Chemical Lift-Off Chamber Layout for Clean LED Thin-Film Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for separating semiconductor light-emitting devices from substrates, such as the laser lift-off process, can damage the GaN-based LED thin films and leave behind gallium droplets, while chemical lift-off processes face challenges in recovering the devices efficiently.
Innovation Solution
A chemical lift-off device and method utilizing a first chamber with a chemical solution for partial separation, a cleaning bath with deionized water for contaminant removal, and a second chamber with a chemical solution sprayer for complete separation, accompanied by a recovery assembly to efficiently recover the devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser lift-off process is used to separate GaN-based LED thin film from substrate, then separation is achieved, but heat damage occurs to the thin film and gallium droplets remain
Solution Approach 1:
The patent replaces the laser lift-off process (thermal/mechanical system) with a chemical lift-off process using KOH solution. The chemical solution selectively etches the AlGaN sacrificial layer at the interface between the GaN-based LED thin film and silicon substrate, achieving separation without thermal damage or gallium droplet formation. This substitution of mechanical/thermal method with chemical method resolves the harmful effects while maintaining separation effectiveness.
Solution Approach 2:
The patent changes the separation mechanism from thermal (laser) to chemical (KOH solution etching). By controlling parameters such as KOH solution concentration (e.g., 5-20%), temperature (e.g., 20-80°C), and treatment time, the process achieves complete separation of the GaN-based LED thin film from the substrate without causing heat damage or leaving gallium droplets, thus improving separation quality while eliminating harmful effects.
2Object-affected harmful factors
If chemical lift-off process is used to separate GaN-based LED thin film from silicon substrate, then separation is achieved without heat damage, but device recovery is difficult
Solution Approach 1:
The patent segments the chemical lift-off process into distinct stages: (1) partial separation in a first chamber with KOH solution to remove the sacrificial layer, (2) cleaning in a first cleaning bath to remove chemical residues, and (3) complete separation in a second chamber with additional KOH solution. This segmentation allows for controlled separation and facilitates easier device recovery by preventing complete disintegration while achieving separation, thus resolving the difficulty in device recovery.
Solution Approach 2:
The patent introduces a sacrificial layer (AlGaN layer) as an intermediary between the GaN-based LED thin film and the silicon substrate. This sacrificial layer is selectively removed by KOH solution, enabling separation of the thin film from the substrate without direct chemical attack on the LED structure itself. The intermediary layer protects the device integrity during separation and simplifies recovery by allowing the thin film to be cleanly detached and collected.
3Ease of operation
If multi-chamber chemical lift-off device is used for complete separation and recovery, then device recovery is facilitated, but system complexity increases
Solution Approach 1:
The patent designs the multi-chamber chemical lift-off device where each chamber serves multiple functions: the first chamber performs partial separation and initial cleaning, the second chamber completes separation and provides final cleaning. The KOH solution circulates through both chambers, and the same basic chamber structure is replicated with minor modifications. This multi-functionality reduces overall system complexity by using standardized components and processes rather than requiring entirely separate systems for each function.
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 the risk of damage to the LED thin films, shortens the separation process, and facilitates effective recovery of semiconductor light-emitting devices, improving the efficiency and ease of the lift-off process.
Implementation Method 1
a first bath containing a first chemical solution and configured to receive a semiconductor light-emitting device on a substrate, such that the semiconductor light-emitting device is partially separated from the substrate by being submerged in the first chemical solution
Implementation Method 2
a second chamber including a separator including a chemical solution sprayer configured to spray a second chemical solution toward the semiconductor light-emitting device that is partially separated from the substrate, such that the semiconductor light-emitting device is completely separated from the substrate by being sprayed with the second chemical solution
Data Source
AI summary
A chemical lift-off device includes a first chamber including a first bath containing a first chemical solution and configured to receive a semiconductor light-emitting device on a substrate, such that the semiconductor light-emitting device is partially separated from the substrate by being submerged in the first chemical solution, a cleaning bath containing deionized water and configured to receive the semiconductor light-emitting device that is partially separated from the substrate, and a second chamber including a separator including a chemical solution sprayer configured to spray a second chemical solution toward the semiconductor light-emitting device that is partially separated from the substrate, such that the semiconductor light-emitting device is completely separated from the substrate by being sprayed with the second chemical solution and a recovery assembly provided at a lower portion of the separator and configured to recover the semiconductor light-emitting device that is completely separated from the substrate.