Charged Tin Droplet Deceleration for EUV Splashback Control

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Solution Overview

Problem

The challenge in extreme ultraviolet photolithography is the occurrence of droplet splashback on the collector, which leads to an uneven surface and reduced reflectivity, affecting the effective irradiation of the photolithography target with extreme ultraviolet radiation.

Innovation Solution

A photolithography system utilizing a charge electrode and a counter electrode to impart a net electric charge to droplets, followed by a repulsive electromagnetic force to decelerate them, reducing splashback through a feedback loop controlled by a control system that adjusts voltages based on droplet speed measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If droplets are accelerated to high speed to generate extreme ultraviolet radiation, then productivity is improved, but droplet splashback occurs causing surface unevenness and reduced reflectivity

Engineering Contradiction:

Improveextreme ultraviolet radiation generation efficiencyVSAvoidcollector surface uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

A charge electrode is positioned upstream to impart a net electric charge to droplets before they reach the collector. This preliminary charging enables subsequent electromagnetic deceleration and splashback prevention, countering the harmful effects before they occur on the collector surface

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

An electric field is introduced as an intermediary between the droplet generator and collector. The charge electrode and counter electrode create an electromagnetic field that mediates droplet deceleration and trajectory control, preventing direct high-speed impact on the collector

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If droplets are accelerated to high speed to generate extreme ultraviolet radiation, then productivity is improved, but reflectivity of the collector is reduced

Engineering Contradiction:

Improveextreme ultraviolet radiation generation efficiencyVSAvoidcollector reflectivity

Core Design Contradiction:

ProductivityVSIllumination intensity

Solution Approach 1:

The charge electrode imparts electric charge to droplets in advance, enabling the electromagnetic field to decelerate them before impact. This prevents surface damage that would reduce reflectivity, maintaining illumination intensity for photolithography

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

A feedback loop monitors droplet speed and adjusts the voltage applied to the counter electrode accordingly. This closed-loop control ensures optimal deceleration to prevent splashback and maintain collector reflectivity while preserving productivity

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If electromagnetic deceleration is applied to reduce splashback, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improvedroplet trajectory controlVSAvoidelectrode and control system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical deceleration mechanisms with an electromagnetic field-based system. Charge and counter electrodes create an electromagnetic environment that naturally decelerates charged droplets, achieving precise trajectory control without complex mechanical components

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 system effectively reduces droplet splashback, maintaining a stable trajectory and reflectivity of extreme ultraviolet radiation towards the photolithography target, ensuring consistent and efficient photolithography processes.

Implementation Method 1

A charge electrode and a counter electrode are positioned in a droplet receiver. A voltage is applied to the charge electrode to impart a net electric charge to the droplets

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

A voltage is applied to the counter electrode to generate a repulsive electromagnetic force to decelerate the droplets

Methodology Applied

Scientific EffectRepulsive electromagnetic force: Lorentz Force

Implementation Method 3

extreme ultraviolet light is typically produced by irradiating droplets of selected materials with a laser beam. The energy from the laser causes the droplets to enter a plasma state. In the plasma state, the droplets emit extreme ultraviolet light

Methodology Applied

Scientific EffectLaser irradiation: Laser

Implementation Method 4

The collector reflects the extreme ultraviolet light onto the photolithography target

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS12411419B2Droplet splash control for extreme ultraviolet photolithography

Publication Date: 2025.09.09 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A photolithography system utilizes tin droplets to generate extreme ultraviolet radiation for photolithography. The photolithography system irradiates the droplets with a laser. The droplets become energized and emit extreme ultraviolet radiation. A collector reflects the extreme ultraviolet radiation toward a photolithography target. The photolithography system reduces splashback of the tin droplets onto the receiver by generating a net electric charge within the droplets using a charge electrode and decelerating the droplets by applying an electric field with a counter electrode.