Gallium Oxide Substrate Separation Using Laser Peel-Off Layers
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Solution Overview
Problem
The existing method of manufacturing semiconductor substrates from gallium oxide workpieces using a wire saw results in high material wastage, leading to poor productivity due to the need to discard 60-70% of the workpiece as cutting margin.
Innovation Solution
A substrate manufacturing method involving the formation of peel-off layers inside the workpiece using laser beams, with alternating indexing and laser beam application directions to create first and second peel-off layers, allowing separation of the workpiece into thinner substrates using these layers as initiation points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wire saw method is used to manufacture substrates from gallium oxide workpiece, then substrate can be manufactured with predetermined thickness, but 60-70% of workpiece is discarded as cutting margin leading to poor productivity
Solution Approach 1:
The patent replaces the mechanical wire saw cutting method with a laser-based peel-off layer formation method. Laser beams are used to create modified portions and cracks within the workpiece, forming peel-off layers that can be separated without mechanical contact. This substitution eliminates the need for large cutting margins while maintaining precise substrate thickness control, thereby improving productivity without sacrificing manufacturing precision.
Solution Approach 2:
The patent applies preliminary action by forming peel-off layers and cracks within the workpiece before final substrate separation. The laser processing creates modified portions and initiates cracks that serve as separation initiating points, allowing the workpiece to be cleanly divided into thin substrates with minimal material waste. This preliminary structuring enables efficient separation while maintaining high substrate quality.
2Manufacturing precision
If wire saw method is used, then substrate thickness can be controlled, but large cutting margin is required resulting in loss of substance
Solution Approach 1:
The patent replaces mechanical wire saw cutting with laser-based peel-off layer formation. The laser creates modified portions and cracks that define precise separation planes within the workpiece, eliminating the need for large mechanical cutting margins. This results in minimal material wastage while maintaining precise substrate thickness control.
Solution Approach 2:
The patent changes the physical state and properties of the workpiece material through laser heating and melting. By controlling laser parameters (power, speed, focus depth), the process creates specific modified portions and crack patterns that enable precise separation with minimal material loss, transforming the material locally to achieve the desired substrate thickness without excessive cutting margins.
3Loss of substance
If laser beam is focused inside workpiece for peel-off layer formation, then material wastage is reduced, but process complexity increases with alternating indexing and laser application
Solution Approach 1:
The patent segments the laser processing into distinct alternating steps: indexing feeding (positioning) and laser beam applying (processing). This segmentation allows precise control of the focused spot position within the workpiece while maintaining a relatively simple overall system architecture. The alternating sequence manages complexity by breaking down the continuous processing into discrete, controllable operations.
Solution Approach 2:
The patent implements dynamic control where the focused spot position is continuously adjusted relative to the workpiece through alternating indexing and laser application. The system dynamically switches between positioning mode (indexing) and processing mode (laser application), allowing flexible adaptation to different processing requirements while maintaining reduced material wastage through precise focal control.
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 significantly improves the productivity of substrate manufacturing by reducing material wastage and enhancing the efficiency of substrate production compared to traditional wire saw methods.
Implementation Method 1
first laser beam applying of moving the workpiece and a focused spot of a laser beam having a wavelength transmittable through the gallium oxide relative to each other along a first direction in a state in which the focused spot is positioned inside the workpiece
Implementation Method 2
second laser beam applying of moving the workpiece and the focused spot relative to each other along the first direction in a state in which the focused spot is positioned between the pair of adjacent first peel-off layers
Data Source
AI summary
A substrate manufacturing method includes peel-off layer forming of forming a plurality of rows of peel-off layers inside a workpiece, and, after the peel-off layer forming, separating the workpiece with the plurality of rows of peel-off layers being used as separation initiating points, to manufacture substrates. The peel-off layer forming includes first processing of forming a plurality of rows of first peel-off layers each including a modified portion and each being spaced from one another, and second processing of, after the first processing, forming a plurality of rows of second peel-off layers each including a modified portion and a crack extending from the modified portion and each being located between a pair of adjacent first peel-off layers of the plurality of rows of first peel-off layers.