Flat Induction Coil for Simultaneous Silicon Rod Production
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Solution Overview
Problem
Existing methods for producing thin silicon rods are limited in scalability and efficiency, as they typically produce one rod at a time, leading to high production costs, energy consumption, and material inefficiencies, particularly in the Siemens process for semiconductor and solar cell manufacturing.
Innovation Solution
A method utilizing a flat induction coil with multiple draw openings and a central opening, where multiple thin silicon rods are drawn simultaneously from a melt pool created by heating a raw silicon rod, allowing for uniform temperature profiles and dopant inclusion to enhance crystal growth and electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-coil induction coil is used to produce thin silicon rods, then one rod can be produced at a time, but productivity is low and production costs are high
Solution Approach 1:
The single induction coil is segmented into multiple independent coil sections (first induction coil, second induction coil, third induction coil) arranged around the raw rod. Each coil section independently heats a separate growth point, enabling simultaneous production of multiple thin silicon rods from different locations on the raw rod, thereby dramatically increasing productivity.
Solution Approach 2:
The induction coil system is designed to perform multiple functions: it simultaneously heats multiple growth points on the raw rod, supports multiple crystal growth processes occurring in parallel, and can produce multiple thin silicon rods of different specifications from a single raw rod, maximizing device utilization and productivity.
2Productivity
If high frequency current is applied to melt the raw rod, then crystal growth can proceed, but energy consumption increases
Solution Approach 1:
The heating process is segmented into multiple localized zones along the raw rod, with each coil section heating only its specific growth point. This distributed heating approach is more energy-efficient than melting the entire raw rod at once, as energy is concentrated only where needed for crystal growth.
Solution Approach 2:
The induction heating system operates continuously to maintain melt pools at multiple growth points simultaneously, eliminating the need to stop and restart heating between rod productions. This continuous operation optimizes energy utilization by keeping the system in an efficient steady state.
3Productivity
If a thin rod is drawn through the central opening with circumfluent current, then one rod production is achieved, but scalability is limited
Solution Approach 1:
The coil system is divided into multiple independent heating zones (first, second, and third induction coils) positioned at different locations around the raw rod. Each zone independently draws a thin silicon rod through its own growth point, enabling parallel production of multiple rods simultaneously without interfering with each other.
Solution Approach 2:
The system transitions from single-point heating (central opening) to multi-point heating distributed around the raw rod in a spatial arrangement. By utilizing the circumferential dimension around the rod, multiple growth points are created simultaneously, dramatically increasing productivity while maintaining manageable device complexity through modular coil design.
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 enables the simultaneous production of multiple thin silicon rods with improved material purity and reduced costs, increasing productivity and energy efficiency while maintaining uniform crystal growth and electrical properties.
Implementation Method 1
An upper end of a raw silicon rod is heated by induction using the flat induction coil so as to form a melt pool
Implementation Method 2
A respective thin silicon rod is drawn upwards through each of the plurality of draw openings in the flat induction coil from the melt pool
Data Source
AI summary
A method for producing thin silicon rods using a floating zone crystallization process includes supplying high frequency (HF) current to a flat induction coil having a central opening, a plurality of draw openings and a plate with a slot as a current supply of the HF current so as to provide a circumfluent current to the central opening. An upper end of a raw silicon rod is heated by induction using the flat induction coil so as to form a melt pool. A thin silicon rod is drawn upwards through each of the plurality of draw openings in the flat induction coil from the melt pool without drawing a thin silicon rod through the central opening having the circumfluent current.