EUV Radiation Source Buffer Gas Conduit Placement
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Solution Overview
Problem
Despite the use of buffer gases to mitigate damage from plasma debris in extreme ultraviolet radiation sources, some particles still reach and damage the collector mirror due to the inefficiency of the buffer gas distribution, which is heated and pushed away slowly, allowing debris to interact with the mirror before new buffer gas can take its place.
Innovation Solution
A conduit is positioned adjacent to the interaction point in the radiation source to deliver unheated buffer gas directly, ensuring a denser and more effective buffer gas presence around the interaction point, reducing particle interactions with the collector mirror and extending its lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If buffer gas is provided in the vicinity of the plasma to slow down particles, then damage to the collector mirror is reduced, but the buffer gas is heated and pushed away slowly, allowing some particles to still reach and damage the mirror
Solution Approach 1:
The invention introduces fresh buffer gas into the chamber before the plasma is generated. This preliminary action ensures that when the plasma is created, there is already a sufficient supply of cold buffer gas present to immediately slow down and neutralize particles, preventing them from reaching the collector mirror. This resolves the contradiction by preparing the protective buffer gas atmosphere in advance, eliminating the delay associated with heating and pushing away buffer gas after plasma generation.
2Object-affected harmful factors
If buffer gas is used to collide with and slow down particles, then some particles are prevented from reaching the collector mirror, but the buffer gas becomes heated and less effective over time
Solution Approach 1:
The invention employs periodic replenishment of buffer gas in the chamber. After the buffer gas has been heated by plasma generation and particle collisions, fresh buffer gas is introduced to replace the heated gas. This periodic action maintains a supply of cold, effective buffer gas to continuously protect the collector mirror, resolving the contradiction between the buffer gas's protective function and its temperature increase over time.
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 direct delivery of unheated buffer gas effectively protects the collector mirror from plasma debris, increasing its operational lifetime by ensuring continuous, high-density buffer gas interaction with particles, thereby reducing damage and extending maintenance intervals.
Implementation Method 1
A laser beam is directed onto a tin droplet in order to generate plasma
Implementation Method 2
The plasma emits extreme ultraviolet radiation (or beyond EUV radiation)
Implementation Method 3
The particles produced by the plasma collide with molecules of the buffer gas, and thereby lose energy
Implementation Method 4
plural magnets that generate a magnetic field within the chamber so as to trap at least the charged particles ionized by the X-ray source
Implementation Method 5
an X-ray source that ionizes neutral particles included in particles emitted from the plasma into charged particles
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
A radiation source comprising a chamber (1) and a supply of a plasma generating substance, the source having an interaction point (13) at which the plasma generating substance introduced into the chamber may interact with a laser beam (7) and thereby produce a radiation emitting plasma, wherein the source further comprises a conduit (11) arranged to deliver a buffer gas into the chamber, the conduit having an outlet (12) which is adjacent to the interaction point.