Fin-Cut Semiconductor Structure for Source/Drain Protection

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Solution Overview

Problem

The semiconductor industry faces challenges in manufacturing FinFETs due to the risk of damaging source/drain features during the etching process for forming fin cutting structures, which affects device performance and increases manufacturing complexity.

Innovation Solution

A semiconductor structure is developed with a fin cutting structure where the portion extending into the active region is narrower than the portion extending into the isolation structure, reducing the risk of damage during etching and improving device performance by lowering sheet resistance, and relaxing the critical dimension and overlay window of the photolithography process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional etching process is used to form fin cutting structures, then the cutting structures can be formed, but the source/drain features are damaged

Engineering Contradiction:

Improvefin cutting structure formationVSAvoidsource/drain feature damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A mandrel structure is introduced as an intermediary element during the etching process. The mandrel serves as a protective template that defines the etching boundaries and prevents the etch from damaging the source/drain features. After the fin cutting structure is formed, the mandrel is removed, having served its protective function during fabrication.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The mandrel structure is formed in advance before the etching process. This preliminary structure preparation allows the subsequent etching to proceed with defined boundaries that protect the source/drain regions, preventing damage before it can occur during the cutting structure formation.

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If the fin cutting structure extends narrowly into the active region, then source/drain features are protected, but the manufacturing process becomes more complex

Engineering Contradiction:

Improvesource/drain feature protectionVSAvoidmanufacturing process complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The mandrel structure serves multiple functions simultaneously: it defines the etching boundaries to protect source/drain features, acts as a self-aligned template for the fin cutting structure formation, and eliminates the need for separate alignment steps. This self-service approach simplifies the overall manufacturing process despite the additional mandrel formation step.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20240258394A1Semiconductor structure and method for forming the same

Publication Date: 2024.08.01 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method for forming a semiconductor structure is provided. The method for forming the semiconductor structure includes forming an active region extending in a first horizontal direction, forming an isolation structure surrounding the active region, forming a gate dielectric layer over the active region and the isolation structure, forming a gate electrode layer nested within the gate dielectric layer, and removing the gate electrode layer and a first portion of the gate dielectric layer over the isolation structure to form a trench. A second portion of the gate dielectric layer over the active region is left to form first protection features. The method further includes depositing a dielectric layer in the trench.