Silicon Carbide Laser Peeling with Guided Crack Length Control
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Solution Overview
Problem
The challenge in processing silicon carbide substrates lies in controlling the length of cracks generated during laser processing, particularly in off-axis crystals where the top surface is not parallel to the C-plane, leading to unpredictable crack propagation and difficulty in controlling the longitudinal component of the crack.
Innovation Solution
A method involving two lasers is employed, where a first laser forms modified traces inside the workpiece, and a second laser with higher absorptance in these traces generates cracks, guided by the modified traces to control crack propagation, using different paths and angles relative to the crystal orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pulsed laser is used for silicon carbide crystal peeling and wafer thinning, then processing can be performed on the workpiece, but the crack length in the longitudinal direction cannot be controlled due to crack fluctuation along the C-plane
Solution Approach 1:
The patent applies preliminary action by first forming modified traces using a first laser before generating cracks with a second laser. These pre-formed modified traces serve as controlled initiation points that guide crack propagation, preventing random fluctuation along the C-plane and enabling precise control of crack length in the longitudinal direction.
Solution Approach 2:
The patent introduces modified traces as an intermediary structure between the laser processing and crack generation. These modified traces act as mediators that channel and control the crack propagation path, transforming the uncontrolled crack fluctuation problem into a controlled process where crack length can be precisely managed.
2Ease of manufacture
If off-axis silicon carbide crystal is used, then the substrate can be manufactured, but the top surface is not parallel to the C-plane causing unpredictable crack propagation
Solution Approach 1:
The patent applies local quality by creating modified traces at specific locations within the workpiece using the first laser. These localized modifications create regions with different properties that serve as controlled crack initiation points, compensating for the global issue of off-axis crystal orientation and surface non-parallelism.
Solution Approach 2:
The patent changes the physical state and optical parameters of the silicon carbide material by forming modified traces through first laser irradiation. This parameter change creates regions with altered absorptance and structural properties that enable controlled crack initiation and propagation, overcoming the challenges posed by off-axis crystal orientation.
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 precise control of crack length and reduces fluctuations, improving processing quality by ensuring cracks initiate at specific modified traces, thus minimizing unwanted crack amplification and material loss during peeling or thinning.
Implementation Method 1
focusing first laser inside a workpiece to form one or more modified traces inside the workpiece
Implementation Method 2
absorptance to the second laser in the modified traces being greater than absorptance to the second laser in a region outside the modified traces
Implementation Method 3
irradiating the modified traces with second laser to form absorption traces, so as to enable crack generation inside the workpiece
Data Source
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AI summary
The present disclosure is applied to the field of laser processing technologies, and provides a laser processing method, an apparatus, a device, a processing device, and a storage medium. The laser processing method includes: focusing first laser inside a workpiece to form one or more modified traces inside the workpiece; and irradiating the modified traces with second laser to form absorption traces, so as to enable crack generation inside the workpiece. Absorptance to the second laser in the modified traces is greater than absorptance to the second laser in a region outside the modified traces. According to the laser processing method provided in embodiments of the present disclosure, the length of the longitudinal component of the crack can be controlled.