Laser-Ablated Cooling Channels in Optical Substrates With Low Vibration
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Solution Overview
Problem
Existing methods for producing temperature-regulating hollow structures in substrates for EUV projection exposure apparatuses face challenges in achieving high precision, quality, and process speed while effectively counteracting flow-induced vibrations (FIVs).
Innovation Solution
The method involves a scanning trajectory with multiple scanning patterns that define specific pattern scanning paths, allowing for precise ablation of temperature-regulating hollow structures. This setup includes pattern jump paths and various scanning patterns such as line-to-line, meandering, sector, groove, contour, and single-hatch patterns, enabling flexible control over the ablation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ablation methods are used to produce temperature-regulating hollow structures, then the structures can be formed in the substrate, but manufacturing precision and quality are insufficient
Solution Approach 1:
The ablation process is segmented into multiple scanning patterns (line-to-line, meandering, sector, groove, contour, and single-hatch patterns) that can be selectively applied to different regions of the hollow structure. This segmentation allows optimization of ablation parameters for different zones, achieving high precision while maintaining productivity through parallel processing capabilities.
Solution Approach 2:
The method employs dynamic scanning trajectories with pattern jump paths that adaptively adjust the ablation focus movement. The control device can dynamically switch between different scanning patterns based on the current processing stage and requirements, enabling both high precision in critical areas and high productivity in less critical areas.
2Ease of manufacture
If the processing light beam is focused to achieve high energy density for ablation, then material removal is effective, but flow-induced vibrations occur
Solution Approach 1:
The method applies preliminary anti-action by using specific scanning patterns (particularly contour and groove patterns) that pre-establish stable ablation zones before transitioning to other patterns. These patterns are designed to minimize fluid flow disturbances from the outset, preventing FIVs before they can develop, while still achieving effective material removal through controlled energy delivery.
Solution Approach 2:
The method employs periodic scanning patterns such as meandering and sector patterns that create regular, predictable ablation sequences. This periodic action stabilizes the fluid-structure interaction by maintaining consistent ablation rhythms, thereby reducing flow-induced vibrations while preserving effective material removal capabilities.
3Manufacturing precision
If multiple scanning patterns are implemented for precise ablation control, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The control device is designed with multi-functionality to handle all six scanning patterns (line-to-line, meandering, sector, groove, contour, and single-hatch) through a unified control architecture. This universal design allows the same device to perform multiple functions with different patterns, achieving high manufacturing precision without proportionally increasing device complexity, as the underlying control mechanisms are shared across all patterns.
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 high flexibility and precision in programming the control device, enabling efficient incorporation of temperature-regulating hollow structures into substrates. It effectively counteracts FIVs and enhances the heat transfer and dissipation capabilities of the structures.
Implementation Method 1
at the ablation focus the processing light beam inputs energy with an energy density H into the substrate material, which is high enough that the substrate material is modified or ablated
Data Source
Figure 1
Figure 2~3
Figure 4A~5B
AI summary
In a method for incorporating temperature-regulating hollow structures (22) into a substrate (12), in particular into a substrate for an optical element, in particular for a mirror (10) for an EUV projection exposure apparatus, there are the following steps: (A) providing a substrate (12) consisting of a substrate material (12a); (8) progressively focusing a processing light beam (46) on ablation locations (56) at which temperature-regulating hollow structures (22) are intended to arise, such that the substrate material (12a) is modified or ablated at the ablation locations (54), wherein that side of the temperature-regulating hollow structure (22) which is reached first by the processing light beam (46) defines the top side of the temperature-regulating hollow structure (22) and the direction upward as positive z-direction of a coordinate system which is anchored in a rotationally fixed manner with the substrate (12); wherein (C) a scanning process is carried out in which the processing light beam (46) is guided with a focus (48) in such a way that an ablation focus (48A) is moved along a scanning trajectory (78) through the substrate (12), wherein at the ablation focus (48A) the processing light beam (46) inputs energy with an energy density H into the substrate material (12a), which is high enough that the substrate material (12a) is modified or ablated. (D) The scanning trajectory (78) comprises a plurality of scanning patterns (64, 116, 120) which each define a pattern scanning path and are scanned in scanning positions (74), such that an ablation volume defining a slice (62, 114, 166) is ablated in each scanning position (74(n)). (E) The scanning positions (74) are spaced apart from one another in a longitudinal direction (60) of the temperature-regulating hollow structure (22) to be produced. (F) The scanning trajectory (78) additionally comprises pattern jump paths (76) in each case between a scanning pattern (64) of a first scanning position (74(n)) and a scanning pattern (64) of a second scanning position (74(m)). Moreover, a method and a substrate (12) for producing an optical element (8), an optical element (8) and also a processing system (40) and an apparatus pertaining to semiconductor technology (6) are specified.