Nested Crucible Weir Circuitous Melt Flow

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Solution Overview

Problem

Existing systems for producing semiconductor or solar ingots by the Czochralski method face challenges in maintaining temperature stability and preventing dislocations and impurity concentrations, as well as enhancing heat transfer within the melt.

Innovation Solution

A system comprising an outer crucible, an inner crucible, and weirs that separate the melt into multiple zones, with the weirs supporting the inner crucible and facilitating heat transfer by creating a circuitous path for the melt, thereby maintaining temperature stability and reducing impurity concentrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a single crucible system is used, then the device complexity is low, but the temperature stability and heat transfer to the melt are insufficient

Engineering Contradiction:

Improvetemperature stabilityVSAvoidcrucible system complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The crucible system is divided into an outer crucible and an inner crucible, with the inner crucible suspended within the outer crucible. This segmentation allows independent thermal management of different melt zones, enabling stable temperature control in the inner crucible while maintaining overall system functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The inner crucible is nested within the outer crucible, creating a concentric configuration where the inner crucible is supported by weirs that extend from the outer crucible base. This nesting arrangement maximizes heat transfer surface area while maintaining compact device structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Temperature

If the melt is stagnant, then the temperature distribution is uniform, but the heat transfer to the melt is insufficient

Engineering Contradiction:

Improveheat transfer to meltVSAvoidmelt stability

Core Design Contradiction:

TemperatureVSStability of the object's composition

Solution Approach 1:

Weirs act as intermediary structures that direct melt flow patterns. The weirs create a circuitous flow path that forces the melt to move in a controlled manner, enhancing heat transfer from the crucible walls to the melt while preventing turbulent surface disruptions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The weirs are positioned to create curved, circuitous flow paths for the melt rather than straight-line flow. This curvature promotes gentle circulation that enhances convective heat transfer while maintaining surface stability suitable for crystal growth.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Temperature

If the melt flows directly from outer to inner crucible, then the heat transfer is efficient, but surface disruptions occur

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidsurface disruptions

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The weirs are strategically positioned to create curved, circuitous flow paths for the melt. This curved flow geometry enhances heat transfer efficiency by increasing the contact time and surface area between the melt and heated crucible walls, while simultaneously preventing direct, disruptive flow that would cause surface instabilities.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The system creates a dynamic, controlled circulation pattern where the melt flows circuitously between the outer and inner crucibles through the weir structures. This dynamic flow regime optimizes heat transfer while maintaining surface stability, as opposed to static or directly turbulent flow patterns.

Inventive Principle:

Principle #15Dynamics

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 system effectively limits temperature fluctuations and surface disruptions, enhances heat transfer, and reduces impurity concentrations, resulting in higher quality ingots with improved structural integrity and impurity characteristics.

Implementation Method 1

The weir is disposed between the outer crucible and the inner crucible for supporting the inner crucible. The opening is sized to facilitate the transfer of heat between the outer cavity and the inner cavity.

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

the temperature and the stability of the surface of the melt immediately adjacent to the ingot must be maintained substantially constant. Further, the melt temperature adjacent to the ingot must be maintained at a sufficiently high temperature to prevent the melt from prematurely solidifying.

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9822466B2Crystal growing systems and crucibles for enhancing heat transfer to a melt

Publication Date: 2017.11.21 CORNER STAR LTD

AI summary

A system for growing an ingot from a melt includes an outer crucible, an inner crucible, and a weir. The outer crucible includes a first sidewall and a first base. The first sidewall and the first base define an outer cavity for containing the melt. The inner crucible is located within the outer cavity, and has a central longitudinal axis. The inner crucible includes a second sidewall and a second base having an opening therein. The opening in the second base is concentric with the central longitudinal axis. The weir is disposed between the outer crucible and the inner crucible for supporting the inner crucible.