating a warpage amount of the target substrate by obtaining a difference between the shape data obtained in the second process and in the fourth process under a condition that a rotational position of the holding table in the first process coincides with that in the third process.