Stabilizing EUV Light Power via Dual-Beam Target Modification
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Solution Overview
Problem
Current methods for producing extreme ultraviolet (EUV) light in plasma sources face challenges in stabilizing the power of EUV light emitted, which affects the efficiency and consistency of the EUV light used in photolithography processes.
Innovation Solution
A method involving a target material that emits EUV light when converted to plasma, where a first beam of radiation modifies the target's geometric distribution, and a second beam converts it into plasma, with controlled radiant exposure to stabilize the EUV light power by adjusting the energy and area of the first beam's interaction with the target.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single beam of radiation is used to produce plasma from target material, then the process is simple, but the EUV light power cannot be stabilized
Solution Approach 1:
The radiation beam is divided into two separate beams: a first beam that modifies the geometric distribution of the target material and a second beam that converts the modified target to plasma. This segmentation allows independent optimization of target preparation and plasma generation, enabling stable EUV light power output.
Solution Approach 2:
The first beam of radiation is applied to the target material before the second beam converts it to plasma. This preliminary action modifies the geometric distribution of the target material, creating optimal conditions for subsequent plasma generation and ensuring stable EUV light emission.
2Power
If the target material is irradiated with high energy to increase EUV output, then the EUV light power increases, but the expansion rate becomes unstable
Solution Approach 1:
The radiant exposure of the first beam of radiation is controlled within a specific range (e.g., 1-10 J/cm²) to optimize the expansion rate of the target material. By adjusting parameters such as beam energy, pulse duration, and spatial distribution, the method achieves both high EUV light power and stable expansion rate.
Solution Approach 2:
The method dynamically controls the interaction between the first beam and target material by adjusting the radiant exposure in real-time. This dynamic control ensures that the expansion rate remains within the optimal range, maintaining both high power output and stability.
3Productivity
If the radiant exposure is increased to improve conversion efficiency, then more target material is converted to plasma, but the geometric distribution control becomes difficult
Solution Approach 1:
The first beam of radiation is applied in controlled pulses with specific timing and duration. This periodic action allows precise control over the geometric distribution modification process, enabling high conversion efficiency while maintaining accurate geometric control of the target material.
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 increases the conversion efficiency of EUV light production by maintaining the expansion rate of the modified target within a predetermined range, enhancing the usable EUV light output for applications like photolithography.
Implementation Method 1
directing a first beam of radiation toward the target material to deliver energy to the target material to modify a geometric distribution of the target material
Implementation Method 2
directing a second beam of radiation toward the modified target, the second beam of radiation converting at least part of the modified target to plasma that emits EUV light
Implementation Method 3
converting a material that has an element, for example, xenon, lithium, or tin, with an emission line in the EUV range in a plasma state
Data Source
AI summary
A method includes providing a target material that includes a component that emits extreme ultraviolet (EUV) light when converted to plasma; directing a first beam of radiation toward the target material to deliver energy to the target material to modify a geometric distribution of the target material to form a modified target; directing a second beam of radiation toward the modified target, the second beam of radiation converting at least part of the modified target to plasma that emits EUV light; controlling a radiant exposure delivered to the target material from the first beam of radiation to within a predetermined range of radiant exposures; and stabilizing a power of the EUV light emitted from the plasma by controlling the radiant exposure delivered to the target material from the first beam of radiation to within the predetermined range of radiant exposures.