Laser Crystallization Beam Overlap for Uniform Polysilicon Growth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laser crystallization methods face challenges in achieving uniform crystallization and high crystallization margin due to issues with the long axis angular distribution of the line beam, which affects the quality of polysilicon formation and subsequently the performance of thin film transistors in display devices.
Innovation Solution
A laser crystallization apparatus comprising multiple laser generators, attenuators, and an optical module that adjusts the energy intensity and direction of laser beams to minimize the long axis angular distribution, ensuring uniform energy distribution and improved crystallization by overlapping attenuated and maintained laser beams to form a line beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional laser beam is used for crystallization, then the crystallization process can be performed, but the long axis angular distribution is large which reduces crystallization margin and uniformity
Solution Approach 1:
The laser beam is divided into multiple sub-beams (first laser beam, second laser beam, etc.) that are separately controlled and then overlapped. Each sub-beam can be independently adjusted in terms of energy intensity and angular distribution, allowing the final composite beam to have reduced long axis angular distribution while maintaining uniform energy distribution across the crystallization area.
Solution Approach 2:
Different regions of the laser beam are given different properties through the use of multiple attenuators. The first attenuator adjusts energy intensity of one sub-beam while the second attenuator maintains or adjusts energy intensity of another sub-beam. This allows local optimization of beam characteristics to achieve overall improved crystallization uniformity and reduced angular distribution.
2Manufacturing precision
If multiple laser beams are overlapped to reduce angular distribution, then crystallization uniformity improves, but the device complexity increases
Solution Approach 1:
The multiple laser generators and attenuators serve dual functions: they individually control specific beam parameters (energy intensity, angular distribution) and collectively contribute to the final overlapped beam that achieves uniform crystallization. This multi-functionality justifies the increased device complexity by providing precise control over crystallization quality.
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 enhances crystallization margin and uniformity, resulting in polysilicon crystal particles of uniform size and improved characteristics for thin film transistors, thereby enhancing the image quality of display devices.
Implementation Method 1
Polysilicon may be formed by depositing amorphous silicon and then crystallizing the amorphous silicon. Amorphous silicon may be crystallized into polysilicon by heating the amorphous silicon in a hot furnace or irradiating the amorphous silicon with a laser.
Data Source
AI summary
A laser crystallization apparatus includes a plurality of laser generators which generate a plurality of laser beams, a plurality of attenuators which adjust energy intensity of the plurality of laser generators, and an optical module which overlap outputs of the plurality of attenuators to output a line beam. A first attenuator of the plurality of attenuators attenuates the energy intensity of the corresponding laser beam, and a second attenuator of the plurality of attenuators maintains the energy intensity of the corresponding laser beam.