LED Wafer Bonding with Laser Release for Clean High-Temp Processing
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Solution Overview
Problem
Current methods for supporting semiconductor layers during LED manufacturing, such as organic bonding, face issues with stress, delamination, and contamination, particularly when high temperature and basic oxidizing processes are involved, limiting their compatibility with certain processing steps.
Innovation Solution
The use of a transparent support wafer with a laser lift-off release layer and an inorganic bonding layer, which forms an inorganic processing layer when bonded to the growth wafer, allowing for temporary mechanical support without inducing significant stress and enabling the removal of the growth wafer while preserving the device layer for further processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If organic bonding materials are used to temporarily hold the semiconductor layers to a support wafer, then the bonding process is compatible with basic oxidizing chemistries, but the organic materials exhibit poor chemical inertness to basic oxidizing process steps and high temperatures
Solution Approach 1:
The patent introduces an inorganic bonding layer as an intermediary between the support wafer and the semiconductor device layers. This inorganic bonding layer serves as a mediator that provides both mechanical support and chemical stability, enabling the system to withstand basic oxidizing process steps and high temperatures while maintaining temporary bonding functionality during manufacturing.
Solution Approach 2:
The patent changes the material parameter from organic bonding materials to inorganic bonding materials. This parameter change transforms the chemical properties of the bonding layer, providing resistance to basic oxidizing chemistries and high temperatures while maintaining the necessary bonding characteristics for temporary support during device fabrication.
2Reliability
If oxide bonds are used for support, then the bonds are inert to basic oxidizing chemistries and compatible with high temperatures, but the bonds are permanent and preclude processing flows that require a temporary bond
Solution Approach 1:
The patent segments the bonding system into distinct functional layers: a support wafer, an inorganic bonding layer, a laser release layer, and the semiconductor device layers. This segmentation allows the inorganic bonding layer to provide chemical stability while the laser release layer provides temporary bonding functionality, enabling both permanent chemical resistance and temporary mechanical support.
Solution Approach 2:
The patent introduces a laser release layer as an intermediary between the inorganic bonding layer and the semiconductor device layers. This intermediary layer provides the temporary bonding capability needed for processing, while the underlying inorganic bonding layer maintains chemical inertness. The laser release layer can be selectively removed to release the device layers, enabling temporary bonding workflows.
3Ease of operation
If organic materials are used for bonding, then the bonding provides temporary support, but the organic materials are undesirable contaminants in processing tools and can cause delamination
Solution Approach 1:
The patent changes the material composition parameter from organic to inorganic bonding materials. This parameter change eliminates the contamination issues associated with organic materials in processing tools while maintaining the temporary support capability through the layered structure of inorganic bonding layer plus laser release layer.
Solution Approach 2:
The patent introduces an inorganic bonding layer as an intermediary that replaces organic bonding materials. This inorganic layer serves as a clean, non-contaminating intermediary that provides stable bonding during processing without introducing organic contaminants into the manufacturing environment, while the laser release layer maintains the temporary bonding functionality.
4Productivity
If the growth substrate is removed before completion of processing, then the device layers can be supported by a support material, but the removal of the temporary wafer must not induce significant damage
Solution Approach 1:
The patent introduces an inorganic bonding layer as an intermediary between the growth substrate and the semiconductor device layers. This intermediary layer allows for clean separation and removal of the growth substrate without damaging the device layers, as the bonding interface is designed to break at the bonding layer rather than at the device layer interface.
Solution Approach 2:
The patent segments the wafer structure into distinct layers with defined separation interfaces. The inorganic bonding layer is positioned as a separable interface layer that can be cleanly removed or broken away, allowing the growth substrate to be removed without inducing damage to the device layers. This segmentation creates a controlled failure plane that protects the device layers.
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 reduces stress on thin film device layers, prevents delamination, and maintains a clean surface, making it suitable for high-temperature and basic oxidizing process steps, while being compatible with organic bonding and allowing for the reuse of the support wafer.
Implementation Method 1
bonding the inorganic bonding layer on the transparent support wafer with the matching inorganic bonding layer on the growth wafer to form an inorganic processing layer
Implementation Method 2
separating the processed device layer from the transparent support wafer, leaving the inorganic processing layer on a second side of the processed device layer
Data Source
AI summary
Methods of manufacturing a light emitting diode (LED) comprising bonding a transparent support wafer to a growth wafer are described. The transparent support wafer has a laser lift-off (LLO) release layer and inorganic bonding layer. The growth wafer has a matching inorganic bonding layer which is bonded to the inorganic bonding layer of the transparent support wafer. After processing, the LLO release layer is removed, separating the transparent support wafer and device wafer, and making the transparent support wafer available for reuse.