Light-Emitting Device Lift-Off Using Two-Step Laser Separation
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Solution Overview
Problem
Existing methods for manufacturing light-emitting devices using laser lift-off techniques suffer from reduced production yield due to cracks in the semiconductor layer during substrate separation.
Innovation Solution
A method involving a two-step laser irradiation process is employed, where a first laser intensity is used to separate the substrate from the semiconductor layer, followed by a second, lower intensity to separate the coating member, reducing stress on the semiconductor layer and minimizing cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single high-intensity laser irradiation is used to separate the substrate from the semiconductor layer, then the separation efficiency is improved, but cracks occur in the semiconductor layer reducing production yield
Solution Approach 1:
The single laser irradiation process is segmented into two sequential steps: first irradiating to separate the substrate from the semiconductor layer, then irradiating again to separate the coating member. This segmentation allows each step to use optimized irradiation conditions, preventing cracks while maintaining separation efficiency
Solution Approach 2:
The first laser irradiation performs a preliminary separation action by detaching the substrate from the semiconductor layer while the coating member remains attached. This preliminary action creates a stable intermediate state that prevents direct stress on the semiconductor layer during complete separation
2Device complexity
If high laser irradiation intensity is applied to separate both substrate and coating member simultaneously, then the manufacturing process is simplified, but excessive stress causes semiconductor layer cracking
Solution Approach 1:
The separation process is divided into two distinct irradiation steps with different intensity requirements. The first step uses higher intensity for substrate separation, while the second step uses lower intensity for coating member separation, preventing excessive stress accumulation
Solution Approach 2:
The laser irradiation is applied periodically in two distinct phases rather than continuously. The first phase separates the substrate, then a second phase separates the coating member. This periodic application allows stress relaxation between phases, preventing semiconductor layer damage
3Ease of operation
If the coating member is removed first before substrate separation, then the substrate access is improved, but the semiconductor layer undergoes unnecessary stress reducing yield
Solution Approach 1:
The substrate separation is performed as a preliminary action before coating member removal. This establishes a stable configuration where the semiconductor layer is already detached from the substrate, minimizing subsequent stress during coating member separation
Solution Approach 2:
The conventional sequence is inverted: instead of removing the coating member first to access the substrate, the substrate is separated first while the coating member remains in place. This inversion protects the semiconductor layer from stress while still achieving substrate access
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 enhances the production yield by effectively reducing the likelihood of semiconductor layer cracks, thereby improving the manufacturing efficiency of light-emitting devices.
Implementation Method 1
a stacked body that includes a substrate and a semiconductor layer formed on the substrate is irradiated with laser light to separate the substrate from the semiconductor layer
Implementation Method 2
the interface between the substrate and the semiconductor layer is irradiated with laser light, so that the semiconductor layer can be decomposed at the interface
Implementation Method 3
separating the semiconductor layer and the coating member from the substrate by irradiating the stacked body from a side of the first surface of the substrate with a laser light
Data Source
AI summary
A method for manufacturing a light-emitting device includes preparing and separating. In the preparing, a stacked body is prepared. The stacked body includes a substrate, a semiconductor layer, and a coating member. The substrate includes first and second surfaces. The second surface includes first and second regions. The separating includes first and second processes. In the first process, the substrate is separated from the semiconductor layer by irradiating the first region with a laser light of a first irradiation intensity. In the second process, the substrate is separated from the coating member by irradiating at least the second region with the laser light of a second irradiation intensity. The second irradiation intensity is lower than the first irradiation intensity. The second process is performed after the first process.