Semiconductor Wafer Edge Nitrogen Oxygen Gradient
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Solution Overview
Problem
Semiconductor wafer processing at high temperatures generates thermal gradients, leading to mechanical stress and crystal defects such as slip lines, which can impair the performance of electrical devices, especially as wafer size increases, making it challenging to maintain mechanical stability during front-end-of-line (FEOL) processing.
Innovation Solution
A semiconductor wafer with varying concentrations of nitrogen and oxygen, where the average concentration in the edge part exceeds that in the central part by more than 20%, is created by introducing these elements through the side surface, forming a diffusion barrier on the main surfaces to enhance mechanical stability and prevent slip line formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high temperature processing is applied to semiconductor wafers, then material deposition and modification can be achieved, but thermal gradients generate mechanical stress leading to crystal defects such as slip lines
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of nitrogen and oxygen concentrations within the semiconductor wafer. Specifically, the edge region (first part) is enriched with nitrogen and oxygen at concentrations exceeding 5×10^14 cm^-3, while the central region (second part) maintains lower concentrations. This localized compositional variation provides differential mechanical properties that compensate for thermal stress gradients during high-temperature processing, preventing slip line formation at critical edge regions without compromising the electrical properties of the central device regions.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the concentrations of nitrogen and oxygen throughout the wafer structure. The nitrogen concentration in the edge region is controlled to exceed 5×10^14 cm^-3, creating a compositional parameter gradient that directly influences the mechanical stress response. This parameter modification allows the wafer to maintain crystal structure integrity during thermal processing by adjusting the local mechanical properties through controlled impurity distribution.
2Productivity
If wafer size is increased to improve productivity, then more devices can be manufactured, but mechanical stability during processing becomes more challenging to maintain
Solution Approach 1:
The patent addresses the mechanical stability challenge in large wafers by applying local quality enhancement at the edge regions. By concentrating nitrogen and oxygen enrichment (exceeding 5×10^14 cm^-3) specifically in the first part extending from the side surface to a second part, the patent creates localized mechanical reinforcement zones. This localized strengthening compensates for the increased thermal stress and mechanical loads experienced by larger wafer dimensions during processing, enabling maintained mechanical stability despite increased wafer size for higher productivity.
3Strength
If nitrogen and oxygen are introduced into the semiconductor block through the side surface, then mechanical stability is improved, but a non-uniform concentration distribution is created
Solution Approach 1:
The patent deliberately employs local quality by creating a controlled non-uniform concentration distribution of nitrogen and oxygen. The edge region (first part) is specifically enriched with concentrations exceeding 5×10^14 cm^-3, while the central region (second part) maintains lower concentrations. This intentional compositional non-uniformity provides the mechanical reinforcement needed at stress-prone edge regions without introducing harmful effects into the central device regions, thus resolving the contradiction between mechanical stability improvement and compositional uniformity.
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 improves mechanical stability by strengthening the edge area of the wafer, reducing undesirable defect generation and maintaining performance by controlling slip line formation and thermal donor formation, thus enhancing the reliability of semiconductor devices.
Implementation Method 1
introducing at least one of nitrogen and oxygen into the semiconductor block through the side surface
Implementation Method 2
A diffusion barrier is formed on at least one of opposite first and second main surfaces of the semiconductor wafer
Data Source
AI summary
A semiconductor wafer includes first and second main surfaces opposite to each other along a vertical direction, and a side surface encircling the semiconductor wafer. A lateral distance perpendicular to the vertical direction between the side surface and a center of the semiconductor wafer includes first and second parts. The first part extends from the side surface to the second part and the second part extends from the first part to the center. An average concentration of at least one of nitrogen and oxygen in the first part is greater than 5×1014 cm−3 and exceeds an average concentration of the at least one of nitrogen and oxygen in the second part by more than 20% of the average concentration of the at least one of nitrogen and oxygen in the second part.