Fin Structure Pitch Variation for Void Reduction in Multigate Transistors
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Solution Overview
Problem
Current semiconductor devices face challenges in maintaining uniform pitch and depth variations in fin structures, leading to performance degradation due to voids and reduced channel control, particularly with the quadruple patterning technique (QPT), which affects the reliability and operation of the devices.
Innovation Solution
The semiconductor device design incorporates fins and trenches with specific pitch and depth variations, alternating between smaller and larger variations to minimize void formation and enhance channel control, using a quadruple patterning technique with adjusted photo resist lengths and intervals to achieve uniformity and stability, and includes a fin-cut process to optimize fin layout and prevent performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If quadruple patterning technique (QPT) is used to form fins, then fin density is increased, but pitch uniformity deteriorates leading to voids and performance degradation
Solution Approach 1:
The patent divides the fin structure into alternating groups: some fins have uniform pitch (first pitch) while adjacent fins have non-uniform pitch (second pitch). This segmentation allows the structure to benefit from high density while managing void formation by creating intentional pitch variations in specific regions.
Solution Approach 2:
Different pitch characteristics are applied to different locations: fins in first trenches have uniform pitch for stable gate deposition, while fins in second trenches have non-uniform pitch to reduce void formation. This local differentiation resolves the contradiction between density and uniformity.
2Quantity of substance
If fin pitch is reduced to increase density, then device density is improved, but void formation increases leading to reliability degradation
Solution Approach 1:
The fin array is segmented into regions with different pitch characteristics. By alternating between uniform and non-uniform pitch regions, the structure achieves high overall density while specific non-uniform regions prevent void formation, maintaining reliability.
Solution Approach 2:
The patent intentionally introduces pitch non-uniformity (which might seem like a defect) to convert the harmful void formation effect into a beneficial feature. The non-uniform pitch regions specifically prevent voids, turning what could be a manufacturing defect into a reliability enhancement.
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes a substrate, a plurality of fins comprising a first fin, a second fin, a third fin, a fourth fin and a fifth fin, each of the plurality of protruding from the substrate in a first direction, and spaced apart from one another in a second direction that intersects the first direction and a plurality of trenches comprising a first trench, a second trench, a third trench and a fourth trench, each of the plurality of trenches being formed between adjacent fins of the plurality of fins, wherein variation of a first width of the first trench and a third width of the third trench is smaller than a first variation, wherein variation of a second width of the second trench and a fourth width of the fourth trench is smaller than a second variation, and wherein the second variation is greater than the first variation.