Tungsten Digit Line Protection Using Titanium Nitride Liners

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Solution Overview

Problem

Tungsten-containing structures in integrated circuits, such as digit lines, are prone to degradation due to adjacent materials, which affects their conductive properties and integration levels, necessitating new methods to protect tungsten from degradation.

Innovation Solution

The use of titanium-nitride-containing materials as liners directly against tungsten-containing surfaces to prevent degradation, with titanium nitride formed through methods like metal-organic chemical vapor deposition (Mo-CVD) or atomic layer deposition, creating a protective layer between tungsten and other materials that might react with it.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If tungsten-containing structures are used in integrated circuits to achieve high integration levels, then productivity and integration density are improved, but the structures become prone to degradation from adjacent materials that affects conductive properties

Engineering Contradiction:

Improveintegration levelVSAvoidconductive property stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A protective material layer is introduced as an intermediary between the tungsten-containing structures and adjacent materials. This protective layer prevents direct contact and chemical reactions between tungsten and degrading materials, thereby maintaining the conductive properties of tungsten while enabling higher integration levels.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes chemical vapor deposition (CVD) processes to form the protective material layer. This involves introducing precursor gases that react on the tungsten surface to deposit a protective coating, using gas-phase chemistry to achieve uniform coverage at the nanoscale.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Productivity

If tungsten layer thickness is reduced to achieve higher integration density, then productivity is improved, but the tungsten becomes more susceptible to degradation from adjacent materials

Engineering Contradiction:

Improveintegration densityVSAvoidmaterial degradation susceptibility

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The protective material serves as a mediator that shields thin tungsten layers from harmful interactions with adjacent materials. This allows the tungsten layers to be made thinner for higher integration density while the protective layer prevents degradation that would otherwise occur more readily in thinner structures.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The structure becomes a composite system combining tungsten (for conductivity) with a protective material layer (for chemical stability). This composite approach leverages the strengths of each material while compensating for their weaknesses, enabling thin tungsten layers to maintain their conductive properties.

Inventive Principle:

Principle #40Composite materials

3Reliability

If protective material is added to prevent tungsten degradation, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveprotection from degradationVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protective material is applied as a thin film that conformally coats the tungsten-containing structures. This thin-film approach provides comprehensive protection while adding minimal structural complexity and maintaining compatibility with existing integrated circuit geometries.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The protective material layer serves multiple functions: it prevents chemical degradation from adjacent materials, acts as a diffusion barrier, and can serve as an etch stop layer. This multi-functionality reduces the need for additional separate protective structures, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This approach effectively protects tungsten surfaces from degradation, maintaining suitable conductive properties even in thinner layers, enabling higher integration levels and improved performance in memory arrays and integrated circuits.

Implementation Method 1

titanium nitride formed through methods like metal-organic chemical vapor deposition (Mo-CVD)

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Implementation Method 2

titanium nitride formed through methods like metal-organic chemical vapor deposition (Mo-CVD) or atomic layer deposition

Methodology Applied

Scientific EffectAtomic layer deposition:

Data Source

PatentUS11923305B2Methods of forming apparatuses having tungsten-containing structures

Publication Date: 2024.03.05 MICRON TECHNOLOGY INC

AI summary

Some embodiments include an apparatus having a structure with a surface which comprises tungsten. The apparatus has titanium-nitride-containing protective material along and directly against the surface. The structure may be a digit line of a memory array. Some embodiments include a method in which an assembly is formed to have a tungsten-containing layer with an exposed tungsten-containing upper surface. Titanium-nitride-containing protective material is formed over and directly against the tungsten-containing upper surface. Additional material is formed over the protective material, and is spaced from the tungsten-containing upper surface by the protective material. The additional material may comprise silicon nitride and/or silicon dioxide.