Cornered Fluid Handling Structure for Lithographic Meniscus Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current fluid handling systems in lithographic apparatuses face challenges in maintaining liquid between the projection system and the substrate during high-speed scanning motions, leading to liquid loss and bubble formation, which affects the precision and efficiency of the imaging process.

Innovation Solution

A fluid handling structure with a cornered shape geometry, featuring meniscus pinning openings and fluid supply openings, is designed to maintain liquid confinement by using a gas drag extractor principle, where the openings are arranged to reduce the force on the meniscus and prevent liquid droplet creation during scanning and stepping motions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the substrate is scanned at high speed through the projection system, then productivity is improved, but liquid confinement is compromised leading to liquid loss and bubble formation

Engineering Contradiction:
Improvescanning speedVSAvoidliquid confinement
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The fluid handling structure is segmented into multiple cornered sections with openings at each corner, allowing distributed liquid confinement forces to counteract the centrifugal effects of high-speed scanning. This segmentation enables the system to maintain liquid confinement reliability while achieving high scanning speeds through the projection system.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If conventional fluid handling structures are used, then device complexity is kept simple, but liquid loss occurs during scanning motions

Engineering Contradiction:
Improvefluid handling structureVSAvoidliquid loss
Core Design Contradiction:
Device complexityVSLoss of substance

Solution Approach 1:

The fluid handling structure employs asymmetric cornered geometry with openings positioned at the corners rather than a conventional symmetric circular or rectangular shape. This asymmetric design creates optimal meniscus pinning effects that prevent liquid loss during scanning motions, achieving superior liquid retention with only moderate increases in structural complexity.

Inventive Principle:
Principle #4Asymmetry

3Ease of operation

If the meniscus is allowed to move freely during scanning, then ease of operation is improved, but bubble formation occurs affecting manufacturing precision

Engineering Contradiction:
Improvefluid handlingVSAvoidimaging precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The cornered openings are pre-positioned to create meniscus pinning effects before scanning begins. This preliminary arrangement of the fluid interface at the cornered openings ensures that the meniscus remains stable and pinned during scanning motions, preventing bubble formation and maintaining manufacturing precision throughout the imaging process.

Inventive Principle:
Principle #10Preliminary action

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 configuration allows for increased scanning and stepping speeds while minimizing liquid loss and bubble formation, thereby enhancing the throughput and precision of the lithographic process.

Implementation Method 1

using a gas drag extractor principle, where the openings are arranged to reduce the force on the meniscus and prevent liquid droplet creation

Methodology Applied
Scientific EffectGas drag: Drag

Implementation Method 2

a plurality of meniscus pinning openings arranged in plan, in a first cornered shape

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP2131241B1Fluid handling structure, lithographic apparatus and device manufacturing method
Publication Date: 2019.07.31 ASML NETHERLANDS BV
  • EP2131241B1 patent drawingFigure 1
  • EP2131241B1 patent drawingFigure 2~4
  • EP2131241B1 patent drawingFigure 5~6

AI summary

A fluid handling structure is disclosed in which measures are taken to increase the speed at which meniscus breakdown occurs. Measures include the shape of a plurality of fluid extraction openings (50) and the shape and density of a plurality of fluid supply openings in the fluid handling structure.