Projection Lithography Mirror Cutout for Contactless Thermal Control

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Solution Overview

Problem

Existing projection exposure apparatuses for semiconductor lithography face challenges in maintaining imaging quality due to mechanical vibrations and complex thermal management systems, which affect the performance of optical elements, particularly in EUV systems.

Innovation Solution

A temperature-regulating device is introduced within the cutout of a mirror without mechanical contact, utilizing a temperature-regulating body with a cavity for fluid convection and laser irradiation to manage thermal loads, decoupling vibrations and enabling adjustable temperature control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If water cooling with mechanical connections is used to regulate mirror temperature, then temperature control is achieved, but vibrations are transmitted to the mirror affecting imaging quality

Engineering Contradiction:

Improvemirror temperature controlVSAvoidvibrations

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical water cooling system with a contactless temperature regulation system. A temperature-regulating body is positioned in the cutout of the mirror without mechanical connection, using radiation-based heating and cooling elements to control mirror temperature while eliminating vibration transmission pathways.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The temperature-regulating body acts as an intermediary element between the mirror and the cooling/heating system. It receives radiation from heating/cooling elements and transfers thermal energy to the mirror through the cutout space, enabling temperature control without direct mechanical contact.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If water flow is used for temperature regulation, then thermal load is reduced, but flow-induced vibrations occur degrading imaging quality

Engineering Contradiction:

Improvethermal load regulationVSAvoidflow-induced vibrations

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent eliminates the water flow mechanism entirely and replaces it with radiation-based thermal regulation. Heating and cooling elements emit radiation that is absorbed by the temperature-regulating body and subsequently by the mirror, achieving thermal management without fluid flow and its associated vibrations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If contactless temperature regulation without cooling and heating elements is used, then vibrations are reduced, but temperature control complexity increases

Engineering Contradiction:

ImprovevibrationsVSAvoidtemperature regulation system

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines heating and cooling functions into a single integrated temperature-regulating body positioned in the mirror cutout. This unified structure simplifies the overall system architecture compared to separate heating and cooling systems, while maintaining contactless operation to eliminate vibrations.

Inventive Principle:

Principle #5Merging (Combining)

4Productivity

If intensity of light from illumination system is increased, then lithography performance is improved, but thermal load on optical elements increases

Engineering Contradiction:

Improvelithography performanceVSAvoidthermal load

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent implements preliminary temperature regulation by positioning the temperature-regulating body in the cutout before thermal accumulation occurs. The radiation-based heating and cooling elements can preemptively adjust the mirror temperature to compensate for expected thermal loads from high-intensity illumination, maintaining optimal operating conditions.

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 solution effectively reduces vibrations and thermal stresses on mirrors, enhancing imaging quality by allowing precise temperature regulation and minimizing mechanical interference, thus improving the performance of projection exposure apparatuses.

Implementation Method 1

The temperature regulation by the fluid can be effected by convection, for example.

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

a mechanism for cooling the fluid in the temperature-regulating body by laser irradiation can be present. In this case, the fluid, which can include rubidium and/or argon, for example, can be irradiated by a laser and cools down as a result.

Methodology Applied

Scientific EffectLaser cooling: Laser

Data Source

PatentUS12436361B2Projection exposure apparatus for semiconductor lithography

Publication Date: 2025.10.07 CARL ZEISS SMT GMBH

AI summary

A projection exposure apparatus for semiconductor lithography includes a mirror and a temperature-regulating device for regulating temperature on the basis of radiation. The mirror includes at least one cutout. The temperature-regulating device includes a temperature-regulating body arranged without contact in the cutout of the mirror. The temperature-regulating body has a cavity. A fluid for temperature regulation of the temperature-regulating body is present in the cavity.