Large-Outer-Diameter Quartz Crucible Vacuum Arc Electrode Configuration
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Solution Overview
Problem
The manufacturing of large-size quartz crucibles for Czochralski single crystals faces challenges in achieving uniform heating and high-quality crucible formation due to inadequate temperature distribution and impurity issues, particularly at the bottom of the crucible, which affects the quality of monocrystalline silicon production.
Innovation Solution
A vacuum arc method using an electrode bundle composed of 2N+1 electrodes, where one central main electrode and 2N auxiliary electrodes are equidistantly distributed, connected to industrial three-phase power, generating high-temperature arcs for improved fusion and polishing of the crucible blank, ensuring a higher glass transition degree and reduced impurity content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If three electrodes are used to generate arc for melting quartz sand, then the manufacturing process is simple, but the temperature is insufficient for large-size crucibles and the bottom polishing is inadequate
Solution Approach 1:
The electrode system is segmented into multiple electrodes (2N+1 configuration) arranged in specific patterns. Instead of using a single or three electrodes, the patent divides the heating function across multiple electrodes positioned at different locations, allowing independent control of temperature zones and achieving both high central temperature and adequate bottom temperature simultaneously.
Solution Approach 2:
The patent transitions from a simple three-electrode configuration to a multi-dimensional electrode arrangement with 2N+1 electrodes positioned in specific geometric patterns. This dimensional expansion allows the arc to reach different regions of the crucible blank more effectively, particularly improving bottom heating and polishing while maintaining manufacturing feasibility.
2Manufacturing precision
If fusion time is prolonged to improve crucible quality, then the temperature distribution improves, but the energy consumption increases significantly
Solution Approach 1:
The multi-electrode configuration enables continuous and uniform heating action across the entire crucible blank surface and bottom. By having multiple arc sources operating simultaneously, the system maintains optimal temperature distribution throughout the fusion process, achieving high-quality glass transition and impurity removal without requiring prolonged heating times that would waste energy.
Solution Approach 2:
The patent changes the key parameter from electrode number (from 3 to 2N+1) to fundamentally alter the temperature distribution pattern. This parameter change enables rapid achievement of optimal fusion conditions, reducing the required fusion time and energy consumption while maintaining or improving crucible quality through better temperature uniformity.
3Temperature
If the number of electrodes is increased to improve temperature distribution, then the heating coverage increases, but the device complexity increases
Solution Approach 1:
The patent employs asymmetric electrode positioning patterns (such as one electrode at the center and others arranged asymmetrically around it) rather than completely symmetric arrangements. This asymmetric configuration optimizes the arc distribution to specifically address the bottom heating problem while maintaining manageable system complexity through deliberate, non-uniform placement strategies.
Solution Approach 2:
The 2N+1 electrode configuration serves multiple functions simultaneously: it provides comprehensive heating coverage, achieves bottom polishing, maintains central temperature, and ensures uniform glass transition. This multi-functional electrode system resolves the contradiction by making the electrode arrangement itself perform multiple critical tasks, reducing the need for additional separate systems.
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 achieves a higher central temperature, better polishing of the crucible bottom, and improved quality, addressing the issues of inadequate bottom temperature and insufficient polishing, resulting in a higher purity and yield of the quartz crucible, suitable for large-size crucible production.
Implementation Method 1
releasing a high-temperature arc with an electrode bundle composed of 2N+1 electrodes to fuse the crucible blank
Implementation Method 2
molten at 3,000° C. or above through a high-temperature arc (which is generated by three graphite electrodes or copper electrodes of a three-phase arc furnace)
Data Source
AI summary
A manufacturing method of a large-outer-diameter quartz crucible for a Czochralski (CZ) single crystal is provided. The manufacturing method is a vacuum arc method, and specifically includes: releasing a high-temperature arc with an electrode bundle composed of 2N+1 electrodes to fuse a crucible blank, and performing rapid cooling to form an initial quartz crucible product, where N is an integer greater than or equal to 2; the 2N+1 electrodes include one central main electrode and 2N auxiliary electrodes; the 2N auxiliary electrodes are equidistantly distributed on a circumference with the central main electrode as a center; the central main electrode is aligned at an axis of the crucible mold; the 2N auxiliary electrodes are connected to two phases of an industrial three-phase power, and the two phases are alternately arranged on the auxiliary electrodes; the central main electrode is connected to a remaining phase of the industrial three-phase power.