Conformal Chuck for Large Substrate Precision
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Solution Overview
Problem
Large substrate processing stages face challenges in maintaining precision due to non-flat working surfaces, which can result in substrates being presented outside the depth of field of processing tools, making it difficult to achieve the required dimensional accuracy and alignment.
Innovation Solution
The use of a compliant chuck with air bearing pucks and pre-loading mechanisms to ensure a uniform and constant distance between the chuck and the base, allowing the chuck to conform to the base's shape and maintain flatness under projection cameras, thereby presenting a flat substrate within the camera's depth of field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the stage is scaled up to accommodate large substrates (Gen.6 or larger), then the substrate processing capability is improved, but maintaining high precision becomes difficult due to non-flat working surfaces
Solution Approach 1:
The base is designed with a localized flat subregion rather than requiring the entire large stage surface to be flat. This subregion is positioned directly beneath the projection camera to ensure that only the critical processing area maintains high flatness, while other areas of the large stage can have varying topography. This resolves the contradiction by providing local precision where needed without requiring global flatness across the entire large substrate area.
2Manufacturing precision
If the entire stage surface is flattened to maintain precision, then substrate alignment is improved, but the cost and time required for flattening increases significantly
Solution Approach 1:
Instead of flattening the entire large stage surface, only a localized subregion beneath the projection camera is flattened. This dramatically reduces the time and resources required for the flattening process while maintaining the necessary precision for substrate processing. The rest of the stage surface can retain its original topography, avoiding unnecessary processing time and costs.
3Stability of the object's composition
If a rigid base structure is used to maintain stability, then structural integrity is improved, but the ability to conform to non-flat surfaces and maintain contact uniformity deteriorates
Solution Approach 1:
The chuck is designed with compliant or flexible characteristics that allow it to conform to the base surface topology. This compliance enables the chuck to maintain uniform contact with the base across non-flat surfaces, ensuring reliable substrate positioning and processing. The flexible chuck design resolves the contradiction by adapting to base irregularities without compromising structural stability.
Solution Approach 2:
The solution introduces vertical adjustment capability through air bearing pucks with pre-loading mechanisms. These pucks can independently adjust their height along the vertical dimension, compensating for base surface variations and maintaining constant contact pressure between the chuck and base. This dimensional freedom allows the system to maintain reliability on non-flat surfaces while preserving base structural integrity.
4Reliability
If air bearing pucks are used to maintain uniform distance between chuck and base, then contact uniformity is improved, but the complexity of the stage structure increases
Solution Approach 1:
Air bearing pucks are employed to provide uniform separation and contact between the chuck and base. These pneumatic elements can be integrated into the existing stage architecture, providing the necessary compliance and contact uniformity without requiring fundamentally new structural approaches. The air bearing technology, while adding some complexity, offers aĉç solution that balances reliability improvement with acceptable structural complexity.
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 effectively maintains the required precision and alignment of large substrates during processing, reducing the need for expensive and time-consuming flattening of the entire stage and allowing for the use of larger, more complex substrates in semiconductor and LCD manufacturing.
Implementation Method 1
The chuck is supported above the base on a cushion of air
Implementation Method 2
pre-loading mechanisms to ensure a uniform and constant distance between the chuck and the base
Data Source
AI summary
An improved stage for the processing of large, thin substrates, such as glass and semiconductor panels. Processing includes lithography, inspection, metrology, grinding, and the like. The stage includes a chuck that moves over a base relative to a device for processing a substrate. The chuck conforms to a geometry of the base while moving relative to the base.