Aerostatic Bearings and Differential Pumping for Vacuum Substrate Processing
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Solution Overview
Problem
The processing of large glass sheets for Flat Panel Displays and semiconductor substrates is challenging due to their brittle nature, requiring gentle handling and precise coating without contamination, which is difficult with existing methods that often involve contact handling and large, costly clean room equipment for vacuum processing.
Innovation Solution
A method and apparatus using differentially pumped grooves to create a low-pressure or near-vacuum environment for in-line processing, allowing for precise chemical vapor deposition and plasma vapor deposition with controlled thickness and cleanliness, and incorporating aerostatic bearings for non-contact handling and simultaneous processing on both sides of the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Chemical Vapor Deposition is used to achieve precise thickness coatings, then coating precision is improved, but the size of the vacuum vessel required increases and processing time increases
Solution Approach 1:
The patent divides the vacuum processing into multiple stages using differentially pumped grooves that create sequential vacuum zones along the substrate path. Each groove section maintains a different pressure level, allowing CVD processing in a localized vacuum region rather than requiring a large vacuum chamber for the entire substrate area.
Solution Approach 2:
The aerostatic bearings act as intermediaries that enable non-contact support and positioning of the substrate while allowing differential pumping through the bearing structure. The bearing design includes pumping grooves that facilitate vacuum creation in specific zones without requiring a complete vacuum environment throughout the entire processing apparatus.
2Device complexity
If conventional contact handling methods are used for substrate processing, then device complexity is reduced, but contamination and surface defects increase
Solution Approach 1:
The patent replaces mechanical contact handling systems with aerostatic bearing support, where a thin film of gas provides non-contact support for the substrate. This eliminates mechanical contact that could cause surface defects or contamination while maintaining simple and effective substrate support and transport.
Solution Approach 2:
The aerostatic bearings utilize pneumatic principles by introducing compressed gas through grooves in the bearing structure, creating a pressurized gas film that lifts and supports the substrate without contact. This pneumatic system provides contamination-free handling while maintaining positional control.
3Area of stationary object
If large vacuum chambers are used to accommodate larger FPD glass substrates, then substrate size capacity is improved, but processing time and cost increase
Solution Approach 1:
The vacuum system is segmented into multiple zones created by differentially pumped grooves along the substrate path. Only the specific zone where coating or processing occurs requires high vacuum, while other zones can operate at higher pressures, dramatically reducing the volume that needs to be evacuated and reducing pump-down time.
Solution Approach 2:
The patent applies vacuum conditions locally only where needed for the coating process, rather than creating a vacuum environment for the entire large-area substrate handling system. The differential pumping grooves create localized vacuum zones that move with the substrate, maintaining high vacuum only in the processing region.
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
Enables precise and contamination-free coating and baking of large substrates with reduced clean room space requirements, improving processing efficiency and cost-effectiveness by allowing sequential or simultaneous processing within a contained vacuum environment.
Implementation Method 1
aerostatic bearings for non-contact handling
Implementation Method 2
differentially pumped grooves to create a low-pressure or near-vacuum environment
Implementation Method 3
precise chemical vapor deposition and plasma vapor deposition with controlled thickness
Implementation Method 4
precise chemical vapor deposition and plasma vapor deposition with controlled thickness
Data Source
AI summary
A method and apparatus for coating and baking and deposition of surfaces on glass substrate or flexible substrate, such as films and thin glass sheets or other similar work pieces as it transitions thru and between small gaps of aero-static or hydro-static porous media bearings and differentially pumped vacuum grooves, in a non-contact manner, in order to process within a vacuum environment. The process is also intended to incorporate simultaneous and immediately sequential ordering of various processes.