Silicon (111) Ingot Diameter Control via Facet Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The growth of silicon single crystal ingots with (111) crystal orientation faces challenges in maintaining a consistent diameter due to facet formation, leading to errors in pulling speed control and reduced manufacturing yield.
Innovation Solution
A method and apparatus that measure the facet length of silicon single crystal ingots using an automatic diameter control sensor, calculating correction formulas for seed rotation speed and pulling speed to adjust and maintain the facet length within a preset range, thereby ensuring the ingot grows to a sufficient diameter for wafer manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the silicon single crystal ingot is grown with (111) crystal orientation, then the ingot can be formed, but facets are formed on the surface causing diameter variation and reducing manufacturing yield
Solution Approach 1:
The patent implements a feedback control mechanism where the automatic diameter control sensor continuously measures the ingot diameter, and when a facet is detected (indicated by diameter decrease), the system automatically adjusts the rotation speed or pulling speed to prevent the facet from entering the sensor's measurement range, thereby maintaining diameter consistency and improving manufacturing yield
Solution Approach 2:
The patent changes operational parameters (rotation speed or pulling speed) in response to detected facets. When a facet is detected causing diameter variation, the system adjusts these parameters to control facet behavior, thereby maintaining consistent effective diameter and improving manufacturing precision
2Measurement precision
If the automatic diameter control sensor measures the ingot diameter, then real-time diameter data is obtained, but measurement errors occur when facets enter the sensor's illumination range
Solution Approach 1:
The system uses feedback from the diameter measurement to detect facet entry (sudden diameter decrease) and triggers corrective action by adjusting rotation or pulling speed, ensuring the facet moves out of the sensor's measurement range, thereby maintaining both measurement precision and control reliability
Solution Approach 2:
The system takes preliminary action by detecting the approach of a facet (through diameter variation) and adjusts operational parameters before the facet fully enters the sensor range, preventing measurement errors and maintaining control reliability
3Manufacturing precision
If the pulling speed is adjusted by the automatic growth controller, then long-period diameter control is achieved, but short-period fluctuations occur due to ADC control operations
Solution Approach 1:
The patent separates the control functions into different time scales: the automatic growth controller handles long-period diameter control through pulling speed adjustment, while the facet detection and correction mechanism handles short-period fluctuations through rotation speed adjustment, thereby maintaining both diameter precision and pulling speed stability
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 effectively controls facet length, preventing diameter variations and enhancing the manufacturing yield of silicon single crystal ingots by adjusting seed rotation and pulling speeds based on real-time measurements, ensuring the ingot reaches the target diameter for wafer production.
Implementation Method 1
an automatic diameter control (ADC) sensor configured to measure a diameter of a silicon single crystal ingot having crystal orientation of (111)
Implementation Method 2
heating a growth furnace filled with high-purity silicon melt at a high temperature
Implementation Method 3
a water cooling tube fixed at an inner upper portion of the chamber and disposed around a silicon single crystal ingot grown to be pulled up from the crucible
Implementation Method 4
growing a silicon single crystal ingot having crystal orientation of (111) using the Czochralski method
Implementation Method 5
V/G, which is a ratio of a pulling speed (V) and a temperature gradient (G) at a solid-liquid interface
Data Source
AI summary
Embodiments provide a method of growing a silicon single crystal ingot, the method including growing a silicon single crystal ingot having crystal orientation of (111) using the Czochralski method, measuring a diameter of the silicon single crystal ingot, calculating a length of a facet of the silicon single crystal ingot, calculating a correction formula for a rotation speed of a seed and a correction formula for a pulling speed of the silicon single crystal ingot based on the calculated facet length, and correcting the rotation speed of the seed and the pulling speed of the silicon single crystal ingot based on a result of the calculation.