Cu Interconnect Capping Layer to Suppress Surface Scattering

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Solution Overview

Problem

The increasing device density in semiconductor devices and ICs leads to challenges in resistance performance of interconnect and redistribution layers due to surface scattering effects, which are not effectively addressed by existing technologies.

Innovation Solution

A capping layer made of a two-dimensional material is applied over the metallization pattern in semiconductor structures to suppress surface scattering, reducing resistivity and potentially eliminating the need for barrier and liner layers, thereby enhancing electrical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If device density is increased to achieve higher integration, then more devices and components can be integrated into a given volume, but resistance performance of interconnect and redistribution layers deteriorates due to surface scattering effects

Engineering Contradiction:

Improveintegration densityVSAvoidresistance performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A capping layer made of two-dimensional material (such as graphene, h-BN, or MoS2) is introduced as an intermediary between the Cu metallization pattern and the surrounding environment. This capping layer acts as a mediator that suppresses surface scattering of electrons, thereby reducing resistivity and improving electrical performance without interfering with the high integration density goal

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical and chemical parameters of the metallization pattern surface by applying a two-dimensional material capping layer. This alters the surface properties to reduce electron scattering, effectively changing the electrical resistance parameter from a deteriorating trend to an improved state while maintaining high device density

Inventive Principle:

Principle #35Parameter changes

2Reliability

If barrier and liner layers are used to protect metallization patterns, then reliability is improved, but device complexity and manufacturing complexity increase

Engineering Contradiction:

Improvemetallization pattern protectionVSAvoidlayer structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The capping layer made of two-dimensional material combines multiple functions into a single layer: it provides surface scattering suppression, acts as a diffusion barrier, and serves as a protective layer. This merging of functions eliminates the need for separate barrier and liner layers, reducing structural complexity from multiple layers to a single functional layer

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The two-dimensional material capping layer is designed to perform multiple functions simultaneously: electrical performance enhancement through surface scattering suppression, chemical protection through diffusion barrier properties, and physical protection through surface coverage. This multi-functionality replaces what traditionally required multiple specialized layers

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If Cu metallization pattern volume is increased to reduce resistivity, then electrical performance improves, but surface scattering effects become more significant

Engineering Contradiction:

Improveelectrical performanceVSAvoidsurface scattering effects

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful surface scattering effect into a beneficial outcome by applying a two-dimensional material capping layer. The capping layer transforms the high-surface-area Cu metallization pattern from a source of electron scattering into a structure where the two-dimensional material surface provides a smooth, low-scattering interface, thereby reducing resistivity despite the increased Cu volume

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The capping layer significantly reduces resistivity and improves the electrical performance of semiconductor structures by suppressing surface scattering, allowing for increased Cu metallization pattern volume and potentially omitting barrier and liner layers.

Implementation Method 1

surface scattering effects

Methodology Applied

Scientific EffectSurface scattering: Scattering

Data Source

PatentUS20250273572A1Semiconductor structure and manufacturing methods thereof

Publication Date: 2025.08.28 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor structure includes a substrate and an interconnect. The substrate has a semiconductor device. The interconnect is disposed over the substrate and electrically coupled to the semiconductor device, and includes a metallization layer and a capping layer. The metallization layer is disposed over the substrate and includes a via portion and a line portion connecting to the via portion. The capping layer covers the line portion, where the line portion is sandwiched between the via portion and the capping layer, and the capping layer includes a plurality of sub-layers.