EUV Power Supply RF Termination for Standing Wave Suppression

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Solution Overview

Problem

Current power supply systems for extreme ultraviolet (EUV) radiation sources in lithographic apparatuses suffer from significant RF energy reflection, leading to inefficiencies and limitations in operating frequency due to standing waves on coaxial cables, resulting in wasted energy and potential electromagnetic safety risks.

Innovation Solution

The implementation of RF terminations, such as a parallel resistor-inductor network, and a balanced power supply with RF terminations at strategic points in the transmission line to dissipate reflected RF signals and ensure balanced voltage distribution, effectively reducing ringing currents and enhancing energy utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional power supply systems without RF terminations are used, then the system structure is simpler, but RF energy reflection causes standing waves, energy wastage, and electromagnetic safety risks

Engineering Contradiction:
ImproveRF energy reflection lossVSAvoidpower supply system structure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent introduces RF termination components (resistors and inductors) as intermediary elements in the power supply system. These terminations act as mediators that absorb and dissipate reflected RF energy, preventing standing waves and energy loss without fundamentally redesigning the entire power supply architecture

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts and addresses the specific problem of RF reflection by adding separate termination components (RF resistors and inductors) to the power supply circuit. This allows the main power supply structure to remain relatively simple while the extracted RF termination function handles the energy reflection issue

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If RF terminations are added to reduce RF reflection, then energy utilization improves, but the device complexity increases

Engineering Contradiction:
Improveoperating frequencyVSAvoidpower supply circuit structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent modifies the electrical parameters of the power supply system by introducing specific RF termination components with defined impedance values. These parameter changes (adding resistors and inductors with specific values) enable the system to operate at higher frequencies by suppressing parasitic resonances, while the component values are optimized to minimize overall system complexity

Inventive Principle:
Principle #35Parameter changes

3Reliability

If RF terminations are implemented, then energy wastage is reduced, but the system requires additional components increasing complexity

Engineering Contradiction:
Improveelectromagnetic safetyVSAvoidtransmission line structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent converts the harmful reflected RF energy into a beneficial effect by using RF termination components to deliberately absorb and dissipate this energy. The reflected RF signals, which would normally cause standing waves and safety issues, are now channeled through the termination components where they are safely converted to heat, improving electromagnetic safety while adding minimal complexity to the transmission line structure

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 suppresses parasitic resonances, increases the operating frequency of EUV sources, reduces energy wastage, and minimizes electromagnetic interference, thereby improving the efficiency and safety of EUV radiation generation.

Implementation Method 1

one or more RF terminations provided on one or more of an input end of the transmission line or an output end of the transmission line, the one or more RF terminations terminating the transmission line to reduce reflection of RF energy

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the matching network comprises a resistor and an inductor connected in parallel

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Implementation Method 3

the matching network comprises a resistor and an inductor connected in parallel

Methodology Applied
Scientific EffectInductance: Inductor

Data Source

PatentEP2732558B1Power supply for a discharge produced plasma EUV source
Publication Date: 2019.03.06 USHIO INC
  • EP2732558B1 patent drawingFigure 1~2
  • EP2732558B1 patent drawingFigure 3
  • EP2732558B1 patent drawingFigure 4A

AI summary

A power supply (310) for providing HV power to a lithography illumination source (350) comprising a HV power source arranged to provide the HV power, a HV power transmission line arranged (370) to transmit the HV energy from the HV power source and one or more RF terminations (360) provided on one or more of an input end of the transmission line or an output end of the transmission line. The one or more RF terminations terminate the transmission line to reduce reflection of RF energy at the end of the transmission line.