EUV Droplet Generator Nozzle Thermal Segmentation
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Solution Overview
Problem
Current EUV light generation systems face challenges in efficiently supplying and recovering target material, particularly due to labor-intensive reloading processes and downtime issues, as well as difficulties in maintaining nozzle integrity and removing unvaporized material without breaking the vacuum.
Innovation Solution
A target material handling system that includes a reservoir, conduit with temperature maintenance capabilities, and a heat actuated valve system to maintain the nozzle above the melting temperature of the target material, allowing for continuous operation and efficient transfer of target material, along with a recovery system for unvaporized material within the vacuum chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the droplet generator is cooled down below the melting point of the target material for reloading, then the target material can be replenished, but the nozzle may solidify and form contaminant particles that clog the nozzle
Solution Approach 1:
The droplet generator is divided into two separate sections: a nozzle section that remains heated above the melting point to maintain reliable operation, and a reservoir section that can be cooled down for reloading. This segmentation allows independent temperature control of each section, resolving the contradiction between reloading capability and nozzle reliability.
Solution Approach 2:
A thermal isolation mechanism (such as a thermally insulating barrier or movable partition) is introduced between the nozzle section and reservoir section. This intermediary prevents heat transfer from the heated nozzle to the reservoir, enabling the reservoir to be cooled for reloading while the nozzle maintains its operating temperature.
2Quantity of substance
If the droplet generator is taken offline for reloading, then target material can be supplied, but significant downtime occurs
Solution Approach 1:
By segmenting the droplet generator into a continuously operating nozzle section and a separately reloadable reservoir section, the system enables reloading operations without taking the entire generator offline. The nozzle section maintains operation while the reservoir is replenished, significantly reducing downtime.
Solution Approach 2:
The reservoir can be prepared and cooled down for reloading in advance while the nozzle section continues operating. This preliminary preparation of the reservoir section allows for rapid reloading without interrupting the droplet generation process.
3Ease of operation
If the nozzle is cooled down for material replenishment, then loading becomes easier, but restart becomes difficult due to solidified material and particle formation
Solution Approach 1:
Separating the nozzle from the reservoir allows the reservoir to be cooled and opened for easy material loading, while the nozzle remains heated and maintains its restart capability. The segmented design ensures that cooling for loading does not affect the nozzle's operational state.
Solution Approach 2:
A thermal barrier or isolation mechanism prevents heat transfer between the heated nozzle and the cooled reservoir. This intermediary enables the reservoir to be cooled down for easy material loading while the nozzle maintains its temperature to ensure easy restart capability.
4Productivity
If the entire droplet generator is heated to maintain target material above melting point, then continuous operation is enabled, but energy consumption increases
Solution Approach 1:
Dividing the droplet generator into a heated nozzle section and a non-heated (or separately cooled) reservoir section reduces the total volume requiring continuous heating. Only the nozzle section needs to maintain high temperature for continuous operation, while the reservoir can be at lower temperature, significantly reducing energy consumption.
Solution Approach 2:
Heating is applied locally only to the nozzle section where it is critically needed for maintaining target material in liquid form, rather than heating the entire droplet generator. This localized heating approach maintains continuous operation capability while minimizing energy consumption.
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 solution reduces downtime, ensures reliable restarts of the droplet generator, and facilitates efficient removal of unvaporized target material without compromising the vacuum, enhancing the operational efficiency and longevity of the EUV light generation system.
Implementation Method 1
a heater arranged to be capable of maintaining the nozzle and the second portion at a first temperature not less than a melting temperature of the target material
Implementation Method 2
the conduit is adapted to be able to maintain a temperature differential such that the second portion may be maintained at the first temperature when a temperature of the first portion is at an ambient temperature substantially below the first temperature
Implementation Method 3
maintaining the nozzle and the second portion at a first temperature not less than a melting temperature of the target material
Data Source
AI summary
An EUV light source target material handling system is disclosed which may comprise a droplet generator having a target material reservoir in which the target material may be replenished while a nozzle portion of the droplet generator is maintained at temperature. Also disclosed is a system for selectively draining spent target material.