FinFET Isolation Structure With Insulating Cushioning Layer
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Solution Overview
Problem
In FinFET manufacturing, manufacturing deviations can cause the dummy gate structure to shift and form bridges with the fin, leading to electrical leakage and reduced carrier mobility due to misalignment and improper stress distribution in the channel.
Innovation Solution
A method involving a substrate structure with isolation regions of different heights, where the upper surface of the first isolation region aligns with the fin surface, and a series of etching processes to form insulating layers with varying selectivity ratios, ensuring the dummy gate structure does not bridge with the fin even if it deviates in position, thus maintaining stress distribution and carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the STI region is made lower than the fin to form a dummy gate structure, then device performance can be improved through stress control, but manufacturing deviations can cause the dummy gate to shift and form bridges with the fin, leading to electrical leakage
Solution Approach 1:
The patent applies beforehand cushioning by forming an insulating layer on the isolation region before forming the dummy gate structure. This insulating layer acts as a protective barrier that prevents electrical leakage even if the dummy gate shifts during manufacturing. The cushioning measure is implemented in advance to compensate for potential alignment deviations, ensuring that manufacturing imprecision does not lead to bridge formation and electrical leakage.
2Manufacturing precision
If the dummy gate structure is formed on the STI region to control critical dimension uniformity, then CD uniformity is improved, but the dummy gate may inadvertently contact the fin due to position shift, causing electrical leakage
Solution Approach 1:
The patent introduces an insulating layer as an intermediary between the isolation region and the dummy gate structure. This intermediary layer serves as a protective barrier that prevents direct contact between the dummy gate and the fin, thereby eliminating the harmful effect of electrical leakage even when the dummy gate position shifts during manufacturing processes.
3Manufacturing precision
If the dummy gate structure shifts position due to manufacturing deviation, then alignment precision deteriorates, but this can be compensated by forming an insulating layer on the isolation region
Solution Approach 1:
The patent applies beforehand cushioning by forming an insulating layer on the isolation region before forming the dummy gate structure. This insulating layer acts as a protective barrier that prevents electrical leakage even if the dummy gate shifts during manufacturing. The cushioning measure is implemented in advance to compensate for potential alignment deviations, ensuring that manufacturing imprecision does not lead to bridge formation and electrical leakage.
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 enhances device reliability and carrier mobility by preventing electrical leakage and maintaining desired stress distribution in the channel, even with manufacturing imprecision.
Implementation Method 1
performing a first etching process using the patterned barrier layer as a mask to remove an exposed portion of the third insulating layer and to expose a portion of the second insulating layer thereunder
Data Source
AI summary
The present disclosure relates to the technical field of semiconductor processes, and discloses a semiconductor device and a manufacturing method therefor. The semiconductor device includes a substrate; two fins located on the substrate and extending along a first direction; an isolation material layer surrounding the fins, comprising a first isolation regions located at an end region between the two fins along the first direction, and a second isolation region located at sides of the fins along a second direction that is different from the first direction, wherein an upper surface of the first isolation region substantially align with an upper surfaces of the fins, and an upper surface of the second isolation region is lower than the upper surface of the fins; and a first insulating layer on the first isolation region.