Silicon Carbide Wafer Growth With Nitrogen Reduction for Alignment
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Solution Overview
Problem
Silicon carbide wafers have low visible light transmittance due to their dark brown color, leading to potential position deviations during semiconductor manufacturing, which results in insufficient process yield.
Innovation Solution
A manufacturing method involving a reactor with reduced nitrogen content, using argon gas to dilute residual nitrogen, and heating silicon carbide raw materials to form a silicon carbide ingot, which is then cut into wafers with improved visible light transmittance and resistivity, enabling accurate alignment and increased yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon carbide wafer is used for semiconductor manufacturing, then high temperature resistance and high stability are improved, but visible light transmittance deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the nitrogen content in the silicon carbide crystal during the growth process. By reducing the nitrogen content to 1×10^16 atoms/cm³ or less through specific gas flow rate control (argon gas at 1,000-5,000 sccm) and growth condition optimization, the visible light transmittance is improved to greater than 50% while maintaining the high temperature resistance and stability of silicon carbide material.
2Manufacturing precision
If alignment mark is set on silicon carbide wafer surface, then position deviation in manufacturing process is reduced, but position confirmation accuracy deteriorates due to low transparency
Solution Approach 1:
The patent resolves this contradiction by changing the optical parameter of the silicon carbide wafer through nitrogen content control. By reducing nitrogen content to 1×10^16 atoms/cm³ or less, the visible light transmittance increases to greater than 50%, making the alignment mark visible and detectable through the wafer, thereby enabling accurate position confirmation while maintaining manufacturing precision.
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 enhances visible light transmittance of silicon carbide wafers to greater than 50%, allowing for more accurate positioning and improved manufacturing yield in semiconductor processes.
Implementation Method 1
An argon gas is passed into the reactor, where a flow rate of passing the argon gas into the reactor is 1,000 sccm to 5,000 sccm, and a time of passing the argon gas into the reactor is 2 hours to 48 hours
Implementation Method 2
The reactor and the raw material are heated to form a silicon carbide material on the seed
Implementation Method 3
The reactor and the raw material are cooled to obtain a silicon carbide ingot
Data Source
AI summary
A manufacturing method of a silicon carbide wafer includes the following. A raw material containing carbon and silicon and a seed located above the raw material are provided in a reactor. A nitrogen content in the reactor is reduced, which includes the following. An argon gas is passed into the reactor, where a flow rate of passing the argon gas into the reactor is 1,000 sccm to 5,000 sccm, and a time of passing the argon gas into the reactor is 2 hours to 48 hours. The reactor and the raw material are heated to form a silicon carbide material on the seed. The reactor and the raw material are cooled to obtain a silicon carbide ingot. The silicon carbide ingot is cut to obtain a plurality of silicon carbide wafers. A semiconductor structure is also provided.