Substrate Support Burl Structure for Uniform Fluid Lubrication
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Solution Overview
Problem
It has proven challenging to drive fluid uniformly and reliably through a large number of burls in a substrate table to reduce frictional forces and prevent substrate distortion during lithographic processes.
Innovation Solution
A substrate table with a substrate support featuring a plurality of holes through a base member and burl structures with openings to these holes, allowing for an outward flow of fluid to provide a lubricating effect and reduce friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fluid is driven through a large number of burls to reduce frictional forces, then substrate distortion is reduced, but uniform and reliable fluid flow becomes challenging
Solution Approach 1:
The burl structures are designed with internal porous channels that allow fluid to flow through them. This porous structure enables the fluid to reach the interface between the substrate and substrate table, reducing frictional forces and preventing substrate distortion while maintaining reliable and uniform fluid distribution across all burls
Solution Approach 2:
The invention uses fluid (gas or liquid) pressure to create a lubricating effect between the substrate and substrate table. By driving fluid through the burl structures, a fluid film is formed that reduces frictional forces during substrate loading and unloading, thereby reducing substrate distortion
2Ease of manufacture
If burls are used to support the substrate, then ease of manufacturing and contaminant management is improved, but frictional forces causing substrate distortion increase
Solution Approach 1:
The invention introduces fluid pressure systems to the burl structure, allowing fluid to be pumped through internal channels to the substrate interface. This creates a lubricating film that dramatically reduces frictional forces between the substrate and burls, eliminating the harmful friction effect while preserving the manufacturing advantages of burl structures
Solution Approach 2:
The burl structures incorporate porous materials or porous-like internal channel structures that enable fluid permeation. This allows the solid burl structures to simultaneously provide mechanical support and facilitate fluid flow, reducing friction through lubrication while maintaining the ease of manufacture and contaminant management benefits of discrete burl elements
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 solution enables efficient and reliable fluid flow through the burl structures, effectively reducing frictional forces and minimizing substrate distortion, thereby improving the manufacturing process and substrate support performance.
Implementation Method 1
The substrate table is configured to provide an outward flow of fluid through all of the openings in each of one or more of the burl structures
Implementation Method 2
driving fluid through the burls to provide a lubricating effect
Data Source
AI summary
Substrate tables and methods of manufacturing substrate supports for substrate tables. In one arrangement, a plurality of holes are formed through a base member. A burl formation member is joined to the base member. A plurality of burl structures are formed in the burl formation member. Each burl structure includes a distal surface that contacts, in use, a substrate being supported. Each burl structure has an opening to at least one of the holes formed through the base member.