Semiconductor Fin Isolation and Gate Spacer Layout for Precise Patterning
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Solution Overview
Problem
The semiconductor industry faces challenges in manufacturing smaller and more complex integrated circuits due to limitations in patterning techniques, particularly in forming self-aligned isolation fins and gate structures, which affect the density and efficiency of semiconductor devices.
Innovation Solution
The method involves forming active fins on a substrate, depositing a spacing layer, and using self-aligned processes to create trenches and fill them with dielectric material to form isolation fins, followed by gate replacement and patterning to achieve precise and efficient semiconductor structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional patterning techniques are used, then manufacturing process is simpler, but manufacturing precision deteriorates
Solution Approach 1:
The patterning process is divided into multiple stages: forming mandrels at a first pitch, depositing spacers, selectively removing portions, and forming final structures at a second pitch. This segmentation enables achievement of finer patterning precision through sequential steps rather than attempting to create all features in a single patterning operation.
Solution Approach 2:
Mandrels are formed in advance as sacrificial structures that guide subsequent spacer formation. The spacers are deposited and patterned before final structure formation, allowing precise positioning to be established early in the process and maintained through subsequent steps.
2Quantity of substance
If geometry size is decreased, then functional density is improved, but manufacturing precision deteriorates
Solution Approach 1:
The invention transitions from two-dimensional planar patterning to three-dimensional vertical structures through spacer formation on mandrels. This dimensional transition enables higher functional density by utilizing vertical space while maintaining precise lateral geometry control through the self-aligned nature of spacer deposition.
Solution Approach 2:
The spacer structures are formed through self-aligned deposition processes where the spacer material automatically conforms to the mandrel sidewalls. This self-alignment mechanism inherently maintains precise geometry without requiring additional alignment steps, enabling accurate feature dimensions even at reduced geometry sizes.
3Manufacturing precision
If self-aligned processes are used, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
Multiple functions are merged into the spacer structures: they serve as alignment references, define final feature patterns, and become part of the functional device structure. This merging reduces the need for separate alignment and patterning steps, improving precision while managing complexity through multi-functionality.
Solution Approach 2:
The mandrels serve as intermediary sacrificial structures that facilitate precise spacer formation but are subsequently removed. These intermediaries enable the self-aligned patterning process to achieve high precision without permanently adding complex structures to the final device.
Data Source
AI summary
A semiconductor device includes an active fin disposed on a substrate, a gate structure, and a pair of gate spacers disposed on sidewalls of the gate structure, in which the gate structure and the gate spacers extend across a first portion of the active fin, and a bottom surface of the gate structure is higher than a bottom surface of the gate spacers.