Sapphire Substrate Laser Processing Phase Transformation
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Solution Overview
Problem
Conventional laser processing methods for sapphire substrates result in poor cutting surfaces, decreased luminance, fine dust generation, and limitations in integrating multiple functional devices due to amorphous regions, heat generation, and defects like cracks or peeling between the substrate and nitride layers.
Innovation Solution
A laser processing method and apparatus that uses a short pulse laser beam, a beam shaping module, and a light concentrating unit to form a phase transformation area within the sapphire substrate while avoiding the stacked portions, preventing heat effects and maintaining high luminance and device density integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional laser processing apparatus is used to scribe or cut a sapphire substrate, then the cutting process can be performed, but the cutting surface quality deteriorates and luminance decreases due to amorphous region formation
Solution Approach 1:
The patent applies parameter changes by using a short pulse laser beam with specifically controlled pulse width (10-1000 ps) and wavelength (343-385 nm) to transform the laser processing parameters. This enables precise control of the laser beam energy deposition, creating a phase transformation area without forming amorphous regions, thereby improving cutting surface quality while preventing luminance decrease.
Solution Approach 2:
The patent employs periodic action through short pulse laser irradiation, where the laser beam is applied in discrete pulses rather than continuous irradiation. This periodic energy input allows the material to cool between pulses, preventing excessive heat accumulation and amorphous region formation, thus maintaining both cutting surface quality and substrate luminance.
2Productivity
If a conventional laser processing apparatus is used to cut the sapphire substrate, then the cutting process can be completed, but fine dust is generated which adversely affects element characteristics
Solution Approach 1:
The patent changes the laser processing parameters by using a short pulse duration (10-1000 ps) and specific wavelength (343-385 nm), which enables ablation of the sapphire substrate with minimal material ejection. This parameter optimization reduces fine dust generation while maintaining cutting productivity, as the short pulse duration limits the time for dust particle formation and ejection.
3Productivity
If the sapphire substrate is processed with a conventional laser processing apparatus, then cutting can be performed, but the cut region area is relatively large which limits high density integration of multiple functional devices
Solution Approach 1:
The patent utilizes parameter changes by employing a short pulse laser beam with high peak power density and specific wavelength, which concentrates the energy into a smaller interaction volume. This results in a reduced cut region area compared to conventional continuous or long-pulse laser processing, thereby enabling higher density integration of multiple functional devices on the sapphire substrate while maintaining cutting capability.
4Ease of manufacture
If a laser beam is irradiated passing through the nitride layer to process the sapphire substrate, then the substrate can be processed, but heat is generated between the substrate and nitride layer causing defects such as cracks or peeling
Solution Approach 1:
The patent applies periodic action through short pulse laser irradiation, where the laser is delivered in brief pulses with sufficient interval between them. This allows heat to dissipate between pulses, preventing excessive temperature accumulation at the interface between the sapphire substrate and nitride layer, thereby avoiding thermal defects such as cracks or peeling while maintaining substrate processing capability.
Solution Approach 2:
The patent changes the laser processing parameters by using short pulse duration (10-1000 ps) and specific wavelength (343-385 nm), which reduces the total energy deposited and minimizes heat generation. This parameter optimization enables substrate processing while preventing thermal damage at the substrate-nitride layer interface, avoiding cracks and peeling defects.
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
The method effectively suppresses luminance decrease, minimizes fine dust generation, and prevents heat-related defects, enabling high-density integration of functional devices on sapphire substrates.
Implementation Method 1
adjusting a position of a light concentrating unit or the sapphire substrate such that the laser beam is concentrated to the inside of the sapphire substrate through the light concentrating unit
Implementation Method 2
forming a phase transformation area within the sapphire substrate by irradiating the laser beam into the sapphire substrate
Implementation Method 3
making the laser beam irradiated from the laser light source pass through a beam shaping module
Data Source
AI summary
There is provided a laser processing method of a sapphire substrate including preparing a sapphire substrate on which plural stacked portions spaced from each other are formed, irradiating a short pulse laser beam from a laser light source, making the laser beam irradiated from the laser light source pass through a beam shaping module, adjusting a position of a light concentrating unit or the sapphire substrate such that the laser beam is concentrated to the inside of the sapphire substrate through the light concentrating unit, and forming a phase transformation area within the sapphire substrate by irradiating the laser beam into the sapphire substrate. The laser beam is introduced into the sapphire substrate while avoiding an area where the stacked portions are formed on the sapphire substrate, so that the phase transformation area is formed within the sapphire substrate.