Minimal Fin Layout Using SDB Trenches for Lithography Margin

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Solution Overview

Problem

Current FinFET fabrication methods face challenges with window limitation in the lithography process when integrating single diffusion break (SDB) structures and metal gate fabrication.

Innovation Solution

A method is developed to fabricate minimal fin length semiconductor devices by forming fin-shaped structures and using SDB structures to divide them into portions, followed by a fin-cut process to remove certain portions, thereby expanding the photolithography window.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional FinFET fabrication methods are used with SDB structures, then metal gate fabrication can be integrated, but window limitation in lithography process occurs

Engineering Contradiction:

Improveintegration of SDB structure and metal gate fabricationVSAvoidlithography window limitation

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The fin-shaped structure is divided into multiple portions by forming first and second SDB trenches that extend in a direction different from the fin orientation. This segmentation allows selective removal of specific fin portions while maintaining others, effectively expanding the lithography window and enabling precise control over gate formation areas.

Inventive Principle:

Principle #1Segmentation

2Length of moving object

If fin length is reduced to minimal length, then device scaling is improved, but lithography alignment and focus become more difficult

Engineering Contradiction:

Improvefin lengthVSAvoidlithography focus and alignment

Core Design Contradiction:

Length of moving objectVSManufacturing precision

Solution Approach 1:

SDB trenches are introduced as intermediary structures that extend perpendicular to the fin direction. These trenches act as physical guides and markers during lithography processes, providing reference features that improve alignment and focus even when the actual fin length between SDB structures is minimal. The SDB structures serve as mediating elements that decouple the lithography precision requirements from the minimal fin dimensions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12278265B2Method for fabricating a fin with minimal length between two single-diffusion break (SDB) trenches

Publication Date: 2025.04.15 UNITED MICROELECTRONICS CORP

AI summary

A method for fabricating minimal fin length includes the steps of first forming a fin-shaped structure extending along a first direction on a substrate, forming a first single-diffusion break (SDB) trench and a second SDB trench extending along a second direction to divide the fin-shaped structure into a first portion, a second portion, and a third portion, and then performing a fin-cut process to remove the first portion and the third portion.