Laser-Machined Cooling Channels Around Inclusions in EUV Mirror Substrates
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Solution Overview
Problem
Existing methods for producing temperature-controlling hollow structures in substrates, such as mirror substrates for EUV projection exposure apparatuses, often result in irregularly formed channels with non-uniform cross sections due to gas bubbles and other inclusions in the substrate.
Innovation Solution
A method that involves measuring the locations of inclusions in the substrate and adjusting the direction of the processing light beam to avoid intersecting with these inclusions, ensuring that the beam axis does not intersect with gas bubbles or other inclusions, thereby maintaining a consistent and uniform cross section of the temperature-controlling hollow structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a processing light beam is focused onto processing locations to produce cooling channels, then the substrate material is modified or removed to create hollow structures, but the walls of the cooling channels are formed irregularly due to gas bubbles and inclusions in the substrate
Solution Approach 1:
The patent applies preliminary action by measuring the locations of gas bubbles and inclusions in the substrate before the material modification process. This advance detection allows the processing path to be planned to avoid these harmful factors, ensuring uniform cooling channel walls without being disrupted by bubbles or inclusions during the actual processing.
Solution Approach 2:
The patent implements feedback by using measurement data about bubble locations to adjust the processing path in real-time. The system continuously monitors the substrate characteristics and modifies the beam trajectory accordingly, ensuring that the processing light beam avoids intersecting with gas bubbles and inclusions, thereby maintaining manufacturing precision.
2Manufacturing precision
If the processing light beam intersects with gas bubbles in the substrate, then the beam path is disrupted causing irregular channel walls, but avoiding all inclusions would require complex real-time adjustments
Solution Approach 1:
The patent reduces device complexity by performing preliminary measurement of bubble locations before processing. This advance knowledge allows the system to pre-calculate an optimal processing path that avoids inclusions, eliminating the need for complex real-time adjustments during material modification while still achieving smooth channel walls.
Solution Approach 2:
The patent solves the complexity problem by adding a spatial dimension to the processing approach. Instead of trying to control the beam in real-time when bubbles are encountered, the system uses three-dimensional location data of bubbles to plan a completely different processing trajectory in space, avoiding intersections before they occur.
3Productivity
If cooling channels are produced with irregular cross sections, then the substrate can be processed faster, but the structural integrity and temperature control effectiveness are reduced
Solution Approach 1:
The patent maintains both productivity and reliability by performing preliminary measurement and path planning. This allows the system to process at high speed along an optimized path that avoids bubbles, rather than slowing down to detect and avoid them in real-time. The uniform channel geometry is ensured from the start, maintaining temperature control effectiveness while preserving fast processing.
Solution Approach 2:
The patent replaces complex real-time mechanical adjustment systems with a pre-calculated digital path planning approach. By substituting the need for complex real-time control mechanisms with advance computational planning based on measured bubble locations, the system achieves both high processing speed and reliable uniform channel formation.
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 allows for the production of temperature-controlling hollow structures with more uniform cross sections and smoother inner surfaces, reducing the risk of process interruptions and enhancing the structural integrity of the substrates.
Implementation Method 1
working the temperature-controlling hollow structure into the substrate by focusing a processing light beam with a beam axis aligned along a standard direction successively onto processing locations at which the temperature-controlling hollow structure is to be produced, as a result of which the substrate is modified or removed at the processing locations
Data Source
Figure 1
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Figure 5a~5d
AI summary
In the case of a method for producing a temperature-controlling hollow structure in a substrate, in particular in a mirror substrate of an EUV projection exposure apparatus or another semiconductor technology apparatus, first of all a substrate (12) consisting of a substrate material is provided. The substrate (12) is surveyed in order to ascertain where gas bubbles or other inclusions (52) are in the substrate (12). Then, a temperature-controlling hollow structure, which may be e.g. a cooling channel (22), is worked into the substrate (12) by focusing a processing light beam (34) with a beam axis (48) aligned along a standard direction successively onto processing locations (44) at which the temperature-controlling hollow structure (22) is to be produced. As a result, the substrate material is modified or removed at the processing locations (44). If an inclusion (52) is on the beam axis (48) aligned along the standard direction, the direction of the beam axis (48) relative to the mirror substrate (12) is changed such that the beam axis (48) does not intersect the inclusion (50). Any residues (74) can be removed by inserting a lance (76) into the cooling channel in order to break off the residues.