Charged Tin Droplet Deceleration to Prevent EUV Collector Splashback

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Solution Overview

Problem

In extreme ultraviolet photolithography, splashback from high-velocity droplets onto the collector can result in an uneven surface, reducing the effectiveness of extreme ultraviolet radiation reflection and potentially making the collector nonreflective, which affects the precision and efficiency of feature formation on integrated circuit dies.

Innovation Solution

A photolithography system that utilizes a charge electrode and a counter electrode to impart a net electric charge to droplets, reducing their velocity through a repulsive electromagnetic force, thereby minimizing splashback. The system includes a control system that adjusts voltages applied to these electrodes based on droplet speed measurements to achieve optimal deceleration and prevent droplet impact on the collector.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If droplets are projected at high velocity toward the collector, then extreme ultraviolet light generation efficiency is improved, but droplet splashback occurs causing collector surface unevenness and reduced reflectivity

Engineering Contradiction:

Improveextreme ultraviolet light generation efficiencyVSAvoidcollector surface uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

A charge electrode is introduced as an intermediary component between the droplet source and the collector. This electrode imparts electric charge to the droplets, enabling electromagnetic interaction that decelerates them before they reach the collector, thereby preventing splashback while maintaining high velocity for efficient extreme ultraviolet light generation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The velocity parameter of the droplets is dynamically adjusted by applying electromagnetic forces through the charge electrode. By controlling the electric field strength, the system optimizes droplet speed to balance between generation efficiency and splashback prevention, ensuring consistent collector surface quality

Inventive Principle:

Principle #35Parameter changes

2Productivity

If droplet velocity is increased to enhance extreme ultraviolet radiation output, then photolithography productivity improves, but droplet impact causes collector surface irregularities

Engineering Contradiction:

Improvephotolithography outputVSAvoiddroplet splashback

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The charge electrode applies a repulsive electromagnetic force to the droplets before they reach the collector, creating a preliminary counter-action that reduces droplet velocity. This prevents the harmful splashback effect while preserving the high velocity needed for efficient extreme ultraviolet radiation generation and photolithography productivity

Inventive Principle:

Principle #9Preliminary anti-action

3Manufacturing precision

If droplets are decelerated using electromagnetic forces, then collector surface quality is maintained, but system complexity increases due to additional electrodes and control mechanisms

Engineering Contradiction:

Improvecollector surface smoothnessVSAvoidelectrode control system

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The charge electrode serves multiple functions: it imparts electric charge to the droplets, decelerates them through electromagnetic repulsion, and prevents splashback on the collector. This multi-functionality reduces the need for separate components, thereby minimizing the increase in system complexity while achieving improved collector surface quality

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution effectively reduces splashback, maintaining a smooth collector surface and ensuring consistent extreme ultraviolet radiation reflection, thereby enhancing the precision and efficiency of the photolithography process by controlling droplet speed and preventing surface irregularities.

Implementation Method 1

A photolithography system that utilizes a charge electrode and a counter electrode to impart a net electric charge to droplets, reducing their velocity through a repulsive electromagnetic force

Methodology Applied

Scientific EffectElectromagnetic repulsion: Lorentz Force

Implementation Method 2

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 ablation: Laser Ablation

Data Source

PatentUS11940738B2Droplet splash control for extreme ultra violet photolithography

Publication Date: 2024.03.26 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.