Diamond Substrate Delamination by Internal Laser Graphitization
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Solution Overview
Problem
The existing methods for processing single crystal diamond substrates, particularly those with a [111] orientation, face challenges such as high processing loss and difficulty in achieving high-density nitrogen-vacancy centers, which are essential for magnetic sensors, due to the hardness of diamond and the inefficiencies of current techniques like ion implantation and polishing.
Innovation Solution
A method involving the use of pulsed laser light to form a modified layer with a graphite processing mark and cracks along the [111] surface of the diamond, allowing for spontaneous delamination with minimal processing loss, thereby reducing the cutting margin and improving yield in manufacturing diamond substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ion implantation is used to introduce defective layers for smart cut technique, then delamination can be achieved, but high vacuum environment equipment is required and processing time is long
Solution Approach 1:
The patent replaces the ion implantation process (which requires complex vacuum equipment) with a laser-based processing method. The laser irradiation creates a modified layer that enables delamination without requiring high vacuum environment equipment, thus substituting a complex mechanical/physical system with a simpler optical system.
Solution Approach 2:
The patent changes the processing parameters by using laser irradiation instead of ion implantation. The laser parameters (wavelength, power, pulse duration) are optimized to create the modified layer at the desired depth, enabling delamination with simpler equipment and reduced processing time.
2Productivity
If conventional slicing methods are used to process diamond substrates, then substrates can be manufactured, but significant processing loss occurs as cutting margin
Solution Approach 1:
The patent applies laser irradiation in advance to create a modified layer at the desired substrate thickness position before actual separation. This preliminary action defines the cutting line precisely, allowing the substrate to be separated with minimal cutting margin and reducing material loss.
Solution Approach 2:
The patent segments the diamond crystal into a substrate portion and a remaining portion by creating a modified layer at the interface. The modified layer acts as a predetermined separation plane, enabling clean division with minimal material loss compared to conventional slicing that requires wider cutting margins.
3Manufacturing precision
If polishing is used to process (111) oriented diamond crystals, then substrates can be manufactured, but the process is especially difficult and time-consuming
Solution Approach 1:
The patent replaces the mechanical polishing process with laser irradiation to create the modified layer. This substitution eliminates the time-consuming mechanical removal of material and replaces it with a faster optical processing method that achieves the same functional result of defining the substrate thickness.
Solution Approach 2:
The patent utilizes phase transition of diamond under laser irradiation to create the modified layer. The laser energy causes localized phase changes in the diamond crystal structure, creating the modified layer that enables delamination without requiring prolonged mechanical polishing.
4Area of stationary object
If bulk crystal diamond is grown by CVD method to increase area, then larger substrates can be produced, but the crystal orientation must match the base crystal orientation
Solution Approach 1:
The patent applies laser irradiation locally to specific regions of the diamond crystal to create the modified layer. This localized processing allows the substrate to be separated with the desired orientation and dimensions from the larger CVD-grown crystal, enabling flexibility in substrate orientation selection while maintaining the benefit of large-area CVD growth.
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 enables the production of [111] substrates with reduced processing loss and improved yield, facilitating the application of single crystal diamond in high-precision magnetic sensors and other devices.
Implementation Method 1
radiating laser light on the upper surface of the block from the laser condensing unit and condensing the laser light inside the block
Implementation Method 2
forming a modified layer, which includes a processing mark of graphite
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A method of manufacturing a diamond substrate includes: a step of placing a laser condensing unit 190 configured to condense laser light B so as to face an upper surface 10a of a block 10 of single crystal diamond; and a step of forming a modified layer 20, which includes a processing mark 21b of graphite and a crack 22b extending along a surface (111) around the processing mark 21b, along the surface (111) of the single crystal diamond at a predetermined depth from an upper surface of the block by radiating the laser light B on the upper surface 10a of the block 10 from the laser condensing unit 190 under predetermined conditions and condensing the laser light B inside the block 10, and moving the laser condensing unit 190 and the block 10 in a relative manner two-dimensionally.