EUV Metal Droplet Catcher Baffle System

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Solution Overview

Problem

In extreme ultraviolet (EUV) photolithography, the contamination of the EUV chamber by metal droplets leads to inefficient plasma formation and reduced quality of EUV light, as the metal droplets can splash back and contaminate the collector mirror, necessitating an effective metal droplet catcher to prevent this issue.

Innovation Solution

A metal droplet catcher with a baffle system is introduced, featuring baffles arranged along its length and making an acute angle with the inner surface to impede the flow of splashed molten metal while allowing incoming metal droplets to enter, thereby preventing contamination and improving EUV light quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If an open container metal catcher is used to collect metal droplets, then metal droplet collection is achieved, but metal droplets are evaporated or splashed backward causing chamber contamination

Engineering Contradiction:

Improvemetal droplet collection efficiencyVSAvoidchamber contamination

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The metal catcher is divided into multiple sections: a collection section for receiving metal droplets, a baffle section with multiple baffles arranged in sequence, and a discharge section. This segmentation allows the droplets to be collected and then guided through the baffle section where they are redirected downward, preventing backward splash and evaporation that would cause contamination.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The baffle section acts as an intermediary element between the collection section and the discharge section. The baffles redirect the metal droplets from a horizontal flow direction to a downward flow direction, serving as a mediator that prevents the droplets from splashing backward into the chamber while maintaining efficient collection and discharge.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of repair

If metal droplets are collected in an open container, then droplet recycling is enabled, but plasma formation control is compromised due to back-splash

Engineering Contradiction:

Improvemetal droplet recyclingVSAvoidplasma formation control

Core Design Contradiction:

Ease of repairVSReliability

Solution Approach 1:

The metal catcher is segmented into a collection section, baffle section, and discharge section. This allows droplets to be collected for recycling while the baffle section redirects them downward to prevent back-splash into the plasma formation region, thus maintaining reliable plasma formation control.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of allowing metal droplets to flow backward or evaporate in the conventional open container design, the invention inverts the flow direction by using baffles to redirect the droplets downward toward the discharge section. This inversion prevents back-splash contamination and maintains plasma formation control while still enabling droplet recycling.

Inventive Principle:

Principle #13The other way round (Inversion)

3Object-affected harmful factors

If a baffle system is added to prevent metal droplet splash, then chamber contamination is reduced, but device complexity increases

Engineering Contradiction:

Improvechamber contaminationVSAvoidmetal catcher structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The baffle system is segmented into multiple baffles arranged in sequence within the baffle section, each baffle contributing to redirecting the metal droplets downward. This segmented approach effectively prevents contamination while maintaining a manageable structural complexity that can be integrated into the existing metal catcher design.

Inventive Principle:

Principle #1Segmentation

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 baffle system effectively collects and contains metal droplets, reducing contamination and enhancing the quality of EUV light produced, thereby improving the efficiency and reliability of the EUV photolithography process.

Implementation Method 1

baffles arranged along its length and making an acute angle with the inner surface to impede the flow of splashed molten metal

Methodology Applied

Scientific EffectFluid flow impediment:

Implementation Method 2

the laser beam hits a first target (i.e. a metal droplet stream) to form plasma which emits EUV light rays

Methodology Applied

Scientific EffectPlasma formation: Plasma

Implementation Method 3

plasma which emits EUV light rays

Methodology Applied

Scientific EffectLight emission from plasma: Luminescence

Implementation Method 4

the EUV light rays travelling in a direction opposite to the path toward the target substrate would be wasted if not collected and re-directed towards the intended target. The collector mirror is thus required to collect and re-direct the EUV light rays toward the target substrate and focus the collected light rays

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS10871719B2EUV metal droplet catchers

Publication Date: 2020.12.22 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A droplet catcher includes a tube main body and baffles arranged along a length direction of the tube main body.