Dual-Pulse Laser EUV Light Source for Lithography
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Solution Overview
Problem
Existing methods for generating extreme ultraviolet (EUV) light in lithography processes have limitations in power conversion efficiency, which affects the performance and complexity of semiconductor integrated circuit manufacturing.
Innovation Solution
A lithography exposure system utilizing a dual-pulse laser-produced plasma mechanism with a target fuel generator that produces droplets of tin or eutectic alloy, which are then irradiated by pre-pulse and main pulse lasers to enhance EUV light emission, along with a selection mechanism for nozzle assemblies to maintain stable fuel supply and minimize contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If laser-produced plasma is used to generate EUV light, then EUV radiation can be produced for lithography exposure, but power conversion efficiency from input energy for ionization is insufficient
Solution Approach 1:
A pre-pulse laser is applied before the main pulse laser to pre-ionize the tin droplet target. This preliminary action creates a plasma channel that guides the main pulse energy more efficiently into the target, reducing energy loss and improving overall power conversion efficiency from input energy to EUV radiation output.
Solution Approach 2:
The invention optimizes multiple parameters including laser pulse duration, pulse separation time, droplet size, and target composition (tin or eutectic alloy). By carefully controlling these parameters, the system maximizes EUV photon yield per unit of input energy, thereby improving power conversion efficiency.
2Reliability
If multiple nozzle assemblies are used to supply target fuel, then stable fuel supply can be maintained, but device complexity increases
Solution Approach 1:
The fuel supply system is divided into multiple independent nozzle assemblies, each capable of supplying target fuel droplets. This segmentation allows individual nozzles to be monitored and replaced independently, maintaining stable overall fuel supply while managing complexity through modular design.
Solution Approach 2:
Nozzle assemblies are designed with replaceable components that can be discarded after a certain number of uses or when contamination occurs. Quick-change mechanisms allow rapid replacement of worn nozzles, maintaining reliable fuel supply without requiring complex maintenance systems.
3Productivity
If continuous operation is maintained to increase productivity, then wafer production throughput increases, but contamination accumulates requiring maintenance downtime
Solution Approach 1:
Multiple nozzle assemblies are operated in a continuous rotation sequence, ensuring that while one nozzle is in use, others are ready for immediate replacement. This continuity eliminates idle time between nozzle changes and maintains uninterrupted wafer production, maximizing throughput while managing contamination through systematic rotation.
Solution Approach 2:
The system incorporates automated monitoring and quick-change mechanisms that allow nozzle replacement to be performed rapidly with minimal intervention. Contaminated nozzles are automatically detected and replaced by the system itself, reducing maintenance downtime and maintaining high productivity.
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 system improves EUV light generation efficiency, increases product yield, and reduces downtime for maintenance by ensuring stable fuel supply and efficient plasma formation, thereby enhancing semiconductor wafer production throughput.
Implementation Method 1
A pre-pulse laser is applied to the tin droplet before application of the main pulse laser
Implementation Method 2
focusing a high-power laser onto small fuel droplet targets to form highly ionized plasma that emits EUV radiation
Implementation Method 3
form highly ionized plasma that emits EUV radiation with a peak of maximum emission at 13.5 nm
Implementation Method 4
irradiated by pre-pulse and main pulse lasers to enhance EUV light emission
Data Source
AI summary
A method for generating a radiation light in a lithography exposure system is provided. The method includes connecting a first nozzle assembly coupled to a support to an outlet of a storage member that receives a target fuel inside. The method further includes guiding the target fuel flowing through the first nozzle assembly and supplying a droplet of the target fuel into an excitation zone via the first nozzle assembly. The method also includes moving the support to connect a second nozzle assembly coupled to the support with the outlet. In addition, the method includes guiding the target fuel flowing through the second nozzle assembly and supplying a droplet of the target fuel into the excitation zone via the second nozzle assembly. The method further includes irradiating the droplet of the target fuel in the excitation zone with a laser pulse.