Quartz Particle Arrays for Low-Defect Silicon Ingot Growth
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Solution Overview
Problem
Continuous Czochralski methods face challenges in reducing defect counts, particularly voids, in silicon wafers due to inert gas bubbles formed during the addition of solid polycrystalline silicon to the melt.
Innovation Solution
Incorporating an array of quartz particles connected by linking members into the crucible assembly before ingot growth, which provides nucleation points for inert gas bubbles to aggregate and increase their buoyancy, thereby enhancing their removal from the melt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If solid polycrystalline silicon is added to the melt to replenish the melt during ingot growth, then the melt is replenished and multiple ingots can be grown, but inert gas bubbles form in the melt which increases the void count in wafers
Solution Approach 1:
Quartz particles are introduced as intermediary substances that provide surfaces for inert gas bubbles to attach to. These particles act as mediators between the bubbles and the melt, enabling bubbles to coalesce and rise more effectively to the surface for removal, thereby reducing void count while maintaining continuous feed operations
Solution Approach 2:
The invention converts the harmful effect of inert gas bubbles (which cause voids) into a beneficial process by providing quartz particles that facilitate bubble coalescence and removal. The bubbles that would otherwise be trapped and cause defects are now channeled to attach to particles and be efficiently removed at the melt surface
2Object-generated harmful factors
If quartz particles are added to provide nucleation points for bubble aggregation, then bubble removal is enhanced, but the device complexity increases
Solution Approach 1:
Rather than changing the fundamental structure of the crucible assembly, the invention changes the chemical/physical parameters by introducing quartz particles with specific properties (surface area, composition) that facilitate bubble attachment. This parameter-based approach achieves bubble removal without structural complexity
Solution Approach 2:
The quartz particles are simple, inexpensive additions to the melt system. They perform their function of providing nucleation sites and can be consumed or removed along with the melt,无需 complex recovery or maintenance 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 effectively reduces inert gas bubbles, leading to lower defect counts in silicon wafers by increasing the surface area for bubble aggregation and dissolution of quartz, thus improving the quality of single crystal silicon ingots.
Implementation Method 1
provides nucleation points for inert gas bubbles to aggregate and increase their buoyancy
Implementation Method 2
provides nucleation points for inert gas bubbles to aggregate and increase their buoyancy
Implementation Method 3
The polycrystalline silicon is heated to form a silicon melt
Implementation Method 4
The silicon melt is contacted with a seed crystal. The seed crystal is withdrawn from the silicon melt to form a silicon ingot
Data Source
AI summary
Methods for producing single crystal silicon ingots in which an array of quartz particles are added to the crucible assembly before ingot growth are disclosed. The array may be disposed in the outer melt zone of the crucible assembly as in a continuous Czochralski (CCz) process. The array may be made of quartz particles that are interconnected by linking members.