EUV Plasma Source Buffer Gas Control for Debris and Droplet Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing extreme ultraviolet light generation systems face challenges in efficiently managing gas flow rates and debris accumulation during the generation of extreme ultraviolet light, which affects the stability and efficiency of the plasma generation process.
Innovation Solution
The system controls the gas flow rate differently based on whether the target droplet is being irradiated with laser light or not, using a processor to adjust the buffer gas flow rate accordingly, and incorporates partition walls to manage debris and maintain chamber pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a constant high flow rate of buffer gas is supplied during the entire period when the target supply unit outputs droplets, then debris accumulation is reduced, but droplet trajectory deviation increases during non-irradiation periods
Solution Approach 1:
The buffer gas flow rate is dynamically adjusted based on the operational state: a first flow rate is supplied during non-irradiation periods and a second flow rate is supplied during irradiation periods. This dynamic adjustment resolves the contradiction by providing high flow rate only when needed for debris removal while maintaining low flow rate when high flow would cause trajectory deviation.
Solution Approach 2:
The flow rate parameter of the buffer gas is changed according to the irradiation state. The processor controls the flow rate to be a first value during non-irradiation periods and a second value during irradiation periods, optimizing both debris removal and trajectory stability through parameter variation.
2Reliability
If a high flow rate of buffer gas is supplied continuously, then plasma generation stability is improved, but energy consumption and gas usage increase
Solution Approach 1:
The buffer gas supply operates periodically with different flow rates corresponding to the droplet irradiation cycle. High flow rate is applied during irradiation periods when plasma generation occurs, and low flow rate is applied during non-irradiation periods, achieving plasma stability optimization while reducing overall gas consumption.
Solution Approach 2:
The flow rate parameter is optimized by setting different values for different operational phases. The processor controls the flow rate to match the plasma generation requirements, providing sufficient gas flow only when needed for stable plasma generation while minimizing gas consumption during non-operational periods.
3Quantity of substance
If the buffer gas flow rate is reduced during non-irradiation periods, then droplet trajectory stability is improved, but debris accumulation increases
Solution Approach 1:
The system dynamically switches between low flow rate during non-irradiation periods (to maintain trajectory stability) and high flow rate during irradiation periods (to remove debris). This temporal differentiation resolves the contradiction by addressing each requirement at the appropriate time.
Solution Approach 2:
The low flow rate during non-irradiation periods prepares the system for stable droplet delivery by minimizing gas interference with the droplet trajectory, while the subsequent high flow rate during irradiation periods cleans up debris before the next droplet arrives, preventing accumulation issues.
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 enhances the stability and efficiency of extreme ultraviolet light generation by reducing debris accumulation and improving the consistency of the plasma generation process.
Implementation Method 1
a laser produced plasma (LPP) type apparatus using plasma generated by irradiating a target substance with laser light
Implementation Method 2
a chamber in which a target substance supplied to a plasma generation region at an internal space thereof is irradiated with laser light to generate extreme ultraviolet light
Data Source
AI summary
An extreme ultraviolet light generation apparatus includes a chamber in which a target substance supplied to a plasma generation region is irradiated with laser light to generate extreme ultraviolet light, a laser device generating the laser light, a target supply unit supplying a droplet of the target substance toward the plasma generation region, a target collection unit collecting the target substance which has not been irradiated with the laser light, a first gas supply unit supplying a buffer gas into the chamber, and a processor controlling the first gas supply unit so that, in a period of the droplet being output, a first flow rate of the buffer gas to be supplied from the first gas supply unit in at least a part of a first period is smaller than a second flow rate of the buffer gas to be supplied from the first gas supply unit in a second period.