Single Crystal Pulling Apparatus Water Cooling Protection
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Solution Overview
Problem
Existing single crystal pulling apparatuses face issues with water piping damage due to falling or ruptured crystals, thermal stress, and vapor explosions caused by local corrosion at dissimilar metal joints, as well as poor thermal conductivity and high costs associated with current cooling solutions.
Innovation Solution
The apparatus employs supporting arms to protect water piping from crystal falls and ruptures, uses copper for high thermal conductivity in water-cooling means and stainless steel for piping segments, and positions dissimilar metal joints outside the chamber to prevent corrosion and vapor explosions, with a water channel design that directs cooling water downward and upward to discharge bubbles effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water piping is provided without protection within the chamber, then the cooling function can be implemented, but the water piping may be broken or damaged by falling or ruptured single crystals
Solution Approach 1:
A protective cover is introduced as an intermediary element between the single crystal and the water piping. The cover prevents direct contact between the falling crystal and the piping while still allowing the cooling function to operate, thus resolving the contradiction between implementing cooling and preventing piping damage.
2Reliability
If water-cooling means and water piping are made of dissimilar metals, then cooling performance and mechanical strength can be optimized, but local corrosion may occur at the joint
Solution Approach 1:
The joint between dissimilar metals is extracted from the chamber environment. By positioning the joint outside the chamber where it is not exposed to the corrosive atmosphere, the harmful local corrosion is prevented while still allowing the use of dissimilar metals for optimized cooling performance and mechanical strength.
3Reliability
If cooling water flows upward in the water-cooling means, then bubble discharge is facilitated, but cooling efficiency may be reduced
Solution Approach 1:
The water-cooling means is divided into different sections with different flow directions. The lower section has upward flow for bubble discharge, while the upper section has downward flow for efficient cooling. This local differentiation of flow quality resolves the contradiction between bubble discharge efficiency and cooling efficiency.
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 configuration enhances the safety and efficiency of single crystal pulling by preventing water piping damage, reducing the risk of vapor explosions, and maintaining effective cooling performance while minimizing costs and corrosion risks.
Implementation Method 1
a water-cooling means for cooling the single crystal while it is pulled
Implementation Method 2
a method for increasing the diameter of the single crystal or/and a method for increasing a pull rate of the single crystal are generally employed to improve the single crystal production efficiency. Among these, a method for increasing the single crystal pull rate comprises disposing a heat-shielding member around the single crystal which is being pulled up from the silicon melt, so that the radiant heat emitted from the melt in the crucible and from a heater disposed outside the crucible is shut off by the heat-shielding member
Data Source
AI summary
A single crystal pulling apparatus comprises: a chamber; a crucible disposed within the chamber for containing a melt; a water-cooling means disposed within the chamber in such a manner as surrounding a single crystal pulled up from the melt in the crucible; water piping for feeding cooling water to and discharging the same from the water-cooling means; and supporting arms connected to the chamber for supporting the water-cooling means, wherein the supporting arms are disposed between the single crystal and the water piping. According to this configuration, the supporting arms can prevent the water piping from being damaged in the event of fall and collapse of the single crystal due to failure of the seed neck portion or in the event of rupture of the single crystal due to thermal stress, for instance.