Silicon Crystallization via Reflectivity-Based Energy Density Selection
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Solution Overview
Problem
Existing methods for crystallizing silicon substrates, such as excimer laser annealing, rely on visual inspection for energy density selection, leading to user deviations and increased process time due to the subjective nature of visual evaluation.
Innovation Solution
A method that calculates an Optimum Energy Density (OPED) index by measuring reflectivity across different wavelength ranges and applying weights to average reflectivity values, allowing for the objective selection of optimal energy density for crystallizing silicon substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If visual inspection method is used for energy density selection, then the process is simple to operate, but user deviations occur and measurement precision deteriorates
Solution Approach 1:
The patent replaces the mechanical/subjective visual inspection method with an optical measurement system. A reflectivity measurement device objectively measures the reflectivity of the silicon substrate at different wavelengths, converting the subjective visual evaluation into an objective quantitative measurement. This substitution eliminates user deviations while maintaining ease of operation through automated measurement and calculation of the optimum energy density index.
2Loss of time
If visual inspection method is used for energy density selection, then the process is quick, but reliability deteriorates due to subjectivity
Solution Approach 1:
The patent implements a feedback mechanism where the reflectivity measurement device continuously measures the substrate properties, and the system calculates the optimum energy density index based on these measurements. This closed-loop feedback system ensures consistent and reliable energy density selection by objectively comparing measured values against predetermined thresholds, eliminating the variability inherent in subjective visual inspection while maintaining rapid process timing.
3Measurement precision
If reflectivity measurement across multiple wavelengths is performed, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent segments the spectral measurement into discrete wavelength ranges (blue-based colors and red-based colors) rather than requiring continuous full-spectrum analysis. This segmentation approach maintains high measurement precision by focusing on the critical wavelength regions that differentiate crystallization quality, while reducing device complexity by measuring only these specific bands instead of the entire spectrum. The segmented measurement strategy balances accuracy requirements with practical system implementation.
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 enables quick and accurate selection of energy density, reducing user deviations and enabling mass production of crystallized silicon substrates with improved operational characteristics.
Implementation Method 1
manufacturing a crystallized silicon test substrate that is crystallized by scanning excimer laser annealing beams with different energy densities on respective areas of an amorphous silicon test substrate
Implementation Method 2
irradiating a surface of the crystallized silicon test substrate using a light source in a visible light wavelength range, and measuring reflectivity corresponding to the respective areas of the crystallized silicon test substrate in the visible light wavelength range
Data Source
AI summary
A method for crystallizing a silicon substrate includes manufacturing a crystallized silicon test substrate that is crystallized by scanning excimer laser annealing beams with different energy densities on respective areas of an amorphous silicon test substrate, irradiating a surface of the crystallized silicon test substrate using a light source, and measuring reflectivity corresponding to the respective areas of the crystallized silicon test substrate in a visible light wavelength range, extracting average reflectivities of the respective areas of the crystallized silicon test substrate in wavelength ranges corresponding to respective colors, calculating an optimum energy density (OPED) index per energy density by using a value acquired by subtracting average reflectivity of red-based colors from average reflectivity of blue-based colors, selecting an optimal energy density, and crystallizing an amorphous silicon substrate using the optimal energy density.