Substrate Centering Contact Geometry for Notch-Safe Alignment
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Solution Overview
Problem
Conventional substrate processing apparatuses face challenges in achieving high centering accuracy due to misalignment between the substrate and the substrate support, especially when the substrate has a cut or notch, which affects the effectiveness of processes like bevel etching.
Innovation Solution
A centering device with three or more contact members arranged around the substrate support, each with a contact surface that can move to sandwich the substrate, where the contact surfaces are designed to have a linear or curved shape with a radius of curvature larger than the substrate, preventing contact member entry into the cut and enhancing alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional pusher-based centering is used, then centering function is achieved, but throughput is reduced due to two-stage process
Solution Approach 1:
The centering device is segmented into three or more independent contact members arranged around the substrate support. Each contact member can move independently in mutually different directions to push the substrate toward the center, enabling parallel operation that improves throughput while maintaining precision.
Solution Approach 2:
The contact members are pre-positioned around the substrate support before substrate placement. When the substrate is placed, the contact members simultaneously engage and push the substrate to the center in a single stage, eliminating the need for preliminary measurement and subsequent correction steps.
2Ease of operation
If contact members are arranged to surround substrate support, then centering function is achieved, but centering accuracy decreases when substrate has cut or notch
Solution Approach 1:
The contact members are designed with specific geometric characteristics - contact surfaces with linear or curved shapes having radii larger than the substrate radius. This local geometric quality ensures that contact members engage the substrate at optimal points away from the cut or notch, maintaining centering accuracy regardless of substrate orientation.
Solution Approach 2:
The contact members are positioned asymmetrically around the substrate support at different angular locations. This asymmetric arrangement ensures that at least some contact members can effectively engage the substrate to push it toward the center, even when the substrate has asymmetric features like cuts or notches at various orientations.
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 significantly improves centering accuracy by preventing the contact members from entering the notch, thereby reducing eccentric deviation and ensuring precise alignment between the substrate and the substrate support, enhancing the throughput and quality of processes like bevel etching.
Implementation Method 1
a suction unit configured to suck and hold the substrate on the substrate support by exhausting air between the substrate positioned by the centering device and the substrate support
Data Source
AI summary
A centering device has three or more contact members each having a contact surface capable of contacting an end face of a substrate supported by a substrate support. These contact members are arranged to surround the substrate support in a horizontal plane with the contact surfaces facing an end face of the substrate. These contact members move toward the substrate in the mutually different directions to sandwich the substrate. Each contact surface is finished such that a contactable region formed to intersect the horizontal plane has a linear shape or a curved shape having a center of curvature located on the substrate side and having the radius of curvature larger than the radius of the substrate and is longer than an arc formed by cutting out the circumference of the substrate by the cut.