TiN Seed-Layer Deposition for Smooth Conformal Films

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Solution Overview

Problem

Existing methods for forming titanium nitride (TiN) films in integrated circuits face challenges in achieving conformality, electrical, and physical properties that are superior to those achieved by physical vapor deposition (PVD) and chemical vapor deposition (CVD), particularly in high aspect ratio structures, and often result in undesirable film morphologies due to initial growth modes on non-metal surfaces.

Innovation Solution

A method involving the use of a silicon (Si) and nitrogen (N) seed layer formed by atomic layer deposition (ALD) followed by a TiN layer, which promotes a layer-by-layer growth mode, resulting in a TiN film with improved conformality, reduced surface roughness, and lower electrical resistivity compared to TiN films formed without a seed layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If atomic layer deposition (ALD) is used to form TiN films, then conformality is improved, but electrical properties (conductivity) and physical properties (surface roughness) deteriorate

Engineering Contradiction:

ImproveconformalityVSAvoidelectrical properties and surface roughness

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A seed layer comprising silicon (Si) and nitrogen (N) is introduced as an intermediary between the substrate and the TiN layer. This seed layer promotes a layer-by-layer growth mode that improves the surface roughness and electrical properties of the TiN film while maintaining the conformality provided by ALD deposition

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The seed layer is formed in advance before depositing the TiN layer. This preliminary action prepares the surface to promote favorable growth modes for the subsequent TiN deposition, ensuring improved surface roughness and electrical properties from the outset

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If TiN is deposited in smaller trenches or vias to meet scaling requirements, then conformality requirement increases, but existing PVD and CVD methods become limited

Engineering Contradiction:

Improveconformality in high aspect ratio structuresVSAvoidsuitability for small dimension features

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The invention changes the deposition parameters by using thermal ALD or plasma-enhanced ALD with a seed layer, enabling conformal deposition in high aspect ratio structures with small dimensions while maintaining film quality

Inventive Principle:

Principle #35Parameter changes

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 method produces a TiN film with surface roughness and electrical resistivity comparable to or better than PVD and CVD methods, while maintaining conformality, suitable for high aspect ratio structures in integrated circuits.

Implementation Method 1

forming on the non-metallic surface a seed layer comprising silicon (Si) and nitrogen (N) by atomic layer deposition (ALD)

Methodology Applied

Scientific EffectAtomic layer deposition: Chemical Vapour Deposition

Implementation Method 2

forming on the seed layer a TiN layer by thermal ALD

Methodology Applied

Scientific EffectThermal atomic layer deposition: Chemical Vapour Deposition

Data Source

PatentUS12444603B2Smooth titanium nitride layers and methods of forming the same

Publication Date: 2025.10.14 EUGENUS INC

AI summary

The disclosed technology generally relates to forming a titanium nitride layer, and more particularly to forming by atomic layer deposition a titanium nitride layer on a seed layer. In one aspect, a semiconductor structure comprises a semiconductor substrate comprising a non-metallic surface. The semiconductor structure additionally comprises a seed layer comprising silicon (Si) and nitrogen (N) conformally coating the non-metallic surface and a TiN layer conformally coating the seed layer. Aspects are also directed to methods of forming the semiconductor structures.