Selective Laser Etching with Guided Etchant Fronts for Long Channels
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Solution Overview
Problem
Selective laser etching processes face limitations in creating structures with high aspect ratios due to long etching times and over-etching issues, particularly when forming long channels, which result in conical shapes and undesirable material removal outside the intended structure.
Innovation Solution
A method and system where an etchant front is guided along the workpiece processing area to selectively remove the laser-modified material, using an etching device to generate a locally concentrated etchant and potentially enhanced by ultrasonic waves, allowing for precise and efficient removal of modified material without over-etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the workpiece is placed in an etching bath for selective laser etching, then the laser-modified material can be removed, but the etching time becomes excessively long and over-etching occurs
Solution Approach 1:
The patent segments the etching process by introducing auxiliary access points that divide the etching pathway into multiple routes. The etching agent can reach the laser-modified material through these access points, allowing the etching front to advance more efficiently through the workpiece without requiring prolonged immersion in an etching bath.
Solution Approach 2:
The patent introduces auxiliary access points as intermediary structures that facilitate the transport of the etching agent to the laser-modified material. These access points act as conduits that enable the etching agent to reach deep within the workpiece more quickly, reducing the overall etching time while maintaining precision.
2Length of moving object
If long channels are etched using selective laser etching, then high aspect ratio structures can be formed, but over-etching occurs at the channel entrance creating conical shapes
Solution Approach 1:
The patent segments the etching process into multiple pathways by creating auxiliary access points. This segmentation allows the etching agent to approach the laser-modified material from different directions, enabling better control over the etching front and preventing excessive etching at the channel entrance that would create conical shapes.
Solution Approach 2:
The patent applies local quality by creating specific auxiliary access points at strategically located positions rather than uniformly across the entire workpiece. This allows the etching agent to be directed precisely where needed, maintaining the desired cylindrical shape of channels while enabling the formation of long channels with high aspect ratios.
3Productivity
If auxiliary access points are created to enable etching of deep structures, then etching efficiency improves, but the design flexibility of the structure is limited
Solution Approach 1:
The patent enhances design flexibility by allowing the auxiliary access points to serve multiple functions: they facilitate efficient etching of deep structures while also being integrable into various structural designs. The access points can be positioned and configured to match different geometric requirements, enabling the method to adapt to diverse structural designs rather than limiting them.
Solution Approach 2:
The patent introduces dynamic adaptability by allowing the configuration and positioning of auxiliary access points to be adjusted according to the specific design requirements. This dynamic approach enables the etching process to be optimized for different structural geometries, maintaining both high etching efficiency and design versatility.
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
Enables the formation of macroscopic structures with high aspect ratios, such as channels up to 500 mm long, with minimal over-etching, and allows for flexible design without the need for auxiliary access channels, improving the precision and efficiency of the selective laser etching process.
Implementation Method 1
The laser irradiation results in a structural modification of the workpiece material in the focus area. This structural modification occurs through absorption of the laser radiation in the workpiece, primarily by so-called multiphoton absorption.
Implementation Method 2
In a second step, following the structural modification of the workpiece material with laser radiation, an etching process is carried out, in which the laser-treated workpiece is exposed to an etching agent.
Implementation Method 3
An ultrasonic device may also be used to ensure improved exchange of the etching agent.
Data Source
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AI summary
The present invention relates to a method for forming a structure (1) in a workpiece (2) by selective laser etching, wherein a) workpiece material (3) of the workpiece (2) in a workpiece processing area (4) of the workpiece (2) corresponding to the structure (1) to be formed is structurally modified by laser radiation (5); and wherein b) the modified workpiece material (8) is removed from the workpiece (2) using an etching agent. In order to enable structure formation in the workpiece (2) in such a method without over-etching or with only a small degree of over-etching, it is proposed that an etching agent front (10) generated by an etching device (9) is guided along the workpiece processing area (4) to remove the modified workpiece material (8).