Radiation Source Thermal Load Applicator for Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current plasma-based radiation sources, such as xenon arc-discharge lamps, have a short lifetime and high thermal stress issues, which limit their brightness and longevity in applications like lithographic metrology, where increased spectral bandwidth and lower transmittance are required without increasing measurement time.
Innovation Solution
A radiation source apparatus with a container for generating plasma and a thermal load applicator to reduce stresses in the container walls by applying a thermal load, enhancing the plasma's brightness and extending the source's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If plasma-based radiation sources are used to increase brightness and spectral bandwidth, then illumination intensity and spectral bandwidth are improved, but thermal stress in container walls increases and lifetime decreases
Solution Approach 1:
The patent applies a thermal load to the container walls to modify their thermal parameters, specifically reducing thermal stress by pre-heating or thermally conditioning the walls before plasma operation. This parameter change allows the walls to better withstand the thermal environment, extending the radiation source lifetime while maintaining high brightness operation
Solution Approach 2:
The thermal load applicator applies a preliminary thermal action to the container walls before the plasma operates, creating a thermal precondition that counteracts the subsequent thermal stress from plasma generation. This preliminary anti-action prevents thermal shock and reduces wall stress, thereby extending component lifetime
2Adaptability or versatility
If plasma-based radiation sources are used to increase spectral bandwidth, then spectral bandwidth is improved, but thermal stress in container walls increases
Solution Approach 1:
By applying a thermal load to modify the thermal parameters of the container walls, the patent reduces thermal stress accumulation. This allows the system to operate with broader spectral bandwidth from plasma sources without the walls failing from thermal stress
Solution Approach 2:
The thermal load applicator acts as an intermediary between the plasma radiation source and the container walls, mediating the thermal interaction by pre-conditioning the walls to handle the thermal load from broad-spectrum plasma radiation
3Productivity
If measurement time is reduced for faster metrology, then productivity is improved, but light source brightness must be increased which increases thermal stress
Solution Approach 1:
The thermal load applicator modifies the thermal parameters of the container walls, enabling them to withstand higher brightness operation. This allows the use of brighter plasma sources that can perform measurements faster, improving productivity without the walls failing from thermal stress
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 solution provides higher brightness and extended lifespan of the radiation source, addressing thermal stress issues and improving spectral bandwidth while maintaining or reducing measurement time in lithographic metrology applications.
Implementation Method 1
a container comprising walls for defining a space for containing a gaseous medium in which plasma which emits plasma emitted radiation is generated following excitation of the gaseous medium by a driving radiation
Implementation Method 2
a thermal load applicator adapted to apply a thermal load to at least part of the walls of the container to reduce stresses in the walls
Data Source
AI summary
A radiation source apparatus comprising: a container comprising walls for defining a space for containing a gaseous medium in which plasma which emits plasma emitted radiation is generated following excitation of the gaseous medium by a driving radiation; and a thermal load applicator adapted to apply a thermal load to at least part of the walls of the container to reduce stresses in the walls.