Preliminary Crucible Silicon Feed Control Using Molten Level Sensing
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Solution Overview
Problem
Existing methods for controlling the supply of molten silicon in a preliminary crucible fail to maintain a constant amount, leading to potential overflow and system shutdowns due to noise interference and imprecise weight measurements, which can cause damage and cost loss.
Innovation Solution
A method for controlling the supply of solid silicon to a preliminary crucible by measuring the height of molten silicon and setting appropriate management ranges, using imaginary lines and level lines to determine the supply amount, ensuring the molten silicon remains within a defined range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If weight measurement is used to control molten silicon supply, then the amount of polysilicon can be adjusted, but measurement precision deteriorates due to noise from crucible rotation and small weight differences
Solution Approach 1:
The patent replaces the mechanical weight measurement system with an optical measurement system. A camera captures images of the molten silicon surface, and image processing algorithms calculate the surface area and infer volume. This substitution eliminates mechanical noise from crucible rotation and provides stable, precise measurements suitable for controlling small weight differences in molten silicon supply.
2Stability of the object's composition
If constant polysilicon supply is controlled by weight, then melting level can be maintained, but overflow detection capability is lost
Solution Approach 1:
The patent introduces an optical field as an intermediary between the molten silicon and the measurement system. The camera captures optical information about the silicon surface, which serves as a mediator to simultaneously determine both the volume (for stability control) and the spatial distribution (for overflow detection). This intermediary enables dual functionality without compromising either stability or detection capability.
3Productivity
If total crucible weight is continuously measured, then supply control is achieved, but noise from movement interferes with precise measurement
Solution Approach 1:
The patent replaces continuous mechanical weight measurement with optical imaging and computational analysis. The camera continuously captures images of the molten silicon surface, and software algorithms process these images to calculate surface area and infer volume in real-time. This approach maintains continuous monitoring capability while eliminating noise from crucible rotation and movement, enabling precise measurement during continuous operation.
Data Source
AI summary
Disclosed is a method for controlling the supply of solid silicon to a preliminary crucible of an ingot growth apparatus for maintaining a constant amount of molten silicon in the preliminary crucible by measuring the height of the molten silicon in the preliminary crucible. The method for controlling the supply of solid silicon to a preliminary crucible of an ingot growth apparatus, according to the present invention, is a method for controlling the supply of solid silicon to the preliminary crucible for supplying molten silicon to a main crucible of the ingot growth apparatus, the method comprising: a management range setting step of setting an appropriate management range of the molten silicon in the preliminary crucible; a height measuring step of measuring the height of the molten silicon contained in the preliminary crucible to confirm whether the molten silicon falls within an appropriate management range of the molten silicon; a supply amount determining step of determining a supply amount of solid silicon to be supplied to the preliminary crucible according to the height measured in the height measuring step; and a step of supplying a predetermined supply amount of solid silicon determined according to the supply amount determining step to the preliminary crucible.