Lithography Wafer-Stage Cable Support with UHMWPE Particle Control
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Solution Overview
Problem
EUV lithography apparatuses produce particles due to collisions and abrasions between moving components, leading to wafer contamination and reduced yield.
Innovation Solution
Incorporation of ultra-high molecular weight polyethylene (UHMWPE) in a protective unit that collides with a support unit to reduce particle production, along with a support unit that restricts cable sagging and twisting, and a grounding unit to manage electrical energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional materials are used for the protective unit, then the structure provides basic protection, but particle production occurs due to collision and abrasion
Solution Approach 1:
The patent applies parameter changes by selecting a specific material (UHMWPE) with unique properties - extremely high molecular weight and high impact strength - to fundamentally alter the collision dynamics. This material parameter change reduces particle generation during collisions between the protective unit and support unit, directly addressing the harmful particle production issue while maintaining protective function.
Solution Approach 2:
The patent employs composite material strategy by using UHMWPE, which combines multiple desirable properties: high molecular weight for reduced wear, high impact strength for collision resistance, and low friction coefficient for smooth operation. This composite approach creates a material that simultaneously addresses multiple requirements - protection, particle reduction, and operational smoothness.
2Ease of operation
If the cable is allowed to move freely with stage movement, then flexibility is maintained, but the cable sags and twists causing operational issues
Solution Approach 1:
The patent introduces a support unit as an intermediary component between the cable and the stage structure. This support unit, consisting of clamps and connection members, actively manages cable position during stage movement, preventing sagging and twisting while allowing necessary flexibility. The support unit mediates between the conflicting requirements of flexibility and stability.
3Manufacturing precision
If the protective unit collides with the support unit during stage movement, then positional accuracy is maintained, but particle generation occurs from the collision
Solution Approach 1:
The patent fundamentally changes the material parameters of the protective unit by using UHMWPE with extremely high molecular weight and high impact strength. This parameter change transforms the collision characteristics - the material can undergo collision necessary for positional accuracy while generating minimal particles due to its superior mechanical properties and resistance to wear and abrasion.
Data Source
AI summary
Provided is a lithography apparatus including a wafer stage, a cable connected to the wafer stage, the cable being configured to bend based on the wafer stage moving, a support unit configured to prevent the cable from sagging, the support unit including a plurality of clamps configured to restrict movement of the cable and a connection member connecting the plurality of clamps to each other, and a protective unit under the cable, the protective unit being configured to collide with the support unit based on the wafer stage moving, wherein the protective unit includes ultra-high molecular weight polyethylene (UHMWPE).