Nitridized Capping Layer Structure for Semiconductor Fin Oxidation Protection
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Solution Overview
Problem
Conventional liners or capping layers in semiconductor manufacturing, such as silicon nitride and siliconborocarbonitride, suffer from 'dishing' issues in shallow trench isolation (STI) structures, which affect the integrity and performance of semiconductor devices.
Innovation Solution
A method involving the formation of a nitridized capping layer and a nitridized oxide layer over semiconductor fins, followed by a dielectric layer, which are then selectively etched to mitigate 'dishing' by controlling nitrogen diffusion and maintaining a flat surface, thereby protecting the fins from oxidation during annealing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liners or capping layers (silicon nitride, siliconborocarbonitride) are used, then the fins are protected from oxidation, but dishing issues occur in shallow trench isolation structures
Solution Approach 1:
The capping layer is divided into multiple segments: a first capping layer (nitridized oxide) and a second capping layer (nitridized capping layer), each with different compositions and functions. This segmentation allows the first layer to provide oxidation protection while the second layer prevents nitrogen diffusion, thereby eliminating dishing issues while maintaining protection from oxidation
Solution Approach 2:
Different regions of the capping structure are given different properties: the first capping layer has oxidation-resistant properties, while the second capping layer has nitrogen-diffusion-blocking properties. This local differentiation of material properties allows each layer to perform its specific function optimally, resolving the contradiction between protection and dishing prevention
2Reliability
If nitrogen-containing capping layers are used to protect fins, then oxidation is prevented, but nitrogen diffuses into the dielectric layer causing dishing
Solution Approach 1:
The first capping layer (nitridized oxide) acts as an intermediary barrier between the nitrogen-containing second capping layer and the dielectric layer. This intermediary structure prevents nitrogen diffusion into the dielectric layer while allowing the second layer to maintain its oxidation protection function, thereby resolving the dishing issue caused by nitrogen diffusion
Solution Approach 2:
The nitrogen that would normally cause dishing harm is converted into a benefit by containing it within the second capping layer. The nitrogen provides enhanced oxidation protection while the first capping layer prevents its harmful diffusion, thus converting the potential harm into a beneficial protective feature
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 solution effectively resolves the 'dishing' issue, maintains the structural integrity of semiconductor fins, and prevents oxidation during annealing, enhancing device performance and reliability.
Implementation Method 1
mitigate 'dishing' by controlling nitrogen diffusion
Implementation Method 2
protecting the fins from oxidation during annealing processes
Data Source
AI summary
A semiconductor structure includes a substrate, a fin, a bottom capping structure and a top capping structure. The fin disposed on the substrate, the fin has a lower portion and an upper portion extending upwards from the lower portion. The bottom capping structure covers a sidewall of the lower portion of the fin. The top capping structure covers a sidewall of the upper portion of the fin.