Laser Substrate Cutting Aligned to Crystal Orientation
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Solution Overview
Problem
The existing laser processing techniques for cutting crystalline substrates often result in level differences on the cut surface due to deviations of the cutting line from the crystal orientation, leading to reduced yield and quality of chips.
Innovation Solution
A laser processing device and method that sets a reference line indicating the crystal orientation of the substrate by imaging cracks formed along candidate lines, allowing the cutting line to be aligned parallel to this reference, thereby preventing deviations and ensuring accurate cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the cutting line is set without considering crystal orientation, then the cutting process is simple, but level differences appear on the cut surface and chip yield is reduced
Solution Approach 1:
The patent applies preliminary action by setting multiple candidate lines at different angles before the actual cutting process. The system pre-calculates and prepares several potential cutting paths, then selects the optimal one that aligns with crystal orientation. This preliminary setup allows the cutting process to proceed smoothly without complex real-time adjustments while ensuring accurate alignment with crystal structure, thereby preventing level differences on the cut surface.
Solution Approach 2:
The patent changes the parameter of cutting line angle by testing multiple candidate lines at different angles (e.g., 0°, 45°, 90° relative to reference). By varying this angular parameter and evaluating the resulting crack propagation, the system identifies the optimal angle that matches crystal orientation. This parameter adjustment enables precise alignment without complicating the overall manufacturing process.
2Manufacturing precision
If multiple candidate lines are tested to find the optimal cutting line, then cutting precision is improved, but processing time increases
Solution Approach 1:
The patent applies partial action by testing only a limited set of predetermined candidate lines at specific angles rather than exhaustively testing all possible angles. Typically, 3-5 candidate lines at standard angular intervals (0°, 45°, 90°) are sufficient to identify the optimal cutting path. This partial testing approach achieves the necessary precision while minimizing the time investment, avoiding excessive processing overhead.
Solution Approach 2:
The system uses feedback from imaging the crack propagation along each candidate line to determine which line best aligns with crystal orientation. The crack pattern serves as feedback indicating the degree of alignment - cracks that follow a straight path parallel to the candidate line indicate good alignment. This feedback mechanism allows rapid evaluation of multiple candidates and quick selection of the optimal line, reducing overall processing time.
3Ease of operation
If the cutting line deviates from crystal orientation, then setup is easier, but chip quality and yield are reduced
Solution Approach 1:
The patent applies self-service by using the material's own crystal structure to guide the cutting line selection. The crack propagation naturally reveals the crystal orientation through its pattern, and this information is used to automatically select the optimal cutting line. The system leverages the inherent properties of the workpiece itself rather than requiring external references or complex alignment procedures, making setup easier while ensuring high chip yield through proper alignment.
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 inhibits the cutting line from deviating with respect to the crystal orientation, reducing level differences on the cut surface and improving the yield and quality of chips by ensuring precise alignment.
Implementation Method 1
a laser light source configured to emit laser light; a converging optical system configured to converge the light emitted from the laser light source at the object to be processed supported by the support table
Implementation Method 2
a modified region is formed inside the substrate along each of the plurality of candidate lines, and a crack reaches the front surface of the object to be processed from the modified region
Data Source
AI summary
A laser processing device includes: a support table; a laser light source; a converging optical system; an imaging unit configured to image a front surface of an object; a candidate line setting unit configured to set a plurality of candidate lines; an operation controller configured to control operation of at least one of the support table, the laser light source, and the converging optical system such that a modified region is formed inside the object along each of the plurality of candidate lines, and a crack reaches the front surface of the object from the modified region; and a reference line setting unit configured to set a reference line determined as a line indicating a crystal orientation of the object on the basis of an image of the crack.