Laser Internal Contour Cutting for Clean Planar Substrate Edges
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Solution Overview
Problem
Existing methods for cutting out contours from planar substrates, such as glass or crystal substrates, often result in undesired microcracks, melted edges, and non-uniform cut gaps due to high average laser power requirements and particle formation during ablation, leading to poor edge quality and potential disruptions in the substrate plane.
Innovation Solution
A method using a pulsed laser at a wavelength where the substrate is transparent, with optional continuous-wave laser modulation to create internal damage zones, combined with material removal and deformation steps to achieve precise separation with minimal crack formation, ensuring clean and straight edges by controlling laser parameters and using CO2 lasers with specific pulse durations and gas assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high average laser power is used for material vaporization or liquefaction, then cutting speed is improved, but edge quality deteriorates due to microcracks, melted edges, and non-uniform cut gaps
Solution Approach 1:
The patent employs pulsed laser irradiation instead of continuous high-power laser to periodically deliver energy to the substrate. This allows the material to cool between pulses, preventing excessive melting and microcrack formation while maintaining effective material removal through cumulative thermal damage zones, thereby resolving the contradiction between cutting speed and edge quality
Solution Approach 2:
The patent changes the laser parameter from high average power continuous wave to pulsed regime with controlled pulse duration, frequency, and peak power. This parameter transformation enables precise control over the thermal process, creating internal damage zones without the harmful side effects of high average power irradiation, thus improving both productivity and manufacturing precision
2Productivity
If laser ablation is used for material removal, then separation is achieved, but harmful factors increase due to particle formation during ablation
Solution Approach 1:
The patent modifies the laser processing parameters by using pulsed irradiation with optimized pulse duration and peak power settings. This creates thermal damage zones through controlled heating and cooling cycles rather than violent ablation, significantly reducing particle formation while maintaining effective separation efficiency
Solution Approach 2:
The patent converts the potentially harmful rapid ablation process into a beneficial controlled thermal damage process. By using pulsed laser with appropriate parameters, the thermal effects that would normally cause uncontrolled ablation and particle formation are transformed into controlled internal damage zones that achieve clean separation without harmful byproducts
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
The method enables high-speed, precise separation of contours with minimal crack formation and flaking, maintaining the integrity of the substrate without external disruptions, achieving clean and precise removal of internal contours and external edges with low roughness and high precision.
Implementation Method 1
the contour definition step is effected by irradiating the substrate with a laser (in particular: with a pulsed laser) at a wavelength at which the substrate material is essentially transparent
Implementation Method 2
the laser parameters are chosen such that, per laser pulse, a laser focal line is produced which produces, in the material of the substrate which is covered by the focal line, an induced absorption
Implementation Method 3
Since in addition material must be vaporised or liquefied, a high average laser power must be provided
Implementation Method 4
semiconductor wafers, glass elements and other substrates can be divided into various parts by the wavelength of the laser being greatly absorbed by the material. As a result, material removal which leads finally to division of the substrate into a plurality of parts is effected
Data Source
AI summary
A device for producing and removing an internal contour from a planar substrate comprising: a beam-producing- and beam-forming arrangement which is configured to perform: a contour definition step wherein a laser beam is guided over the substrate to produce a plurality of individual zones of internal damage in a substrate material along a contour line defining the internal contour; a crack deformation step, wherein the laser beam is guided over the substrate and produces a plurality of individual zones of internal damage in the substrate material to form a plurality of crack line portions that lead away from the contour line into the internal contour; and a material removal-step, wherein a laser beam directed towards the substrate surface that inscribes a removal line through a thickness of the substrate at the internal contour causes the internal contour to detach from the substrate.