Ingot Growth Apparatus with Feedback Control for Silicon Level
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Solution Overview
Problem
In the Czochralski method for growing single-crystal silicon ingots, maintaining a constant level of molten silicon in the crucible is challenging, leading to issues with ingot diameter control, yield, and quality due to uneven replenishment of molten silicon.
Innovation Solution
An ingot growing apparatus with a main crucible, a preliminary crucible for silicon replenishment, a measurement unit to monitor the molten silicon level, and a control unit that adjusts the supply based on measured changes, ensuring a consistent surface level and weight of the ingot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If molten silicon is continuously replenished in the main crucible during ingot growth, then the ingot can be continuously grown, but the level of the molten silicon surface becomes difficult to control, leading to diameter control issues and quality degradation
Solution Approach 1:
The patent implements a feedback control system where a measurement unit continuously monitors the level of the molten silicon surface in the main crucible. Based on the measured level changes, the control unit automatically adjusts the supply rate of molten silicon from the preliminary crucible, creating a closed-loop control system that maintains the surface level within a predetermined range while enabling continuous ingot growth
Solution Approach 2:
The system enables the molten silicon supply process to self-regulate by using the measurement unit to detect surface level changes and automatically adjusting the supply rate through the control unit, eliminating the need for manual intervention and maintaining precise control during continuous operation
2Duration of action of moving object
If the molten silicon surface level is not maintained at a target level, then continuous growth can proceed, but the yield decreases and quality is degraded
Solution Approach 1:
The feedback control mechanism continuously monitors the molten silicon surface level and adjusts the supply rate to maintain it within a predetermined range, ensuring consistent ingot quality and preventing yield degradation while enabling prolonged continuous growth operation
3Device complexity
If manual monitoring and replenishment of molten silicon is performed, then the system is simpler, but the response time is slow and control precision is poor
Solution Approach 1:
The patent replaces manual mechanical monitoring and replenishment operations with an automated system comprising a measurement unit that detects surface level changes and a control unit that automatically adjusts the molten silicon supply rate, significantly improving measurement precision and response time while maintaining reasonable system complexity
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 solution maintains a constant molten silicon level, stabilizes ingot growth, improves yield, and ensures high-quality single-crystal ingots by real-time control of molten silicon supply, preventing yield decreases from supply imbalances.
Implementation Method 1
A reflector which blocks heat from being transferred to the ingot may be provided at an upper side of the main crucible, and the measurement unit may measure the change in the level of the surface of the molten silicon in the main crucible through a change in gap between the surface of the molten silicon in the main crucible and a lower end of the reflector
Implementation Method 2
a preliminary crucible which receives a solid silicon material, melts the solid silicon material, and supplies molten silicon to the main crucible
Data Source
AI summary
Disclosed is an ingot growing apparatus. The ingot growing apparatus according to the embodiment of the present invention includes a growth furnace in which a main crucible is disposed, wherein the main crucible accommodates molten silicon to grow an ingot, a preliminary crucible which receives a solid silicon material, melts the solid silicon material, and supplies molten silicon to the main crucible, a measurement unit which is installed to pass through the growth furnace and measures a change in level of the surface of the molten silicon in the main crucible, and a control unit which controls supply of the molten silicon in the preliminary crucible to the main crucible on the basis of the measured change in the level of the surface of the molten silicon.