Optical Wafer Laser Buffer Layer Breaking
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Solution Overview
Problem
During the transfer of an optical device wafer to a transfer substrate, there is a risk of the epitaxy substrate dropping off, causing damage to either the epitaxy substrate or the transfer substrate, due to the application of a laser beam that breaks the buffer layer.
Innovation Solution
An optical device wafer processing method involving a pulsed laser beam with specific energy densities and application patterns to completely break the buffer layer over the optical device area while incompletely breaking it in the peripheral marginal area, maintaining partial binding to prevent substrate drop-off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser beam is applied to break the buffer layer completely, then the optical device layer can be transferred to the transfer substrate, but the epitaxy substrate may drop off causing damage
Solution Approach 1:
The patent applies different laser beam energy densities to different regions of the buffer layer. The optical device area receives a first energy density (0.25-1.0 J/cm²) that completely breaks the buffer layer, while the peripheral marginal area receives a second energy density (0.1-0.15 J/cm²) that incompletely breaks the buffer layer, maintaining partial bonding to prevent substrate drop-off during transport.
2Productivity
If the buffer layer is completely broken, then the optical device layer can be successfully transferred, but the epitaxy substrate loses support and may drop off
Solution Approach 1:
The patent divides the buffer layer into two functional segments: the optical device area where complete buffer layer breaking enables efficient transfer, and the peripheral marginal area where incomplete breaking maintains substrate support. This segmentation allows simultaneous achievement of transfer efficiency and substrate stability.
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 effectively transfers the optical device layer to the transfer substrate without the epitaxy substrate dropping off, ensuring the integrity of both substrates during processing.
Implementation Method 1
applying a pulsed laser beam having a wavelength having transmissivity to the epitaxy substrate and having absorptivity to the buffer layer from the back side of the epitaxy substrate to the buffer layer, thereby breaking the buffer layer
Implementation Method 2
a pulsed laser beam having a wavelength having transmissivity to the epitaxy substrate and having absorptivity to the buffer layer
Data Source
AI summary
An optical device wafer processing method for processing an wafer having an epitaxy substrate and an optical device layer formed on the front side of the epitaxy substrate through a buffer layer. The buffer layer is to be broken in the condition where the optical device layer is bonded through a bonding metal layer to a transfer substrate. The method includes a buffer layer breaking step of applying a pulsed laser beam having a wavelength having transmissivity to the epitaxy substrate and having absorptivity to the buffer layer from the back side of the epitaxy substrate to the buffer layer, thereby breaking the buffer layer. The buffer layer breaking step includes a first laser beam applying step of completely breaking the buffer layer corresponding to an optical device area and a second laser beam applying step of incompletely breaking the buffer layer corresponding to a peripheral marginal area.