Diamond Wafer Separation via Graphitized Interface Laser Splitting
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Solution Overview
Problem
Conventional slicing techniques for single crystal diamond wafers, such as sawing and etching, result in significant cutting loss and are time-consuming, making them economically unviable.
Innovation Solution
Creating a damaged layer beneath the upper surface of a seed wafer, annealing it to form a graphitized interface, and then laser-splitting the seed wafer along this interface to separate the diamond film or wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional slicing techniques (sawing, laser sawing, etching) are used to separate diamond wafers, then the wafer can be separated from the seed substrate, but significant cutting loss occurs and the process is time-consuming
Solution Approach 1:
A damaged layer is created beneath the upper surface of the seed wafer before separation. This preliminary damage to the crystal lattice at a specific depth creates a predetermined weak plane that facilitates subsequent easy separation, reducing both material loss and processing time compared to conventional slicing methods
Solution Approach 2:
The damaged layer undergoes a phase transition or structural change that creates a graphitized interface or weakened bonding region. This phase change at the damaged layer depth enables clean separation with minimal material loss when laser energy is applied, as the transformed layer has different properties than the intact diamond crystal
2Productivity
If conventional etching techniques are used to separate diamond wafers, then separation can be achieved, but the etch periods are too long (on the order of days) to be economically viable
Solution Approach 1:
The damaged layer is created in advance at the desired separation depth, preparing the material structure for rapid separation. This preliminary action eliminates the need for lengthy etching processes by pre-creating the separation plane, reducing separation time from days to minutes through subsequent laser processing
Solution Approach 2:
The slow chemical etching process is replaced with a laser-based separation method acting on the pre-damaged layer. The laser rapidly heats and separates the damaged layer material, substituting a fast thermal-mechanical process for the slow chemical etching process, thereby dramatically reducing separation time
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 reduces cutting loss, is more time-efficient, and provides a more economically viable process for producing diamond wafers compared to conventional techniques.
Implementation Method 1
applying light from a laser to the damaged layer to separate the formed crystalline structure from the seed wafer
Implementation Method 2
annealing the damaged layer to form a graphitized interface beneath the upper surface of the seed wafer
Data Source
AI summary
Methods of forming a crystalline wafers or films such as a diamond wafer or film are disclosed. Such a method may include creating a damaged layer in a seed wafer at a depth from a seed wafer upper surface. The seed wafer may include a diamond crystalline structure. The method may also include growing a diamond epitaxial layer on the seed wafer upper surface via a chemical vapor deposition (CVD) process. A growth temperature of the CVD process may convert the damaged layer into a graphitized interface between the seed wafer and the diamond epitaxial layer. The method may further include applying light from a laser to the graphitized interface to separate the diamond epitaxial layer from the seed wafer and obtain the diamond wafer.