Thermal Shield Gas Flow for Lithography Temperature Stability

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Solution Overview

Problem

Lithographic apparatuses face challenges in maintaining temperature stability of substrates due to thermal loads, leading to imaging errors, and existing thermal shields are either bulky or complex with liquid-based solutions.

Innovation Solution

A system with a thermal shield comprising a gap between two walls, where gas from a source flows through the gap to reduce thermal fluctuations, with inlet and outlet openings to manage temperature stability, and optionally includes a layer of thermal insulation and underpressure to enhance performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thermal shield made only of insulating material is used, then thermal insulating performance is improved, but volume increases and space is consumed

Engineering Contradiction:
Improvethermal insulating performanceVSAvoidvolume of thermal shield
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The thermal shield combines insulating material with a thermally conditioning system (gas flow or liquid circulation) to create a composite structure. The insulating material provides base thermal protection while the active thermally conditioning system enhances insulation performance, allowing reduction of overall shield volume while maintaining or improving thermal protection effectiveness.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces gas flow or liquid circulation within the thermal shield structure to actively remove heat. This pneumatic/hydraulic approach provides dynamic thermal management that replaces the need for bulky passive insulation, achieving superior thermal protection with reduced volume through active heat transport mechanisms.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If a wall thermally conditioned with liquid is used, then thermal shielding performance is improved and volume is reduced, but device complexity increases and risk of damage increases

Engineering Contradiction:
Improvethermal shielding performanceVSAvoidcomplexity of liquid tight seals
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs gas flow or liquid circulation systems integrated into the thermal shield walls to actively condition thermal environments. This approach achieves effective thermal shielding with compact design while managing the complexity of fluid sealing through careful system integration and selection of appropriate sealing mechanisms for the specific application context.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The system dynamically adjusts thermal conditioning parameters (gas flow rate, liquid flow rate, temperature) to optimize thermal shielding performance. By changing operational parameters rather than relying solely on fixed structural design, the system achieves adaptability and maintains effectiveness across varying thermal loads without requiring overly complex mechanical structures.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If thermal shields are used to insulate substrate handling spaces, then temperature stability is improved, but device complexity and space consumption increase

Engineering Contradiction:
Improvetemperature stability of substrateVSAvoidcomplexity of thermal shield system
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent uses gas flow or liquid circulation systems integrated into the thermal shield to actively maintain temperature stability of the substrate handling space. This active thermal management approach provides precise temperature control with reduced shield thickness compared to passive insulation, thereby reducing overall system complexity while maintaining stability.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The system dynamically adjusts thermal conditioning parameters (flow rates, temperatures) in response to thermal loads to maintain optimal temperature stability. This adaptive parameter control enables effective substrate temperature management with a more compact and less complex thermal shield design compared to static passive insulation systems.

Inventive Principle:
Principle #35Parameter changes

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 system effectively reduces thermal fluctuations in the substrate handling space, maintaining temperature stability without the bulkiness of insulating materials or the complexity of liquid-based systems, thereby minimizing imaging errors.

Implementation Method 1

the system is adapted to direct the flow of gas from the gas source to enter the gap through the at least one inlet opening, to flow through the gap and out of the gap to outside the space through the at least one outlet opening thereby to reduce thermal fluctuations in the space

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3137944B1Lithographic apparatus and device manufacturing method
Publication Date: 2020.03.04 ASML NETHERLANDS BV
  • EP3137944B1 patent drawingFigure 1
  • EP3137944B1 patent drawingFigure 2
  • EP3137944B1 patent drawingFigure 3

AI summary

A system for use with a lithographic apparatus, the system configured to handle a substrate, wherein the system is adapted to be coupled to a gas source (30), the system comprising: a space (105) through which the substrate passes; and a thermal shield (110) for thermally insulating the space from a thermal load originating outside the space, the thermal shield comprising: a first wall (1100) and a second wall (1200) with a gap (1300) therebetween, the first wall being positioned between the space and the second wall; at least one inlet opening (1400) configured to allow a flow of gas (212) from the gas source to enter the gap from outside the space; and at least one outlet opening (1500) configured to allow the flow of gas to exit the gap to outside of the space, wherein the system is adapted to direct the flow of gas from the gas source to enter the gap through the at least one inlet opening, to flow through the gap and out of the gap to outside the space through the at least one outlet opening thereby to reduce thermal fluctuations in the space due to the thermal load originating outside the space.