Silicon Single Crystal Ingot Shouldering Process Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The Czochralski method for growing silicon single crystals faces challenges in reducing dislocation rates during the shouldering process, where the crystal diameter is rapidly increased, leading to suboptimal crystal quality.
Innovation Solution
A method that adjusts both the pulling speed and temperature conditions during the growth of the shoulder part of the silicon single crystal ingot, involving a first operation to decrease these parameters and a second operation to maintain them at lower values, allowing for controlled growth and reduced thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pulling speed is increased during the shouldering process to grow the crystal diameter rapidly, then the productivity is improved, but the dislocation occurrence rate increases and crystal quality deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting both the pulling speed and temperature conditions during the shouldering process. Specifically, the pulling speed is decreased from a first pulling speed to a second pulling speed, and the temperature conditions are adjusted by changing the temperature drop management value from a first management value to a second management value. This coordinated parameter adjustment allows the crystal to grow with controlled diameter increase while minimizing thermal stress and dislocation formation, thus resolving the contradiction between productivity and crystal quality.
2Manufacturing precision
If the pulling speed is decreased to reduce dislocations, then the crystal quality is improved, but the productivity decreases
Solution Approach 1:
The patent merges two control actions into a unified process: controlling pulling speed and controlling temperature conditions simultaneously. By combining these two parameters in a coordinated manner during the shouldering process, the system achieves both reduced dislocation rates (improved crystal quality) and maintained productivity. The merging of these control mechanisms allows the crystal to grow at optimized rates without sacrificing quality.
3Manufacturing precision
If the temperature conditions are adjusted to control crystal shape, then the dislocation rate is reduced, but the process complexity increases
Solution Approach 1:
The patent manages process complexity by implementing systematic parameter changes with defined relationships. The temperature drop management value is changed from a first management value to a second management value in coordination with pulling speed adjustments. This structured approach to parameter management, where temperature and speed changes are linked, simplifies the control process while effectively reducing dislocation rates through optimized thermal conditions during crystal growth.
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 silicon single crystal ingot with improved quality and a lower frequency of dislocations, as the controlled shape of the shoulder part minimizes thermal stress and optimizes crystal growth.
Implementation Method 1
polycrystalline silicon is inserted into a quartz crucible and is melted by heating a graphite heating element
Implementation Method 2
crystallization occurs on a molten solution interface and, thus, the seed crystal is rotated and pulled up, thereby growing a single crystal silicon ingot
Implementation Method 3
a pulling part to pull a single crystal grown from the molten silicon solution
Data Source
AI summary
An embodiment provides a method for manufacturing a silicon single crystal ingot by using a silicon single crystal growing apparatus comprising: a chamber; a crucible arranged inside the chamber and accommodating a molten silicon solution; a heater arranged outside the crucible so as to heat the crucible; a heat shielding part arranged inside the chamber; and a pulling part for pulling a single crystal growing from the molten silicon solution, wherein the method can comprise a step of respectively growing a neck part, a shoulder part and a body part.