Wafer Cleaning Apparatus with Overlapping Turning Shaft
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Solution Overview
Problem
Existing substrate cleaning technologies face challenges in reducing the size of cleaning apparatuses while maintaining effective detergency, especially for larger wafers, due to the complexity and size requirements of existing cleaning mechanisms.
Innovation Solution
A substrate cleaning apparatus with a first and second cleaning member, horizontally movable and rotatable respectively, using a common turning shaft to clean the central and peripheral zones of the substrate's rear surface, with the turning shaft positioned to overlap with the substrate for size reduction and improved detergency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple brushes are used to improve detergency, then cleaning effectiveness is improved, but apparatus size increases
Solution Approach 1:
The substrate surface is divided into multiple zones (central zone and peripheral zones), with different cleaning members assigned to different zones. This segmentation allows efficient cleaning of each zone while avoiding the need for a single large cleaning mechanism that would increase apparatus size.
Solution Approach 2:
The cleaning mechanism utilizes vertical movement (elevation and depression) of cleaning members in addition to horizontal movement. The cleaning members are elevated to contact the substrate surface only when needed, and depressed to retract when not in use. This dimensional approach allows multiple cleaning members to share compact space without interfering with each other.
2Reliability
If cleaning brush moves through rotational center to clean central zone, then complete coverage is achieved, but moving distance increases process time
Solution Approach 1:
The substrate is divided into a central zone and peripheral zones, with dedicated cleaning members for each zone. The first cleaning member is positioned to clean the central zone directly without requiring movement through the rotational center, while the second cleaning member handles the peripheral zones. This segmentation eliminates unnecessary travel distance and reduces process time.
Solution Approach 2:
The cleaning members are pre-positioned at optimal locations to contact their respective zones on the substrate. The first cleaning member is positioned to contact the central zone, and the second cleaning member is positioned to contact the peripheral zones, eliminating the need for long-distance movement during the cleaning process.
3Ease of manufacture
If support arm is located outside substrate circumference, then cleaning mechanism is accessible, but turning radius exceeds substrate radius increasing apparatus size
Solution Approach 1:
The driving mechanism of the support arm is nested inside the cup that surrounds the substrate circumference, rather than being located outside. This nesting approach allows the support arm to rotate with a turning radius equal to or less than the substrate radius, reducing the overall apparatus size while maintaining full accessibility and functionality of the cleaning mechanism.
Data Source
AI summary
There are provided first and second cleaning members which are configured to clean a central zone in a rear surface of a wafer when the wafer held by an absorption pad is horizontally held, and configured to clean a peripheral zone in the rear surface of the wafer when the wafer is held by the spin chuck. Due to the provision of the first and second cleaning members, detergency can be improved as compared with a case in which only one cleaning member is used. The first and second cleaning members are configured to be horizontally turned by a common turning shaft. When the central zone in the rear surface of the wafer is cleaned, the turning shaft is located to be overlapped with the wafer. Since the turning shaft is located by using the moving area of the wafer, a size of an apparatus can be reduced.