Laser Crystallization System for Uniform Polycrystalline Silicon
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Solution Overview
Problem
Existing laser crystallization methods face challenges in achieving uniform crystallization of polycrystalline silicon layers due to non-uniform semiconductor layer thickness, leading to non-uniform resistance in TFTs and increased processing time for deposition map measurement.
Innovation Solution
A laser crystallization system that splits output laser light into two beams, one for crystallization and the other for surface information detection, allowing for real-time adjustment of crystallization energy based on thickness variations, eliminating the need for a separate deposition map measurement process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a separate deposition map measurement process is performed to identify semiconductor layer thickness before laser crystallization, then the crystallization uniformity can be improved, but the total processing time increases and device complexity increases
Solution Approach 1:
The patent combines the deposition map measurement function and laser crystallization function into a single integrated laser system. The laser beam is split into two paths: one for measuring thickness via reflection time and intensity, and another for crystallization. This merging eliminates the need for separate measurement equipment and processes, reducing total processing time while maintaining crystallization uniformity through real-time thickness-based energy adjustment.
Solution Approach 2:
The laser system is designed to perform multiple functions: it can measure semiconductor layer thickness by analyzing reflection characteristics and simultaneously perform crystallization by delivering controlled laser energy. This multi-functionality allows a single device to replace what would traditionally require separate measurement and processing equipment, streamlining the workflow and reducing overall processing time.
2Productivity
If laser beam intensity is not adjusted according to semiconductor layer thickness variations, then the processing speed is maintained, but the crystallization uniformity deteriorates leading to non-uniform TFT resistance
Solution Approach 1:
The system dynamically adjusts laser beam energy based on real-time thickness measurements. The controller modifies laser parameters (such as energy density or pulse duration) according to the detected thickness variations in different regions of the semiconductor layer. This dynamic adaptation ensures uniform crystallization results even when processing speeds are maintained, preventing non-uniform TFT resistance without sacrificing productivity.
Solution Approach 2:
The system implements a feedback mechanism where the measured thickness information from the deposition map is fed back to the laser control system. Based on this feedback, the laser energy delivery is automatically adjusted for each region to compensate for thickness variations. This closed-loop control ensures that crystallization uniformity is maintained while preserving processing speed, as no manual intervention or re-measurement is required.
3Device complexity
If the laser system is simplified without thickness measurement capability, then device complexity is reduced, but the ability to achieve uniform crystallization on non-uniform layers is lost
Solution Approach 1:
The patent merges the measurement and processing functions into a single laser system, eliminating the need for separate measurement equipment. The laser itself performs both thickness measurement (through reflection analysis) and crystallization, reducing device complexity while maintaining the capability to achieve uniform crystallization on non-uniform layers through real-time energy adjustment based on measured thickness.
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 enhances the uniformity of polycrystalline silicon layer crystallization, simplifies the process, and improves productivity by integrating surface information collection and energy adjustment in a single operation.
Implementation Method 1
a laser beam may provide energy for crystallization of the amorphous semiconductor layer
Implementation Method 2
a thermal annealing method using furnace annealing, a rapid annealing method, a laser annealing method
Implementation Method 3
an optical unit configured to split the output laser light into a first laser light and a second laser light
Data Source
AI summary
A laser crystallization system, including an output unit configured to generate output laser light, an optical unit configured to split the output laser light into a first laser light and a second laser light, and to process the first laser light to have a crystallization energy density, a moving unit configured to move a target object to be irradiated with the first laser light and the second laser light, a detection unit configured to detect surface information of the target object utilizing the second laser light, and an input unit configured to receive the detected surface information and to transmit a control signal to the output unit and the moving unit, wherein the laser crystallization system is configured to detect the surface information of the target object and to crystallize the target object utilizing only the output laser light.