Wafer Transport Cover Hole Layout for Oxidation Control
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Solution Overview
Problem
Conventional substrate processing apparatuses, such as CMP apparatuses, fail to efficiently suppress oxidation and corrosion of substrates during transport, as inert gas supply methods either inadequately replace air or risk disrupting the liquid film on the substrate surface when the substrate is moved.
Innovation Solution
A transport apparatus with a cover member having a higher opening ratio on its outer peripheral portion than its central portion, which supplies inert gas through holes to the substrate's surface, ensuring efficient air replacement without disrupting the liquid film, even during substrate movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of inert gas is supplied to the entire surface of the substrate, then the inert gas on the substrate surface is not replaced by air, but the liquid film formed on the substrate surface may be blown off
Solution Approach 1:
The patent applies local quality by creating different opening ratios in different regions of the cover member. The outer peripheral portion has a higher opening ratio (first opening ratio) while the central portion has a lower opening ratio (second opening ratio). This localized differentiation allows inert gas to be supplied more intensely at the edges where air replacement is most critical during substrate movement, while reducing gas supply at the center to prevent liquid film disruption.
2Object-affected harmful factors
If a small amount of inert gas is supplied to the substrate, then the liquid film is preserved, but the air on the substrate surface cannot be effectively replaced when the substrate is moved
Solution Approach 1:
The patent differentiates the opening ratio locally across the cover member surface. The outer peripheral portion has a higher opening ratio to provide sufficient inert gas supply for effective air replacement during substrate movement, while the central portion maintains a lower opening ratio to preserve liquid film integrity.
3Ease of operation
If inert gas is supplied uniformly across the entire substrate surface, then the supply method is simple, but the oxygen concentration cannot be effectively controlled during substrate movement
Solution Approach 1:
The patent implements local quality by varying the opening ratio of the cover member across different regions. The outer peripheral portion has a higher opening ratio while the central portion has a lower opening ratio, creating a non-uniform gas supply pattern that effectively controls oxygen concentration during substrate movement while maintaining reasonable operational simplicity.
Solution Approach 2:
The patent applies asymmetry by creating an asymmetric opening ratio distribution in the cover member. The outer peripheral portion and central portion have different opening ratios, breaking the uniform symmetry to optimize oxygen concentration control during substrate movement according to the specific airflow patterns and oxidation risks at different locations.
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 configuration effectively maintains a low oxygen concentration on the substrate surface, reducing oxidation and corrosion while minimizing inert gas usage and preventing liquid film disruption, thus enhancing substrate protection during processing.
Implementation Method 1
The gas supply member is configured to supply an inert gas to the surface of the substrate via the plurality of holes of the cover member
Implementation Method 2
when a large amount of inert gas is supplied to the entire surface of the substrate, it is not preferable because the liquid film formed on the substrate surface may be blown off, which may instead lead to oxidation and corrosion of the substrate surface
Data Source
AI summary
A transport apparatus includes a hand, a drive mechanism, a cover member, and a gas supply member. The hand is configured to hold a wafer. The drive mechanism is configured to transport the wafer by moving the hand. The cover member has an opposing surface opposed to a surface of the wafer held by the hand and is formed with a plurality of holes opened in the opposing surface. The gas supply member is configured to supply an inert gas to the surface of the wafer via the plurality of holes of the cover member. The plurality of holes are formed in the opposing surface so that an opening ratio of an outer peripheral portion of the opposing surface is higher than an opening ratio of a central portion of the opposing surface.