Supersonic Gas Jet Deflects Tin Nanoparticles in EUV Lithography
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Solution Overview
Problem
In extreme ultraviolet (EUV) lithography, tin nanoparticles generated during the laser-produced plasma process accumulate and cause defects due to high momentum, which existing electromagnetic field deflection methods are insufficient to address effectively without interfering with the lithography apparatus operations.
Innovation Solution
A supersonic gas jet with high-density hydrogen gas is employed at the intermediate focus to deflect tin nanoparticles away from the reticle, either alone or in combination with a low-level electromagnetic field, ensuring minimal interference with the EUV light and apparatus operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If electromagnetic field deflection is used to deflect tin nanoparticles, then nanoparticle deflection is achieved, but interference with lithography apparatus operations occurs
Solution Approach 1:
A gas jet is introduced as an intermediary substance between the electromagnetic field and the tin nanoparticles. The gas flow carries charged particles away from the scanner side through physical transport rather than direct electromagnetic deflection, thereby reducing interference with lithography operations while still achieving nanoparticle removal
Solution Approach 2:
The patent replaces the electromagnetic field-based deflection system with a gas jet-based mechanical transport system. Instead of using electromagnetic forces to deflect nanoparticles, the system uses gas flow to physically carry charged particles away, substituting one mechanism for another with less operational interference
2Illumination intensity
If high-power laser beam is used to generate EUV light, then EUV light emission is improved, but tin debris generation increases
Solution Approach 1:
The patent converts the harmful tin debris generated by the high-power laser into a beneficial charged particle that can be easily removed. By ionizing the tin debris through the laser plasma process, the normally problematic neutral particles become charged, allowing them to be selectively transported away by the gas jet, thus turning the harmful debris into a controllable and removable component
Solution Approach 2:
The system extracts and removes tin debris from the EUV generation process by using the gas jet to carry charged particles away from the scanner side. This separation allows the EUV light generation to continue while the harmful byproduct is continuously removed, preventing accumulation and contamination
3Object-affected harmful factors
If gas jet is used to deflect nanoparticles, then nanoparticle deflection efficiency is improved, but additional system complexity is introduced
Solution Approach 1:
The gas jet system serves multiple functions: it cools the plasma region, transports charged particles away from the scanner, and creates ionization of tin debris. This multi-functionality reduces the need for separate systems and minimizes overall system complexity while achieving effective nanoparticle deflection
Solution Approach 2:
The gas jet system utilizes the existing plasma environment to achieve particle charging and separation. The laser-generated plasma automatically ionizes the tin debris, and the gas flow naturally carries these charged particles away without requiring additional complex control mechanisms, allowing the system to self-regulate the deflection process
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
This approach effectively prevents nearly 100% of tin nanoparticles with momentum less than 3.42×10−14 kgm/s from contaminating the scanner side, significantly reducing defects in semiconductor manufacturing, with minimal additional power and system modifications.
Implementation Method 1
A supersonic gas jet with high-density hydrogen gas is employed at the intermediate focus to deflect tin nanoparticles away from the reticle
Implementation Method 2
EUV lithography employs a laser-produced plasma (LPP), which emits EUV light. The LPP is produced by focusing a high-power laser beam, from a carbon dioxide (CO2) laser and the like, onto small fuel droplet targets of tin (Sn) in order to transition it into a highly-ionized plasma state
Implementation Method 3
existing electromagnetic field deflection methods are insufficient to address effectively
Data Source
AI summary
An extreme ultra violet (EUV) lithography method includes receiving an EUV light by a scanner from an EUV light source, the EUV light passing through an intermediate focus disposed in the scanner and at a junction of the EUV light source and the scanner; directing the EUV light by the scanner to a reticle in the scanner; and deflecting nanoparticles from the EUV light source away from the reticle by generating a gas flow using a gas jet disposed entirely in the scanner and proximate to an interface of the scanner and the intermediate focus such that the gas jet does not block the EUV light.