Laser Lift-Off Beam Shaping for Reliable Substrate Removal
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Solution Overview
Problem
Existing laser lift-off methods for flexible substrates in display device manufacturing face challenges in ensuring reliable removal of carrier substrates without damaging the underlying components, particularly due to variations in energy distribution across the substrate.
Innovation Solution
A laser lift-off apparatus is designed to convert a first beam into a second beam with a specific beam profile, including areas of varying energy density, using a combination of optical components such as a homogenizer, wedge prisms, and Fourier lenses, to precisely control the energy distribution for effective substrate lift-off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform laser beam is used for substrate lift-off, then the processing is simple, but the energy distribution is insufficient for reliable removal without damaging underlying components
Solution Approach 1:
The patent applies local quality by creating a non-uniform beam profile with distinct high-energy and low-energy regions. The beam is shaped to concentrate energy in specific areas (second and fourth quadrants) for effective carrier substrate removal, while maintaining lower energy in other areas to protect underlying components. This spatial variation in energy distribution allows simultaneous achievement of reliable lift-off and component protection.
Solution Approach 2:
The patent uses optical elements (lens and mirror) as intermediaries to transform the uniform laser beam into the desired non-uniform profile. These elements mediate the energy distribution by refracting and reflecting light to create the specific beam shape with high and low energy regions, enabling precise control without directly modifying the laser source.
2Productivity
If high energy is applied to remove carrier substrate, then lift-off effectiveness is improved, but damage risk to active areas increases
Solution Approach 1:
The beam profile is designed with spatially varying energy density, creating high-energy regions (second and fourth quadrants) for effective carrier substrate removal and low-energy regions (first and third quadrants) for protecting underlying components. This local differentiation allows aggressive removal where needed while maintaining gentleness where components are present.
Solution Approach 2:
The laser beam is segmented into multiple energy zones corresponding to different functional requirements. The beam profile divides the irradiation area into distinct high-energy and low-energy regions, allowing independent optimization of removal effectiveness and component protection in different spatial locations.
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
The apparatus improves the reliability of the laser lift-off process by ensuring precise energy application, reducing the risk of damage to active areas with lower energy and effectively removing carrier substrates with higher energy application, thereby enhancing the manufacturing process efficiency.
Implementation Method 1
a homogenizer homogenizing the first beam
Implementation Method 2
a wedge prism refracting at least a portion of the first beam passing through the homogenizer
Implementation Method 3
a laser beam generator generating the first beam
Data Source
AI summary
In a laser lift-off apparatus configured to convert a first beam into a second beam having a width in a short axis direction and a long axis direction, the laser lift-off apparatus includes: a laser beam generator generating the first beam; a homogenizer homogenizing the first beam; and a wedge prism refracting at least a portion of the first beam passing through the homogenizer, wherein a beam profile of the second beam includes a first area and a second area having energy higher than that of the first area.