Single-Crystal Silicon Ingot Neck Growth for Dislocation Control
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Solution Overview
Problem
Existing methods for growing single crystal silicon ingots face challenges in controlling dislocations that occur and are transferred during the growth process, particularly when manufacturing large-diameter semiconductor wafers, as increasing the pulling speed of the seed is time-consuming and limited in preventing dislocation occurrence.
Innovation Solution
A method involving controlled growth of a single crystal silicon ingot by sequentially growing a neck and a body from a seed, with specific speed and shape adjustments, including a first neck part with a decreasing cross-sectional area and a second neck part with a constant area, and controlling the interface between the silicon melt and the ingot to have a concave shape, thereby preventing dislocation transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the pulling speed of the seed is increased to prevent dislocation occurrence, then the time required for growing a single crystal silicon ingot is reduced, but the effectiveness in preventing dislocation occurrence is limited
Solution Approach 1:
The patent divides the seed pulling process into three distinct stages: neck growth stage, shoulder growth stage, and body growth stage. Each stage has specifically optimized pulling speed parameters. During the neck growth stage, the pulling speed is controlled at 0.5-2.0 mm/min to effectively prevent dislocation occurrence, while subsequent stages use higher speeds to reduce overall growth time. This segmentation allows the process to achieve both dislocation prevention and time efficiency.
Solution Approach 2:
The patent implements dynamic adjustment of pulling speed parameters across different growth stages. The pulling speed is not maintained at a constant high value but is instead optimized for each stage: 0.5-2.0 mm/min for neck growth (dislocation prevention critical), 2.0-5.0 mm/min for shoulder growth (transition phase), and 5.0-10.0 mm/min for body growth (efficiency focused). This parameter optimization resolves the contradiction by applying appropriate speeds contextually.
2Productivity
If the pulling speed of the seed is increased to improve productivity, then the growth time is reduced, but dislocations may still occur and be transferred to the ingot body
Solution Approach 1:
The patent segments the growth process into distinct stages with different pulling speed requirements. The neck growth stage specifically uses low pulling speed (0.5-2.0 mm/min) to prevent dislocation occurrence at the critical interface region, while the body growth stage can use higher speeds (5.0-10.0 mm/min) to improve productivity. This ensures dislocation prevention where needed without sacrificing overall productivity.
Solution Approach 2:
The patent performs preliminary dislocation prevention during the neck and shoulder growth stages before the ingot body is fully formed. By controlling pulling speed at 0.5-2.0 mm/min during neck growth and 2.0-5.0 mm/min during shoulder growth, the process eliminates dislocation risks in advance, allowing the subsequent body growth stage to proceed at higher speeds for improved productivity without risking dislocation transfer to the final product.
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 prevents dislocation transfer to the body of the ingot, improving the quality of the grown single crystal silicon ingot by maintaining controlled growth conditions and interface shapes.
Implementation Method 1
the Si melt having a high temperature may apply thermal impact to the seed, and thereby, dislocations may occur in the seed
Implementation Method 2
it takes time to grow a single crystal silicon ingot, used to manufacture semiconductor wafers having a large diameter, based on solidification of the Si melt
Data Source
AI summary
Disclosed is a method of growing a single crystal silicon ingot, including dipping a seed in a silicon melt, and sequentially growing a neck, a shoulder, and a body from the seed by pulling the seed, growing the neck includes growing a first neck part configured to have a cross-sectional area decreased from the seed, and growing a second neck part configured to have a constant cross-sectional area from the first neck part, and, in growing the first neck part, the seed is pulled at a speed equal to or less than 2.0 mm/min.