Laser-Modified Glass Etching for High-Aspect-Ratio Apertures
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Solution Overview
Problem
Existing methods for creating recesses or apertures in transparent materials, such as glass, face limitations in achieving precise control over the aspect ratio and geometry due to isotropic etching and inability to produce structures with large aspect ratios.
Innovation Solution
The method involves selectively modifying the material along a beam axis using electromagnetic radiation, creating modifications with different characteristics to achieve heterogeneous etching rates, allowing for targeted adjustment of recesses and apertures through varying pulse energy, beam shape, and etching conditions, including the use of etching resist and multiple etching steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If isotropic etching is used to create recesses in transparent materials, then the etching process is simple and uniform, but the aspect ratio and geometry control is poor and structures with large aspect ratios cannot be achieved
Solution Approach 1:
The patent applies local quality by creating spatially varying modification characteristics along the beam axis through controlled laser parameters. Different regions of the material receive modifications with different densities or types, causing the etching rate to vary locally. This enables precise control over the recess geometry and aspect ratio while maintaining a relatively simple etching process using standard etching chemicals.
2Manufacturing precision
If laser radiation exposure time is extremely short to achieve cylindrical modification zone, then the aperture diameter is constant, but the ability to create complex geometries is limited
Solution Approach 1:
The patent employs dynamics by making the laser radiation parameters variable during the exposure process. The pulse energy, duration, or wavelength can be dynamically adjusted to create different modification characteristics at different positions along the beam axis. This dynamic control enables the creation of complex recess geometries while maintaining precise aperture diameter control through the cylindrical modification zone.
3Ease of manufacture
If uniform modification characteristics are produced along the beam axis, then the etching process is simple, but the etching rate is uniform and geometry control is limited
Solution Approach 1:
The patent applies parameter changes by systematically varying laser radiation parameters such as pulse energy, pulse duration, wavelength, or repetition rate along the beam axis. These parameter changes create spatially differentiated modification characteristics in the material. When subsequent etching is performed, different regions etch at different rates, enabling precise control over recess geometry while keeping the etching process itself relatively simple and using standard etchants.
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 enables precise control over the geometry of recesses, including adjustable cone angles and diameters, reducing microcracks and allowing for complex geometries, suitable for applications like microfluidics and nozzle plates.
Implementation Method 1
selectively modifying the material along a beam axis by electromagnetic radiation, in particular of a laser
Implementation Method 2
The electromagnetic radiation produces modifications having different characteristics in the material along the beam axis such that the etching process in the material is heterogeneous
Data Source
AI summary
A method for creating at least one recess, in particular an aperture, in a transparent or transmissive material, includes: selectively modifying the material along a beam axis by electromagnetic radiation; and creating the at least one recess by one or more etching steps, using different etching rates in a modified region and in non-modified regions. The electromagnetic radiation produces modifications having different characteristics in the material along the beam axis such that the etching process in the material is heterogeneous and the etching rates differ from one another in regions modified with different characteristics under unchanged etching conditions.