GaN Substrate Nitride Deposit Removal via Laser Ablation
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Solution Overview
Problem
The existing methods for producing GaN independent substrates face inefficiencies in removing nitride deposits from the periphery of GaN crystal bodies and GaAs substrates, requiring manual processing and leading to productivity issues and potential wafer breakage.
Innovation Solution
A method involving peripheral processing using grinding stones with varying stiffness and oscillating motions to remove nitride deposits, followed by etching to separate the substrate from the GaN crystal body, ensuring efficient removal and shaping of the GaN crystal body for wafer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual processing is used to remove nitride deposits from the periphery of GaN crystal body and GaAs substrate, then complete removal can be achieved, but processing time is excessive and productivity is low
Solution Approach 1:
The patent replaces manual mechanical processing with automated laser beam processing to remove nitride deposits. The laser beam systematically scans and ablates the deposit material, achieving complete removal while dramatically reducing processing time and increasing productivity compared to manual methods.
Solution Approach 2:
The patent utilizes laser-induced phase transition of the nitride deposit material from solid to vapor/plasma state through ablation. The laser beam delivers concentrated energy that rapidly heats and vaporizes the deposit, enabling efficient removal without mechanical contact and minimizing processing time.
2Ease of operation
If manual processing is used to remove nitride deposits, then flexibility in handling can be maintained, but risk of wafer breakage increases
Solution Approach 1:
The patent replaces manual mechanical handling with automated laser processing and robotic positioning systems. This eliminates human contact with the fragile GaN crystal body and GaAs substrate during the critical deposit removal phase, thereby reducing the risk of accidental breakage while maintaining operational flexibility through programmable control.
Solution Approach 2:
The patent introduces a laser beam as an intermediary tool that remotely removes nitride deposits without requiring direct mechanical contact with the wafer. This non-contact approach acts as a mediator between the processing system and the fragile substrate, eliminating the risk of mechanical damage while achieving the desired removal效果.
3Manufacturing precision
If conventional etching methods are used to remove GaAs substrate after GaN crystal body growth, then substrate removal can be achieved, but projecting nitride deposits remain on the periphery
Solution Approach 1:
The patent applies laser processing to remove nitride deposits from the periphery of the GaN crystal body and GaAs substrate before the substrate etching step. This preliminary action prevents the formation of projecting deposits that would otherwise remain after conventional etching, ensuring a clean final product without requiring additional post-processing.
Solution Approach 2:
The patent inverts the conventional sequence by removing nitride deposits before substrate etching rather than after. This reverse approach ensures that when the GaAs substrate is subsequently removed by etching, no projecting nitride deposits remain on the periphery of the GaN crystal body, eliminating the need for additional cleanup operations.
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 significantly reduces processing time, enhances productivity, and minimizes the risk of wafer breakage by systematically removing nitride deposits, allowing for the efficient production of GaN substrates with improved precision and efficiency.
Implementation Method 1
The method comprises the steps of: processing the periphery of the substrate and GaN crystal body with a grinding wheel to remove the nitride deposit
Implementation Method 2
after the peripheral processing, separating the substrate from the GaN crystal body to form a GaN independent substrate
Data Source
AI summary
A method of producing a separated GaN crystal body grown by vapor phase epitaxy on a substrate made of material different from GaN is provided. In this method, a nitride deposit is formed during the growth on a periphery of the substrate and GaN crystal body. The present method comprises the steps of: processing the periphery of the substrate to remove the nitride deposit; and, after the peripheral processing, separating the substrate from the GaN crystal body to make the substrate and the GaN crystal body independent of each other.