SiC Substrate Laser Cutting via Pulse Pitch Control
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Solution Overview
Problem
Cutting a planar object with a hexagonal SiC substrate having a main surface forming an off-angle with a c-plane using laser processing methods is challenging due to fractures easily extending in both the thickness and c-plane directions, making accurate cutting difficult.
Innovation Solution
A laser processing method that irradiates the object with pulse-oscillated laser light along a line, controlling the pulse pitch between 10 μm to 18 μm and pulse width between 20 ns to 100 ns, to form a modified region within the SiC substrate, facilitating fractures to extend primarily in the thickness direction while inhibiting extension in the c-plane direction, thus enabling accurate cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser light is irradiated to form a modified region for cutting SiC substrate, then cutting capability is improved, but fractures extend in both thickness and c-plane directions causing inaccurate cutting
Solution Approach 1:
The patent applies parameter changes by optimizing the pulse pitch to a specific range (10-18 μm) and pulse width (20-100 ns) to control fracture propagation. By adjusting these laser parameters, the modified region is formed with controlled characteristics that guide fractures to extend primarily in the thickness direction while suppressing extension in the c-plane direction, thereby resolving the contradiction between cutting capability and cutting accuracy
Solution Approach 2:
The patent employs periodic action through pulse-oscillated laser irradiation. The pulsed laser delivers energy in periodic bursts with controlled pitch and width, creating a modified region that systematically guides fracture propagation. This periodic energy delivery allows precise control over where and how fractures extend, enabling accurate cutting along the desired line while preventing unwanted fracture spread in the c-plane direction
2Productivity
If fractures are made to extend easily in thickness direction from modified region, then cutting efficiency is improved, but fractures also extend in c-plane direction reducing precision
Solution Approach 1:
The patent resolves this contradiction by changing the laser parameters to a specific combination: pulse pitch of 10-18 μm and pulse width of 20-100 ns. This parameter optimization creates a modified region with specific stress distribution that promotes fracture extension in the thickness direction (improving efficiency) while suppressing fracture propagation in the c-plane direction (maintaining precision). The controlled parameters ensure fractures follow the desired cutting path without deviating into the c-plane
Solution Approach 2:
The patent applies local quality by creating a modified region with specific local characteristics through controlled laser irradiation. The modified region has differentiated properties that locally guide fracture propagation: it facilitates fracture extension in the thickness direction where cutting is desired, while simultaneously creating barriers or stress distributions that inhibit fracture extension in the c-plane direction. This localized control of fracture behavior resolves the contradiction between efficiency and precision
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 allows for precise cutting of the hexagonal SiC substrate along a line, ensuring that fractures extend in the thickness direction and not in the c-plane direction, thereby achieving accurate and efficient cutting of the planar object.
Implementation Method 1
irradiating the object with pulse-oscillated laser light along the line such that a pulse pitch becomes 10 μm to 18 μm while locating a converging point of the laser light within the SiC substrate, thereby forming a modified region to become a cutting start point within the SiC substrate along the line
Data Source
AI summary
A planar object to be processed 1 comprising a hexagonal SiC substrate 12 having a front face 12a forming an angle corresponding to an off-angle with a c-plane is prepared. Subsequently, the object 1 is irradiated with pulse-oscillated laser light L along lines to cut 5a, 5m such that a pulse pitch becomes 10 μm to 18 μm while locating a converging point P of the laser light L within the SiC substrate 12. Thereby, modified regions 7a, 7m to become cutting start points are formed within the SiC substrate 12 along the lines 5a, 5m.