Diamond Substrate Cleavage Using Laser-Formed (111) Modified Layers
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Solution Overview
Problem
The existing methods for manufacturing diamond substrates, particularly those with a (111) orientation, face challenges such as high processing loss and difficulty in achieving high-precision substrates for magnetic sensors due to the hardness of diamond and limitations in delamination 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 crack on the surface of a single crystal diamond block, allowing for spontaneous cleavage and delamination with minimal processing loss, thereby reducing the thickness of the cutting margin and improving yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ion implantation is used to introduce a defective layer for delamination, then delamination can be achieved, but a device in a high vacuum environment is required and the processing time is long
Solution Approach 1:
The patent replaces the ion implantation method (which requires complex vacuum devices) with a laser-based method. The laser beam is focused on the diamond substrate surface to create a modified layer that enables delamination, substituting the mechanical/physical ion implantation process with an optical field-based approach that does not require vacuum environment.
Solution Approach 2:
The patent changes the processing parameters by using laser irradiation with specific conditions (wavelength, power, scanning speed) to create a modified layer at a predetermined depth. This allows control over the delamination depth and reduces processing time compared to ion implantation, while avoiding the need for vacuum environment.
2Ease of manufacture
If ion implantation is used to introduce a defective layer for delamination, then delamination can be achieved, but the processing time is long
Solution Approach 1:
The patent replaces the time-consuming ion implantation process with laser irradiation. The laser can rapidly scan across the substrate surface and create the modified layer in a much shorter time, eliminating the lengthy processing time associated with ion implantation while maintaining delamination capability.
Solution Approach 2:
The patent uses periodic laser scanning with controlled pulse duration and repetition rate to efficiently create the modified layer. The laser beam scans back and forth across the substrate in a periodic manner, rapidly depositing energy to form the modified layer at the desired depth without requiring prolonged processing time.
3Ease of manufacture
If conventional slicing and polishing methods are used to process diamond substrates, then substrates can be manufactured, but processing loss due to cutting margin occurs
Solution Approach 1:
The patent performs preliminary action by creating a modified layer at a predetermined depth from the surface before any cutting or polishing occurs. This modified layer acts as a pre-defined delamination plane, allowing the substrate to be cleanly separated at the exact desired thickness without requiring additional cutting margins, thereby reducing material loss.
Solution Approach 2:
The patent segments the diamond substrate into distinct portions by creating a modified layer that serves as a delamination interface. This allows clean separation of the substrate from the bulk crystal at the predetermined depth, eliminating the need for conservative cutting margins and reducing material waste.
4Manufacturing precision
If polishing is used to reduce substrate thickness, then desired thickness can be achieved, but it is especially difficult to polish a bulk crystal of single crystal diamond with the [111] orientation
Solution Approach 1:
The patent performs preliminary action by creating a modified layer at the exact predetermined depth from the surface using laser irradiation. This pre-established delamination plane eliminates the need for subsequent polishing to achieve the desired thickness, avoiding the difficulty of polishing [111] oriented diamond while maintaining high manufacturing precision.
Solution Approach 2:
The patent replaces the mechanical polishing process (which is especially difficult for [111] oriented diamond) with a laser-based method to create the modified layer. The laser irradiation process does not suffer from the orientation-dependent polishing difficulties and can precisely create the delamination plane at the desired depth regardless of 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 method enables the efficient production of (111) substrates with reduced processing loss and improved yield, facilitating the use of diamond substrates in high-precision magnetic sensors and other applications by simplifying the processing and increasing productivity.
Implementation Method 1
radiating the 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
Implementation Method 3
forming a cleavage plane at the predetermined depth of the remaining region of the upper surface of the block by spontaneously propagating cleavage from the modified layer
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, a step of forming a modified layer 20, which includes a processing mark 21 of graphite and a crack 22b extending along a surface (111) around the processing mark 21, in a partial region of the upper surface 10a of the block 10 along the surface (111) of the single crystal diamond, along the surface (111) of the single crystal diamond at a predetermined depth from the upper surface 10a of the block 10 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, and a step of forming a cleavage plane 25 at the predetermined depth of the remaining region of the upper surface 10a of the block 10 by spontaneously propagating cleavage from the modified layer 20.