Two-Phase Lithographic Cooling via Evaporation and Condensation
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Solution Overview
Problem
Conventional cooling methods for lithographic apparatuses using small channels result in laminar flow, leading to poor cooling efficiency and increased temperatures, which can affect the accuracy of the apparatus due to heat radiation and reduced 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 fluid flow (liquid-vapor transition) in the cooling channels to achieve high heat transfer coefficients. The fluid evaporates at the heated surface, forming vapor bubbles that enhance heat transfer, then condenses in the condenser section. This phase transition mechanism allows efficient cooling in compact channels without relying on high flow velocities, thus maintaining reliability while minimizing weight.
2Power
If water cooling is used, then heat extraction capability is improved, but temperature control precision deteriorates due to poor cooling efficiency in small channels
Solution Approach 1:
The two-phase cooling system utilizes controlled evaporation and condensation of the cooling fluid to achieve superior temperature control precision. The phase change occurs at constant temperature, providing stable thermal conditions. The evaporator section absorbs heat at a constant saturation temperature, while the condenser releases heat at a constant temperature, enabling precise thermal management of the lithographic apparatus components.
Solution Approach 2:
The system incorporates temperature sensors and control mechanisms that monitor the thermal state of cooled components and adjust the cooling fluid flow rate and pressure accordingly. This feedback control ensures that the temperature of critical components remains within specified tolerances, maintaining manufacturing precision even under varying thermal loads.
3Device complexity
If conventional cooling is used, then system simplicity is maintained, but heat transfer coefficient deteriorates leading to temperature rise
Solution Approach 1:
The patent implements a two-phase cooling system where the cooling fluid undergoes cyclic evaporation and condensation. In the evaporator, liquid fluid absorbs heat from the lithographic apparatus components and vaporizes. The vapor then travels to the condenser where it releases heat and condenses back to liquid. This phase transition process provides high heat transfer coefficients, effectively controlling component temperatures without excessive system complexity.
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, thereby improving the operational accuracy and reliability of lithographic apparatuses by increasing heat transfer coefficients and reducing temperature fluctuations.
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
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AI summary
A two-phase thermal conditioning system for thermal conditioning a part (1) of a lithographic apparatus, includes an evaporator (3) 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; a condenser (5) 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; fluid lines (7,8,9) arranged between the evaporator and the condenser to form a circuit in which fluid is able to flow; a pump (14) arranged in the circuit to circulate the fluid in the circuit; an accumulator (16) configured to hold fluid, wherein the accumulator is in fluid communication with the circuit and comprises a heat exchanger (18) to transfer heat from or to fluid inside the accumulator; a temperature sensor (23) configured to provide a measurement signal representative of the temperature of the fluid; and a controller (27) configured to maintain a substantially constant temperature of the fluid inside the circuit by regulating the amount of heat transferred by the heat exchanger from or to fluid inside the accumulator based on the measurement signal.