Multilayer Inner Spacer Structure for GAA Source-Drain Protection

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Solution Overview

Problem

The structural damage to the inner spacer in nano-sheet transistors during the fabrication process can lead to damage of the source-drain region, causing IC failure and compromising the electrical insulation between the source-drain region and the gate structure.

Innovation Solution

A multilayered inner spacer structure is introduced, comprising a first dielectric layer formed before the source-drain region is created, and a second dielectric layer formed afterwards to protect the source-drain region from structural damage during subsequent fabrication processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single-layer inner spacer structure is used, then the fabrication process is simpler, but the source-drain region suffers structural damage during subsequent processing

Engineering Contradiction:

Improvefabrication process simplicityVSAvoidsource-drain region integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The inner spacer is divided into multiple layers (first inner spacer layer and second inner spacer layer) with different materials and functions. The first layer provides initial spacing and insulation, while the second layer provides enhanced protection during fabrication processes, thereby preventing source-drain region damage without significantly complicating the overall manufacturing流程

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first inner spacer layer is formed before the source-drain region, establishing a protective barrier in advance. This preliminary structure prevents structural damage to the source-drain region during subsequent fabrication processes such as etching and deposition

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the inner spacer is formed closer to the source-drain region, then electrical insulation is improved, but the risk of structural damage to the source-drain region increases

Engineering Contradiction:

Improveelectrical insulation between source-drain and gateVSAvoidstructural damage risk to source-drain

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The inner spacer is segmented into two layers positioned at different locations: the first layer is adjacent to the gate structure providing electrical insulation, while the second layer extends toward the source-drain region providing mechanical protection. This segmentation allows the structure to simultaneously achieve both electrical insulation and damage prevention

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second inner spacer layer acts as an intermediary protective barrier between the fabrication process and the source-drain region. It absorbs mechanical stress and protects the source-drain region from damage during etching and deposition processes while allowing the first layer to maintain electrical insulation

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12324209B2Spacer structure for semiconductor device

Publication Date: 2025.06.03 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

The present disclosure describes a semiconductor structure and a method for forming the same. The semiconductor structure can include a substrate, a fin structure over the substrate, a gate structure over the fin structure, a first inner spacer layer formed in the fin structure and adjacent to the gate structure, and a second inner spacer layer extending through the first inner spacer layer.