Silicon Core Wire Threaded Rod Connection

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Solution Overview

Problem

Existing methods for unifying thin silicon rods in the Siemens process for producing polycrystalline silicon face issues with contamination and instability, particularly during welding and adapter-based assembly, which can lead to rod collapse and abnormal growth during the deposition process.

Innovation Solution

The solution involves forming male and female thread parts on the ends of thin silicon rods, which are screwed together for unification, optionally using an adapter with thread parts, to create a stable and contamination-free long silicon core wire, with the adapter being a silicon member to minimize risks of contamination and collapse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thin silicon rods are unified by welding, then the connection strength is improved, but contamination occurs during the welding process

Engineering Contradiction:

Improveconnection strengthVSAvoidcontamination

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a silicon-based adapter as an intermediary component between thin silicon rods. The adapter has a through-hole that receives and fixes the silicon rods, eliminating direct welding contact. This mediator approach allows mechanical connection without the contamination risks associated with welding processes, while maintaining connection strength through precise fitting and fixing mechanisms.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If thin silicon rods are pushed into adapter holes for unification, then assembly is simplified, but chipping or collapse occurs due to hard pushing

Engineering Contradiction:

Improveassembly simplicityVSAvoidrod stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the geometric parameters of the adapter's through-hole and the silicon rod ends to enable gentle insertion. The hole diameter is precisely controlled to be slightly larger than the rod diameter, allowing smooth insertion without forceful pushing. Additionally, the rod ends may be processed with specific surface characteristics that facilitate easy insertion while ensuring secure fixation, thereby preventing chipping and collapse during assembly.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If different materials are used for adapters and silicon rods, then assembly flexibility is improved, but contamination risk increases during deposition

Engineering Contradiction:

Improveassembly flexibilityVSAvoidcontamination

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent specifies that the adapter be made of silicon or silicon-based material, matching the material composition of the thin silicon rods. This homogeneity ensures that no foreign material contamination occurs during the deposition process. The silicon-based adapter maintains chemical compatibility with the silicon rods, preventing contamination while still providing the necessary mechanical functions of connection and fixation.

Inventive Principle:

Principle #33Homogeneity

4Productivity

If the silicon core wire is made longer to produce longer monocrystalline silicon, then productivity is improved, but the risk of collapse and abnormal growth increases

Engineering Contradiction:

Improvemonocrystalline silicon production efficiencyVSAvoidcore wire stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent divides the long silicon core wire into multiple segments (thin silicon rods) that are connected through silicon-based adapters. Each rod segment maintains structural integrity independently, and the adapters provide reliable connection points. This segmentation approach allows the core wire to achieve the necessary length for high productivity while maintaining stability throughout its length, preventing collapse and abnormal growth during the deposition process.

Inventive Principle:

Principle #1Segmentation

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 approach results in a simple, cost-effective, and stable long silicon core wire with reduced risks of contamination and collapse, enabling stable energization and efficient polycrystalline silicon deposition without abnormal growth or damage, as demonstrated by successful experiments achieving polycrystalline silicon rods up to 130 mm in diameter.

Implementation Method 1

the silicon core wire is heated to a deposition temperature by energization

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

polycrystalline silicon is vapor-deposited on a surface of the silicon core wire by a CVD reaction

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentUS11565939B2Silicon core wire

Publication Date: 2023.01.31 SHIN ETSU CHEMICAL CO LTD

AI summary

In the silicon core wire according to a first aspect of the present invention, a male thread part formed at one end of a first thin silicon rod and a female thread part formed at one end of a second thin silicon rod may be screwed together and fastened. In the silicon core wire according to a second aspect of the present invention, a thread part formed at one end of a first thin silicon rod and a thread part formed at one end of a second thin silicon rod may be screwed together and fastened via an adapter with thread parts formed at both ends.