Crucible Isolating Layer Spraying with Temperature Feedback
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Solution Overview
Problem
Conventional methods for manufacturing isolating layers on crucibles for silicon ingot production face challenges in achieving uniformity and desired thickness, leading to cracks and reduced quality and yield of silicon ingots due to thermal expansion differences and impurity diffusion.
Innovation Solution
A method using a temperature-sensing spraying device that adjusts the spraying parameters based on temperature differences measured before and after applying the slurry to ensure the isolating layer is within a predetermined temperature range, ensuring uniformity and thickness, thereby preventing cracks and improving ingot quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spraying method is used to form isolating layer, then the crucible can be protected from molten silicon adhesion, but the thickness and uniformity of the isolating layer cannot be controlled, leading to cracks
Solution Approach 1:
The patent employs temperature sensing feedback during the spraying process. Temperature sensors detect the temperature of the crucible inner wall in real-time, and this information is fed back to the control system which adjusts spraying parameters (such as spraying speed, distance, or slurry flow rate) to maintain the temperature within a predetermined range, ensuring uniform isolating layer formation without cracks
Solution Approach 2:
The patent changes the control parameter from simple spraying duration or distance to temperature-based control. By monitoring temperature changes during spraying and adjusting spraying parameters accordingly, the system achieves precise control over isolating layer thickness and uniformity, preventing crack formation
2Duration of action of stationary object
If the isolating layer is not uniform or has cracks, then the crucible life is extended, but the silicon ingot quality and yield decrease due to impurity diffusion
Solution Approach 1:
The temperature sensing feedback system ensures the isolating layer is formed uniformly and without defects by continuously monitoring and adjusting spraying parameters. This prevents cracks and non-uniformities that would otherwise allow impurity diffusion, thereby maintaining silicon ingot quality while extending crucible life through proper isolating layer formation
3Manufacturing precision
If complicated measurement method is used to measure inner wall of crucible, then the spraying accuracy can be improved, but the manufacturing time increases significantly
Solution Approach 1:
The patent replaces complicated mechanical measurement systems with a temperature-based sensing system. Instead of physically measuring and mapping the crucible inner wall geometry, the system uses temperature sensors to detect the state of the inner wall during spraying, which is then used to control the spraying process. This substitution dramatically reduces measurement time while maintaining or improving spraying accuracy
Solution Approach 2:
The crucible itself serves as the measurement reference by its temperature response to spraying. The temperature changes of the crucible inner wall during spraying provide real-time feedback about the isolating layer formation, eliminating the need for separate, time-consuming measurement steps. The system uses the crucible's own thermal properties as the measurement mechanism
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
The method effectively maintains uniformity and thickness of the isolating layer within a 6° C. to 12° C. temperature difference range, significantly reducing the crack probability of silicon ingots to 0.01% and extending crucible life, while ensuring consistent quality and yield.
Implementation Method 1
a temperature sensing unit electrically connected to the processing unit... measuring an inner wall of the crucible to get a first temperature by the temperature sensing unit; measuring the isolating layer formed on the inner wall of the crucible to get a second temperature by the temperature sensing unit
Implementation Method 2
heating the crucible, and then measuring an inner wall of the crucible to get a first temperature by the temperature sensing unit
Data Source
AI summary
A method for manufacturing an isolating layer onto a crucible includes the steps as follows: providing a spraying device for the following spraying steps; heating the crucible and measuring the heated crucible to get a first temperature; spraying a slurry on the inner wall of the crucible to form an isolating layer by a spraying unit with a predetermined spraying manner; measuring the isolating layer to get a second temperature; obtaining a value for the difference between the first and second temperatures and judging whether the difference value in a within predetermined difference scope or not, in which the predetermined difference scope is about 6° C.˜12° C.; when the difference value is not in the predetermined difference scope, adjusting the predetermined spraying manner; when the difference value is in the predetermined difference scope, implementing the above spraying steps to the crucible.