Target Supply Unit Induction Heating for EUV
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Solution Overview
Problem
Current semiconductor production processes face challenges in achieving microfabrication with feature sizes of 32 nm or less, requiring efficient systems for generating extreme ultraviolet (EUV) light, particularly in heating and maintaining the target material at or above its melting point for EUV light generation.
Innovation Solution
A target supply unit with a reservoir and a heater, such as a resistive element, flexible heater, infrared heater, or induction coil, is used to directly heat and maintain the target material at or above its melting point, improving efficiency compared to indirect heating methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If indirect heating methods are used to heat the target material, then the heating process is simpler to implement, but the heating efficiency is low and the target material cannot be rapidly brought to melting point
Solution Approach 1:
The patent replaces indirect thermal conduction heating with direct electromagnetic field heating (induction heating). The induction coil generates a magnetic field that directly induces eddy currents in the target material, converting electromagnetic energy directly into heat within the target material itself, thereby achieving rapid and efficient heating without requiring thermal conduction through intermediate media
Solution Approach 2:
The patent introduces an induction coil as an intermediary that generates a magnetic field to couple energy directly to the target material. This magnetic field acts as the mediator that transfers energy from the power source to the target material, enabling efficient energy transfer and rapid heating while maintaining system modularity
2Productivity
If the target material is heated rapidly to melting point, then the EUV light generation efficiency is improved, but the temperature control becomes more difficult
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the temperature of the target material and adjusts the power supplied to the induction coil accordingly. This closed-loop control enables rapid heating to melting point while maintaining stable temperature control during operation, ensuring consistent EUV light generation
Solution Approach 2:
The patent employs dynamic power adjustment where the heating power is varied in real-time based on operational requirements. During the heating phase, high power is applied to rapidly reach melting point; during the maintenance phase, power is adjusted to sustain the required temperature, enabling both rapid heating and stable temperature control
3Reliability
If the target material is maintained in molten state, then consistent plasma production is achieved, but energy consumption increases
Solution Approach 1:
The patent employs periodic pulsed heating where the induction coil is activated in cycles rather than continuously. The heating power is applied periodically to maintain the target material in molten state, reducing overall energy consumption while ensuring consistent plasma production during the active phases of the cycle
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 approach allows for efficient heating and retention of the target material in a molten state, enhancing the EUV light generation process by ensuring consistent and high-quality plasma production for microfabrication.
Implementation Method 1
a heater provided inside the reservoir for heating the target material stored in the reservoir
Implementation Method 2
an infrared heater provided outside the reservoir for heating the target material stored in the reservoir by radiated heat
Implementation Method 3
an induction heater provided outside the reservoir for heating the target material stored in the reservoir by induction heating
Data Source
AI summary
A target supply unit may include: a reservoir for storing a target material; a heater provided inside the reservoir for heating the target material stored in the reservoir; a heater power supply for supplying current to the heater; and a target outlet for outputting the target material stored inside the reservoir.