Two-Phase Thermal Conditioning for Lithography Cooling Precision
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Solution Overview
Problem
Conventional cooling methods for lithographic apparatuses using small channels result in laminar flow, leading to reduced cooling efficiency and increased temperatures, which can affect the accuracy of the apparatus due to heat radiation and poor heat transfer coefficients.
Innovation Solution
A two-phase thermal conditioning system is introduced, comprising an evaporator for heat extraction through fluid evaporation, a condenser for heat removal through condensation, fluid lines forming a circuit, a pump for circulation, an accumulator with a heat exchanger for temperature regulation, and a temperature sensor to maintain constant fluid temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If small cooling channels are used, then design flexibility and weight are improved, but cooling efficiency deteriorates due to laminar flow formation
Solution Approach 1:
The patent employs two-phase flow (liquid-vapor transition) of coolant in small channels to achieve high heat transfer coefficients. The phase change process absorbs and releases large amounts of latent heat, enabling effective cooling despite the small channel dimensions that would otherwise produce laminar flow with poor heat transfer.
2Adaptability or versatility
If small cooling channels are used, then design flexibility is improved, but heat transfer coefficient deteriorates due to laminar flow
Solution Approach 1:
The invention utilizes phase transitions of the coolant (evaporation and condensation) to achieve high heat transfer coefficients in small channels. The latent heat transfer during phase change dramatically improves thermal performance compared to single-phase laminar flow, enabling flexible channel design without sacrificing heat transfer efficiency.
Solution Approach 2:
The patent changes the physical state parameters of the coolant from single-phase liquid to two-phase liquid-vapor mixture. This parameter change transforms the heat transfer mechanism from convection-dominated laminar flow to phase-change-dominated heat transfer, achieving high heat transfer coefficients in small channels.
3Temperature
If conventional liquid cooling is used, then heat extraction is achieved, but temperature control precision deteriorates
Solution Approach 1:
The two-phase cooling system provides superior temperature control precision through the phase transition mechanism. The latent heat absorption during evaporation and release during condensation create a self-regulating effect that maintains more stable temperatures, and the system includes temperature sensors and controllers to actively monitor and adjust cooling parameters for precise temperature maintenance.
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 two-phase system enhances cooling efficiency, allowing for the use of small channels while maintaining accurate temperature control, reducing mass flow requirements and eliminating the need for lubricants, thus improving the operational accuracy and cleanliness of the lithographic apparatus.
Implementation Method 1
an evaporator to be positioned in thermal contact with the part of the lithographic apparatus for extracting heat from the part by evaporation of a fluid inside the evaporator
Implementation Method 2
a condenser to be positioned at a distance from the part of the lithographic apparatus for removing heat from the fluid inside the condenser by condensation of the fluid inside the condenser
Implementation Method 3
an accumulator configured to hold fluid; wherein the accumulator is in fluid communication with the circuit and comprises a heat exchanger to transfer heat from or to fluid inside the accumulator
Data Source
AI summary
A conditioning system for conditioning a part of a lithographic apparatus, includes an evaporator positioned in thermal contact with the part for extracting heat from the part by evaporation of a fluid inside the evaporator; a condenser for removing heat from the fluid inside the condenser; fluid lines arranged between the evaporator and the condenser to form a fluid circuit; a pump arranged in the circuit to circulate the fluid in the circuit; an accumulator to hold fluid, wherein the accumulator is in fluid communication with the circuit and comprises a heat exchanger to transfer heat from or to fluid inside the accumulator; a temperature sensor to provide a signal representative of the fluid temperature; and a controller to maintain a substantially constant temperature of the fluid inside the circuit by regulating the amount of heat transferred by the heat exchanger based on the signal.