Laser-Shaped Substrate Recessing With One-Sided Anisotropic Etching
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Solution Overview
Problem
Laser-induced deep etching processes for creating recesses in substrates are inefficient due to the need for additional protection measures and material property changes on opposite surfaces, requiring high time and control effort, and result in conical depressions rather than planar boundaries.
Innovation Solution
Spatial beam shaping of a laser beam along a beam axis to create defects without material removal, followed by anisotropic etching to introduce modifications that extend from one surface to a position between surfaces, allowing for one-sided recess creation without altering the opposite surface properties and achieving homogeneous etch removal with reduced process time and effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser-induced deep etching is used to create recesses in substrates, then manufacturing precision is improved, but device complexity increases due to additional protection measures required on opposite surfaces
Solution Approach 1:
The laser beam is focused to create modifications only in the specific region where the recess is desired, rather than treating the entire substrate. This localized modification approach allows precise recess creation without requiring protection of the entire opposite surface, as the laser parameters (focus position, power, scan speed) are controlled to confine the modification zone.
Solution Approach 2:
The substrate is pre-treated by creating laser-induced modifications (such as color centers or stress patterns) before the actual etching process. This preliminary laser treatment prepares the substrate by creating regions with enhanced etch susceptibility, allowing the subsequent etching step to proceed more efficiently and with better precision without requiring additional protective measures.
2Manufacturing precision
If laser-induced deep etching is used to create recesses, then manufacturing precision is improved, but loss of time increases due to high control effort required
Solution Approach 1:
The laser beam continuously scans through the substrate material along a predetermined path, creating a continuous line of modifications without interruption. This continuous scanning approach, as opposed to discrete point-by-point processing, significantly reduces the number of positioning and repositioning operations, thereby reducing control effort and processing time while maintaining precision.
Solution Approach 2:
The laser-induced modifications automatically create regions that are preferentially etched by the etching medium, eliminating the need for complex real-time control during the etching process. The laser treatment self-organizes the substrate properties such that the etching proceeds in the desired pattern without requiring continuous monitoring or adjustment, reducing control effort.
3Manufacturing precision
If modifications pass between opposite sides of the substrate, then recess creation is achieved, but harmful factors increase due to changes in material properties on the opposite surface
Solution Approach 1:
The laser beam parameters are controlled to create modifications that are confined to a specific depth range within the substrate. By adjusting the focus position and using appropriate laser power and scan speed, the modifications are localized to the region where the recess is needed, preventing unwanted changes in material properties on the opposite surface while still achieving precise recess 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 method enables efficient production of recesses with low roughness and homogeneous material thickness, reducing process time and control effort while maintaining substrate properties on the opposite surface, and allows for the creation of complex structures with minimal additional steps.
Implementation Method 1
defects are produced in the substrate by means of the laser beam along the beam axis, without material removal from the substrate as a result of the laser radiation, one or more defects forming at least one modification in the substrate
Implementation Method 2
the recess or the material weakening is produced by the action of an etching medium and by successive etching by an anisotropic material removal in the respective region of the modifications in the substrate
Data Source
AI summary
A method for introducing a recess into a substrate, and/or for reducing a material, includes spatially beam shaping a focus of a laser beam along a beam axis, whereby defects are produced in the substrate along the beam axis without there being any material removal. One or more of the defects forms a modification in the substrate, so that subsequently the recess and/or the material thickness reduction is produced by action of an etching medium by an anisotropic material removal. An additional modification is introduced into the substrate along an additional beam axis that is parallel to and spaced from the beam axis, the additional modification having an extent between a first outer surface of the substrate and a position within the substrate that is at a distance from a second, opposite outer surface of the substrate.