Polycrystalline Silicon Seed Rod Electrode Design

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Solution Overview

Problem

The existing polycrystalline silicon manufacturing apparatus faces challenges in increasing seed rod density due to reduced rigidity and deteriorated maintenance workability caused by the need for more perforation holes and cables as the number of electrodes increases, leading to decreased productivity and workability.

Innovation Solution

The apparatus employs two-holding electrodes that hold two silicon seed rods each, reducing the number of electrodes and perforation holes in the bottom plate, and uses a connecting member to link seed assemblies in series, eliminating the need for power source cables between them, thereby maintaining rigidity and improving maintenance access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If more electrodes are installed to hold more silicon seed rods, then the density of silicon seed rods increases and productivity improves, but the number of perforation holes in the bottom plate increases causing reduced rigidity and deformation

Engineering Contradiction:
Improvedensity of silicon seed rodsVSAvoidrigidity of bottom plate
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent combines multiple seed rod holding functions into a single electrode structure. The fork-shaped electrode holds two silicon seed rods simultaneously, reducing the total number of electrodes and perforation holes needed in the bottom plate, thereby maintaining bottom plate rigidity while increasing seed rod density

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from a single vertical holding position to a bifurcated fork-shaped structure that extends in multiple directions. This dimensional change allows one electrode to occupy spatial volume that would otherwise require multiple separate electrodes, enabling two seed rods to be held per electrode

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If more electrodes are installed to hold more silicon seed rods, then the density of silicon seed rods increases and productivity improves, but the number of cables and pipes increases causing deteriorated maintenance workability

Engineering Contradiction:
Improvedensity of silicon seed rodsVSAvoidmaintenance workability
Core Design Contradiction:
ProductivityVSEase of repair

Solution Approach 1:

The patent merges multiple electrode-cable-pipe assemblies into fewer combined units. By using fork-shaped electrodes that hold two seed rods each, the number of cables and cooling pipes required below the reaction furnace is reduced, improving maintenance accessibility and workability

Inventive Principle:
Principle #5Merging (Combining)

3Quantity of substance

If more perforation holes are formed in the bottom plate to install more electrodes, then more silicon seed rods can be held, but the bottom plate structure becomes weaker and more prone to deformation

Engineering Contradiction:
Improvenumber of silicon seed rodsVSAvoidstructural integrity of bottom plate
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent reduces the total number of perforation holes by combining multiple holding functions into single fork-shaped electrodes. This merging approach maintains the quantity of held seed rods while preserving bottom plate structural integrity by minimizing openings in the bottom plate

Inventive Principle:
Principle #5Merging (Combining)

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 allows for a higher density of silicon seed rods without compromising the bottom plate's rigidity, enhancing productivity and maintenance workability by reducing the number of perforation holes and cables, thus improving the efficiency of polycrystalline silicon production.

Implementation Method 1

a cooling passageway is formed in the inside of the electrode holder so as to flow a cooling medium

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a current is supplied from the electrode to the silicon seed rod so as to heat the silicon seed rod by means of a resistance thereof

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

raw gas composed of a mixed gas of chlorosilane and hydrogen is supplied to the reaction furnace to contact with the heated silicon seed rods, and then deposit polycrystalline silicon on surfaces thereof by means of hydrogen reduction and thermal decomposing of the raw gas

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Data Source

PatentEP2105408B1Polycrystalline silicon manufacturing apparatus
Publication Date: 2010.12.01 MITSUBISHI MATERIALS CORP
  • EP2105408B1 patent drawingFigure 1
  • EP2105408B1 patent drawingFigure 2
  • EP2105408B1 patent drawingFigure 3

AI summary

A polycrystalline silicon manufacturing apparatus is provided which supplies raw gas to the inside of a reaction furnace and supplies a current from an electrode to a silicon seed rod in a state where the vertically extending silicon seed rod is uprightly stood on each of the plural electrodes disposed in a bottom plate portion of the reaction furnace so as to heat the silicon seed rod and thus to deposit polycrystalline silicon on a surface of the silicon seed rod by means of the reaction of the raw gas.