Substrate Holding Apparatus Warping Correction
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Solution Overview
Problem
Conventional substrate holding apparatuses face challenges in achieving high accuracy positioning and strong pressing of substrates, particularly with miniaturized circuit patterns, and in maintaining substrate flatness due to warping, which affects the sensitivity of optical inspection devices.
Innovation Solution
A substrate holding apparatus featuring a rotating bed with position restriction units that press the substrate at multiple points on its upper circumference to maintain precise positioning and a pressing unit that uses centrifugal force to securely hold the substrate during rotation, preventing warping and ensuring consistent distance for optical inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the substrate is positioned on the substrate holding apparatus so that the normal line of the substrate passing through the center of gravity coincides with the rotation axis, then the rotation of the substrate becomes smooth, but the positioning accuracy deteriorates due to substrate warping
Solution Approach 1:
The pressing unit presses the substrate against the inclined surface before rotation begins, pre-correcting warping and establishing accurate positioning in advance. This preliminary action ensures that when rotation starts, the substrate is already in the correct position, avoiding the need to choose between smooth rotation and positioning accuracy.
Solution Approach 2:
The pressing unit applies variable pressing force to the substrate, changing the physical state of the substrate by reducing warping. This parameter change (applying pressure) directly addresses the positioning accuracy issue while maintaining rotation smoothness through the inclined surface geometry.
2Adaptability or versatility
If the substrate is held by contacting only the lower side of the rounded outer circumferential side surface, then the front and back surfaces remain non-contacting for inspection, but the substrate tilts when the normal line does not coincide with the rotation axis
Solution Approach 1:
The inclined surface acts as an intermediary between the substrate and the pressing unit. The pressing unit applies force to the substrate, and the inclined surface translates this force into a component that corrects warping and maintains horizontal positioning, while still allowing non-contact inspection of the front and back surfaces.
Solution Approach 2:
The pressing unit applies localized pressure at specific points on the substrate's outer circumferential side surface. This localized action corrects warping and maintains positioning without requiring contact with the front or back surfaces, preserving inspection capability while improving stability.
3Manufacturing precision
If gas blowing is applied to the backside of the substrate to correct warping, then substrate flatness improves, but stronger pressing force is needed to prevent floating during rotation
Solution Approach 1:
The system replaces pure gas blowing with a mechanical pressing system using the pressing unit and inclined surface. This mechanical approach provides more controlled and efficient warping correction without the instability and floating issues associated with gas blowing, reducing the overall pressing force needed during rotation.
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 solution enables high accuracy positioning and strong pressing of substrates, reducing warping and maintaining consistent distance for improved optical inspection sensitivity, even with miniaturized patterns and frequent heat processing.
Implementation Method 1
a pressing unit which rotates together with the rotating bed and presses the substrate against the inclined surface by pressing a plurality of points on the circumference on the upper side during the rotation
Data Source
AI summary
In order to enable high accuracy positioning and strong pressing of a substrate, the present invention provides a substrate holding apparatus including: a rotating bed having an inclined surface supporting a lower side of an outer circumferential side surface of the substrate, which bed rotates on a normal line of the substrate as the rotation axis together with the substrate; a position restriction unit rotating together with the rotating bed and restricting the substrate in a predetermined position on the rotating bed by pressing a plurality of points on the circumference on an upper side of the outer circumferential side surface of the substrate prior to the rotation; and a pressing unit rotating together with the rotating bed and pressing the substrate against the inclined surface by pressing a plurality of points on the upper side of the outer circumferential side surface of the substrate during the rotation.