Excimer Laser Composite Cavity for Narrow Line-Width and High Power

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Solution Overview

Problem

Conventional excimer laser devices struggle to achieve both narrow line-width and high power output simultaneously, as existing solutions either sacrifice power for line-width narrowing or vice versa, which is crucial for advanced photolithography applications.

Innovation Solution

An excimer laser composite cavity is designed, comprising a laser discharge cavity, a line-width narrowing module, and a laser amplification module, with a beam splitter and grating configuration that narrows the line-width while amplifying power, using a combination of prisms and gratings to control the spectrum and central wavelength, ensuring efficient output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional combination of a laser and a line-width narrowing module is used, then the line-width is narrowed, but the power output is sacrificed

Engineering Contradiction:
Improveline-widthVSAvoidpower output
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The laser cavity is divided into two independent cavities: a first cavity configured for line-width narrowing and a second cavity configured for power amplification. This segmentation allows each cavity to optimize for its specific function without compromising the other, resolving the contradiction between narrow line-width and high power output

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first laser cavity (line-width narrowing) and second laser cavity (power amplification) are nested within a composite cavity structure, where the output of one cavity serves as input to the other. This nested arrangement enables sequential processing: first narrowing the line-width, then amplifying the power, achieving both objectives simultaneously

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If the power output and line-width of a laser device are adjusted to meet special requirements, then the laser can be suitable for photolithography, but the device complexity increases

Engineering Contradiction:
Improvesuitability for photolithographyVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The complex requirement for simultaneous narrow line-width and high power is segmented into two separate functional cavities, each optimized for one aspect. This segmentation makes the overall system more manageable and easier to control than a single complex cavity attempting to achieve both goals

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The composite cavity structure serves multiple functions: it provides both line-width narrowing and power amplification, and can be configured for different photolithography requirements by adjusting the parameters of the individual cavities. This multi-functionality achieves adaptability without proportionally increasing complexity

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 enables the excimer laser to produce a laser beam with both narrow line-width and high power, suitable for photolithography, by effectively balancing line-width narrowing and power amplification, enhancing its spectral purity and output stability.

Implementation Method 1

the grating is configured to receive the expanded laser beam emitted from the single prism or prism group at an incident angle equivalent to a blazing angle of the grating, so that the laser beam incident on a surface of the grating is dispersed

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

a laser beam with a wavelength meeting a blazing condition of the grating is reflected back along an opposite direction of its incident path

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

refract and expand a remaining part of the laser beam

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 4

an etalon configured to narrow down the line-width of the laser beam incident thereon and transmit laser beam with a particular central wavelength

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 5

a reflector configured to receive the part of the laser beam reflected by the single prism or prism group, and reflect the part of the laser beam back to the laser discharge cavity

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2937954B1Excimer laser combination cavity
Publication Date: 2020.07.22 RAINBOW SOURCE LASER RSLASER
  • EP2937954B1 patent drawingFigure 1
  • EP2937954B1 patent drawingFigure 2
  • EP2937954B1 patent drawingFigure 3

AI summary

Disclosed is an excimer laser composite cavity, comprising a laser discharge cavity, a laser output module, a line-width narrowing module, and a laser amplification module. The laser discharge cavity contains work gas for generating laser when it is activated by an excitation source. The laser discharge cavity, the laser output module, and the line-width narrowing module constitute a line-width narrowing cavity configured to narrow down a line-width of the laser generated by the work gas. The laser discharge cavity, the laser output module, and the laser amplification module constitute an amplification cavity configured to amplify power of the laser with the line-width having been narrowed down by the line-width narrowing cavity.