Lithography Air Bearing Stage for Flatness Correction Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing stage systems for lithographic apparatuses face instability issues when positioning substrates or patterning devices that are not entirely flat, due to warping or other low-order Zernike shape deviations.
Innovation Solution
A stage system incorporating a plurality of air bearing devices, each comprising an air bearing body with a free surface, a primary channel with an inlet opening, and a secondary channel system with discharge openings, where the flow resistance in the secondary channel system is higher than in the primary channel, allowing for stable positioning and shape correction of objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If jets of pressurized gas are used to flatten the object, then shape deviations can be corrected, but the system becomes unstable
Solution Approach 1:
The patent employs air bearing devices that utilize pneumatic principles to support and position the object. Instead of using jets of pressurized gas that cause instability, the invention uses controlled air bearings with specific flow resistance characteristics to provide stable levitation and positioning while maintaining object flatness.
Solution Approach 2:
The patent changes the flow resistance parameter of the air bearing system by designing a secondary channel system with higher flow resistance than the primary channel. This parameter modification stabilizes the pneumatic field and prevents oscillations, thereby resolving the instability issue while maintaining shape correction capability.
2Measurement precision
If the object is not entirely flat, then positioning accuracy is adversely affected, but applying force to flatten it causes instability
Solution Approach 1:
The invention uses air bearing technology to non-contactly support the object, eliminating mechanical forces that cause instability. The pneumatic system gently lifts and positions the object, allowing accurate positioning without the adverse effects of mechanical clamping or forceful flattening.
Solution Approach 2:
By modifying the flow resistance parameters of the air bearing channels, the system achieves stable operation that maintains both positioning accuracy and object flatness without causing instability. The controlled pneumatic pressure ensures precise positioning while preserving object integrity.
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
The proposed stage system achieves stable and accurate positioning of objects relative to a surface, while also allowing for the correction of shape deviations, thereby enhancing the reliability and precision of lithographic processes.
Implementation Method 1
an air bearing device comprises: an air bearing body, which has a free surface
Implementation Method 2
wherein the flow resistance in the secondary channel system is higher than the flow resistance in the primary channel
Data Source
AI summary
A system for positioning, a stage system, a lithographic apparatus, a method for positioning and a method for manufacturing a device in which use is made of a stage system that includes a plurality of gas bearing devices. Each gas bearing device includes: a gas bearing body, which has a free surface, a primary channel which extends through the gas bearing body and has an inlet opening in the free surface, a secondary channel system which extends through the gas bearing body and which has a plurality of discharge openings in the free surface. The flow resistance in the secondary channel system is higher than the flow resistance in the primary channel.