Poly-Silicon Grain Size Measurement via SEM Interface Diagrams
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Solution Overview
Problem
Current methods for measuring the size of crystal grains in poly-silicon thin films do not accurately reflect their geometrical characteristics, leading to ineffective fabrication processes for poly-silicon thin film transistors with superior electrical performance.
Innovation Solution
A method and apparatus that involve obtaining grain morphology images using scanning electron microscopy, drawing grain interface diagrams, and measuring transverse and longitudinal sizes of crystal grains at multiple evenly spaced points to determine accurate average sizes, which are then used to evaluate and adjust the excimer laser annealing process parameters for improved film fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional crystal grain size measurement methods are used, then the measurement process is simple, but the measurement precision is insufficient and does not accurately reflect geometrical characteristics
Solution Approach 1:
The patent divides the crystal grain measurement into multiple segments: obtaining grain morphology images, drawing grain interface diagrams, selecting multiple measurement points within each grain, measuring at each point, and calculating average values. This segmentation transforms a single complex measurement into multiple simpler, more accurate sub-measurements that collectively improve precision while maintaining manageable process complexity.
Solution Approach 2:
The patent transitions from traditional single-point or single-dimension measurement to multi-point, multi-dimensional measurement by selecting multiple measurement points within crystal grains and measuring both transverse and longitudinal sizes. This dimensional expansion captures the geometrical characteristics more comprehensively, improving measurement accuracy without excessive complexity.
2Measurement precision
If multiple measurement points are used to improve accuracy, then the measurement precision improves, but the measurement time increases
Solution Approach 1:
The patent performs preliminary actions by first obtaining grain morphology images and drawing grain interface diagrams before actual measurement. This preliminary structuring of the data allows for efficient selection of measurement points and streamlined measurement processes, reducing the time penalty associated with multiple measurement points while maintaining high precision.
Solution Approach 2:
The patent creates a grain interface diagram as a simplified copy or representation of the actual grain morphology. This diagram serves as a working model that can be measured efficiently without repeatedly accessing the complex original morphology images, thus reducing measurement time while preserving measurement accuracy through the use of multiple points on the diagram.
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 allows for the accurate assessment of crystal grain sizes, guiding the fabrication process to produce poly-silicon thin films with enhanced electrical performance by reflecting the geometrical characteristics of the grains, thereby improving transistor performance.
Implementation Method 1
imaging the crystalline region of the crystal using a scanning electron microscope to obtain the grain morphology image of the crystalline region
Implementation Method 2
an active layer in the p-Si thin film transistor is typically a poly-silicon thin film formed after an excimer laser annealing process is performed on an a-Si thin film
Implementation Method 3
an excimer laser annealing process is performed on an a-Si thin film
Data Source
AI summary
The disclosure discloses a method and apparatus for measuring a size of a crystal grain, and a method for fabricating a poly-silicon thin film. The method for measuring the size of the crystal grain includes: obtaining a grain morphology image of a crystalline region of a crystal, and drawing a grain interface diagram according to the grain morphology image; measuring at least one crystal grain in the grain interface diagram, and determining a transverse size and a longitudinal size of each measured crystal grain; and determining a transverse size and a longitudinal size of a crystal grain of the crystal according to the transverse size and the longitudinal size of each measured crystal grain.