Buffer Gas Mixture for EUV Light Generation Debris Control
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Solution Overview
Problem
During the generation of extreme-ultraviolet (EUV) light, debris and plasma by-products from the target material deposit on optical devices, damaging them and deteriorating their optical performance.
Innovation Solution
A method and apparatus that introduce a gas mixture into the chamber, comprising a first buffer gas reactive with the target material to form a gaseous product for exhaust and a second buffer gas with higher molecular mass, density, and viscosity to slow down debris, reducing deposition on optical devices and increasing EUV light generation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single buffer gas is introduced to react with target material, then some debris is reduced, but the reaction efficiency is insufficient and debris deposition on optical devices continues
Solution Approach 1:
The patent combines two different buffer gases (first buffer gas and second buffer gas) into a single chamber environment. The first buffer gas reacts with target material to form gaseous products, while the second buffer gas slows down debris through collision. This merging of two different gas functions into one system resolves the contradiction by achieving both high reaction efficiency and effective debris reduction simultaneously.
Solution Approach 2:
The patent uses a composite buffer gas mixture consisting of two gases with different properties. The first buffer gas has high reactivity with the target material, while the second buffer gas has high molecular mass and viscosity for effective debris slowing. This composite approach allows the system to benefit from both gases' strengths, resolving the contradiction between reaction efficiency and debris protection.
2Power
If laser power is increased to generate more EUV light, then EUV output increases, but more debris and plasma by-products are generated that deposit on optical devices
Solution Approach 1:
The patent converts the harmful debris and plasma by-products generated by high-power laser operation into a beneficial situation by introducing buffer gases that actively manage these by-products. The first buffer gas reacts with target material to prevent debris formation, while the second buffer gas captures and slows down any debris that is formed, transforming the harmful effect of high-power operation into a controllable process.
Solution Approach 2:
The buffer gases act as intermediaries between the high-power laser operation and the optical devices. Instead of allowing debris to directly damage the optical devices, the buffer gases intercept and neutralize the debris through chemical reaction and physical slowing, mediating the interaction between the high-power source and the sensitive optical components.
3Object-affected harmful factors
If buffer gas density is increased to slow down debris more effectively, then debris deposition is reduced, but the gas mixture may interfere with EUV light collection
Solution Approach 1:
The patent applies different buffer gases in different spatial and functional zones within the chamber. The first buffer gas is positioned and dosed to optimize reaction with target material at the source, while the second buffer gas is positioned to slow debris in the flight path toward optical devices. This localized application of different gas functions allows effective debris protection without excessive gas density that would interfere with EUV light collection.
Solution Approach 2:
The patent carefully controls the density and flow parameters of the buffer gases to optimize their function. By adjusting the gas flow rates, pressures, and composition ratios, the system achieves sufficient debris slowing without creating a dense gas environment that would absorb or scatter EUV light. This parameter optimization resolves the contradiction between debris protection and light collection efficiency.
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 the deposition of target material and plasma by-products on optical devices, enhancing the optical performance and efficiency of EUV light generation by slowing down debris and increasing the reaction efficiency of the first buffer gas with the target material.
Implementation Method 1
a first buffer gas reactive to the target material and configured to react with the target material to form a gaseous product
Implementation Method 2
a second buffer gas having a larger molecular mass, gas density and viscosity than that of the first buffer gas, and configured to help slow down debris of the target material and/or plasma by-product
Implementation Method 3
a light beam is irradiated on the target material in the chamber to generate plasma and an electromagnetic radiation
Data Source
AI summary
A method for generating an electromagnetic radiation includes the following operations. A target material is introduced in a chamber. A light beam is irradiated on the target material in the chamber to generate plasma and an electromagnetic radiation. The electromagnetic radiation is collected with an optical device. A gas mixture is introduced in the chamber. The gas mixture includes a first buffer gas reactive to the target material, and a second buffer gas to slow down debris of the target material and/or plasma by-product, so as to increase an reaction efficiency of the target material and the first buffer gas, and to reduce deposition of the debris of the target material and/or the plasma by-product on the optical device.