Levitated Substrate Conveyance for Moire-Free Laser Crystallization
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Solution Overview
Problem
Existing conveyance apparatuses for laser irradiation in semiconductor manufacturing face challenges in achieving high-speed and stable laser irradiation processes, particularly in ensuring uniform crystallization of silicon films without moire patterns and maintaining substrate stability during the process.
Innovation Solution
A conveyance apparatus that levitates the substrate using a gas ejection mechanism and employs a holding mechanism with a moving mechanism to incline the substrate relative to the line-shaped laser light, allowing for precise control of the irradiation area and preventing moire patterns by adjusting the conveyance direction relative to the laser light's longitudinal direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the substrate is conveyed perpendicular to the line-shaped laser light, then the irradiation process is simplified, but moire patterns occur and crystallization uniformity deteriorates
Solution Approach 1:
The patent applies asymmetry by conveying the substrate at an inclined angle (θ) relative to the laser light direction, rather than perpendicular. This asymmetric conveyance angle prevents the formation of moire patterns while maintaining uniform crystallization across the substrate surface, resolving the contradiction between process simplicity and crystallization quality.
2Productivity
If the substrate is conveyed at high speed, then productivity increases, but substrate stability during irradiation deteriorates
Solution Approach 1:
The patent employs a levitation unit that generates upward force to counteract gravitational effects and stabilize the substrate during high-speed conveyance. This anti-gravity support mechanism maintains substrate stability even at increased irradiation speeds, allowing productivity improvement without sacrificing reliability.
Solution Approach 2:
The system dynamically adjusts the conveyance speed and levitation force to maintain optimal substrate stability during irradiation. By making the conveyance system dynamic rather than static, the patent enables high-speed operation while adapting substrate support conditions to maintain stability throughout the irradiation process.
3Manufacturing precision
If the substrate is levitated over the entire surface, then uniform irradiation is achieved, but device complexity and cost increase
Solution Approach 1:
The levitation unit is segmented into multiple independent modules that can be selectively activated. Rather than levitating the entire substrate surface uniformly, specific regions are levitated as needed during conveyance, achieving uniform irradiation coverage while reducing the overall complexity and cost of the levitation system.
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 configuration enables high-speed and stable laser irradiation, ensuring uniform crystallization of silicon films across the substrate while preventing moire patterns and improving display quality by maintaining substrate stability and optimizing the irradiation process.
Implementation Method 1
a substrate levitation unit configured to levitate the substrate over its top surface
Implementation Method 2
a holding mechanism configured to hold the substrate by absorbing the substrate
Implementation Method 3
irradiate the substrate with line-shaped laser light so that a linear irradiation area is formed therein. As a result, an amorphous silicon film is crystallized and becomes a polysilicon film
Data Source
AI summary
A conveyance apparatus configured to convey a substrate (100) in order to irradiate the substrate (100) with laser light for forming a line-shaped irradiation area (15a) according to an embodiment includes a levitation unit (10) configured to levitate the substrate (100) over its top surface, a holding mechanism (12) configured to hold the substrate (100), and a moving mechanism (13) configured to move the holding mechanism (12) in a direction inclined from a direction perpendicular to a longitudinal direction of the line-shaped laser light in a plan view so as to change an irradiation place of the laser light in the substrate (100).