Spin Chuck Rotation Center Calibration Using Acceleration Sensors
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Solution Overview
Problem
Current substrate processing systems face challenges in accurately positioning substrates on spin chucks due to the need for expensive CCD cameras for determining the rotation center, which increases manufacturing costs and limits miniaturization, as well as requiring complex image processing and increased computer load.
Innovation Solution
A substrate processing system that uses a jig with a piezoelectric acceleration sensor to measure centrifugal acceleration, allowing for the calculation of eccentricity and determination of the rotation center without image processing, thereby enabling accurate positioning with a compact and cost-effective solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a CCD camera is used to determine the rotation center of the spin chuck, then the positioning accuracy is improved, but the manufacturing cost increases and the system size increases
Solution Approach 1:
The patent replaces the optical measurement system (CCD camera) with a mechanical measurement system using a jig equipped with an acceleration sensor. The jig is placed on the spin chuck and rotated, and the acceleration sensor measures centrifugal acceleration to determine the rotation center through arithmetic calculations. This substitution eliminates the need for expensive CCD cameras while maintaining measurement accuracy.
Solution Approach 2:
The patent uses a simple jig with an acceleration sensor instead of an expensive CCD camera. The jig can be easily manufactured and replaced if needed, making it a cost-effective solution compared to the expensive and complex CCD camera system.
2Measurement precision
If a CCD camera is used to determine the rotation center, then the positioning accuracy is improved, but the system size increases
Solution Approach 1:
The patent replaces the bulky optical system (CCD camera requiring overhead space) with a compact mechanical system. The acceleration sensor in the jig is a small component that can be easily integrated, eliminating the need for large overhead camera mounting space and enabling miniaturization of the wet processing unit.
3Measurement precision
If image processing is used to process high-resolution image data, then the positioning accuracy is improved, but the processing time increases and computer load increases
Solution Approach 1:
The patent replaces complex image processing with simple arithmetic calculations. The acceleration sensor directly measures centrifugal acceleration, and the rotation center is determined through mathematical calculations based on acceleration data. This eliminates the need for time-consuming image processing operations while maintaining accuracy.
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 allows for accurate and inexpensive substrate positioning, reducing the need for expensive equipment and image processing, while miniaturizing the system by eliminating the requirement for CCD cameras, thus enhancing the system's efficiency and cost-effectiveness.
Implementation Method 1
measuring means for measuring centrifugal acceleration imparted to a measuring position on the jig when the substrate holding device holding the jig is rotated at a fixed angular velocity
Implementation Method 2
A substrate processing system according to the present invention having a processing unit for processing a substrate held substantially horizontally by a substrate holding device rotatable about a vertical axis, and capable of acquiring data on a wafer placing position on the substrate holding device, at which a substrate carrying means is required to place the substrate beforehand, includes: a jig to be transferred to the substrate holding device by the substrate carrying means: a measuring means for measuring centrifugal acceleration imparted to a measuring position on the jig
Data Source
AI summary
In a substrate processing system for processing a substrate, such as a wafer W, held by a substrate holding device rotatable about a vertical axis, such as a spin chuck, a jig is placed on the substrate holding device, and centrifugal acceleration imparted to a predetermined measuring position on the jig and an eccentricity of the measuring position from the rotation center of the spin chuck are determined. The position of the rotation center is determined on the basis of centrifugal accelerations imparted to the measuring position when the jig is placed at three different positions and eccentricities of the measuring position from the rotation center when the jig is placed at the three different positions. Data on a substrate placing position, the center of the substrate placed at which coincides with the rotation center, is stored as data of a substrate placing position at which a substrate is to be placed.