Packed-Bed Fluoride Dust Filter for Laser Chamber Flow Control

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Solution Overview

Problem

The degradation of electrodes in a master oscillator power amplifier (MOPA) due to metal fluoride dust leads to optical damage and reduced laser performance, necessitating improved dust trapping and flow control in the gas discharge medium.

Innovation Solution

A metal fluoride trap incorporating a packed-bed filter with spherical beads made of fluoride corrosion-resistant materials, configured to absorb and trap dust through mechanical and chemical interactions, and an electrostatic precipitator to enhance dust removal and control flow distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal fluoride trap is used to trap metal fluoride dust, then dust trapping capacity is improved, but device complexity increases

Engineering Contradiction:

Improvedust trapping capacityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The packed-bed filter is disposed around the electrostatic precipitator in a nested configuration, where the filter contains beads arranged in a cylindrical structure surrounding the precipitator. This nesting approach allows both dust trapping mechanisms to occupy the same spatial envelope, increasing dust trapping capacity without proportionally increasing the overall device footprint or complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The packed-bed filter utilizes a bed of porous beads (such as porous glass or ceramic beads) that provide extensive surface area for dust adsorption. The porous structure allows gas to flow through while capturing metal fluoride dust particles, enhancing trapping capacity through the high surface area-to-volume ratio of the porous material.

Inventive Principle:

Principle #31Porous materials

2Reliability

If the packed-bed filter uses a large total surface area to control flow rate, then flow distribution is improved, but pressure drop increases

Engineering Contradiction:

Improveflow distributionVSAvoidpressure drop

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The packed-bed filter employs beads with specifically engineered local properties - uniform size distribution, controlled porosity, and consistent surface chemistry - to achieve homogeneous flow distribution throughout the filter bed. This local quality control ensures that gas flows evenly through all regions of the filter, preventing channeling and improving overall flow distribution while managing pressure drop.

Inventive Principle:

Principle #3Local quality

3Duration of action of stationary object

If fluoride corrosion resistant materials are used for the beads, then durability is improved, but manufacturing cost increases

Engineering Contradiction:

Improveservice lifetimeVSAvoidmanufacturing cost

Core Design Contradiction:

Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The invention employs porous beads made from fluoride-corrosion-resistant materials such as porous glass or ceramic. These materials inherently resist degradation from exposure to fluorinated gases, significantly extending the service lifetime of the filter. The porous structure provides the necessary surface area for dust capture while maintaining structural integrity in the corrosive environment, balancing durability with manufacturability.

Inventive Principle:

Principle #31Porous materials

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 packed-bed filter increases dust trapping capacity, optimizes flow distribution, facilitates efficient cleaning, and extends the service lifetime of the MOPA by reducing dust accumulation on optical windows and improving laser performance.

Implementation Method 1

chemical interaction with the surfaces of the beads (e.g., adsorption)

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

mechanical trapping of the dust particles in the interstitial spaces between the beads

Methodology Applied

Scientific EffectMechanical trapping: Filter (physical)

Implementation Method 3

The metal fluoride trap includes an electrostatic precipitator and a packed-bed filter disposed around the electrostatic precipitator

Methodology Applied

Scientific EffectElectrostatic precipitation: Electrostatic Deposition

Data Source

PatentUS12597753B2Packed-bed filter for metal fluoride dust trapping in laser discharge chambers

Publication Date: 2026.04.07 CYMER INC

AI summary

A light source apparatus (200) includes a gas discharge stage (210) and a metal fluoride trap (300). The gas discharge stage includes an optical amplifier (206) and a set of optical elements (250, 260). The optical amplifier includes a chamber (211) configured to hold a gas discharge medium (213), the gas discharge medium outputting a light beam. The set of optical elements is configured to form an optical resonator around the optical amplifier. The metal fluoride trap is configured to trap metal fluoride dust generated from the gas discharge stage. The metal fluoride trap includes an electrostatic precipitator (320) and a packed-bed filter (400, 402, 404) disposed around the electrostatic precipitator. The packed-bed filter includes a plurality of beads configured (406, 408) to absorb metal fluoride dust (208).