Tungsten Fill Inhibition Gas Pulsing to Prevent Line Bending

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Solution Overview

Problem

Conventional tungsten deposition processes face challenges in filling narrow features with low fluorine content, reduced resistance, and preventing line bending due to tungsten-tungsten bonding interactions, which lead to device failure and yield loss in semiconductor fabrication.

Innovation Solution

The method involves exposing the deposited tungsten to an inhibition gas, such as nitrogen, oxygen, or ammonia, during the deposition process to disrupt metal-metal bonding and reduce line bending, while using sequential CVD or ALD techniques to control film properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If tungsten is deposited in narrow features using conventional processes, then the features can be filled, but line bending occurs due to tungsten-tungsten bonding interactions

Engineering Contradiction:

Improveline bending preventionVSAvoiddevice failure

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

An inhibition gas (nitrogen, oxygen, or ammonia) is introduced as an intermediary substance during tungsten deposition. This gas adsorbs onto the tungsten surface, preventing direct tungsten-tungsten bonding interactions that cause line bending, while still allowing controlled deposition to proceed

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The deposition process parameters are changed by controlling the inhibition gas pressure and composition during deposition. By adjusting these parameters, the bonding interactions are modulated to prevent line bending while maintaining deposition efficiency

Inventive Principle:

Principle #35Parameter changes

2Productivity

If conventional CVD is used to deposit tungsten rapidly, then productivity is improved, but fluorine content increases and manufacturing precision deteriorates

Engineering Contradiction:

Improvedeposition rateVSAvoidfluorine content control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The deposition process uses periodic alternation between tungsten-containing precursor exposure and inhibition gas exposure. This periodic action allows rapid deposition during precursor pulses while the inhibition gas pulses control fluorine incorporation and prevent line bending

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The inhibition gas is present continuously or near-continuously during the deposition process, ensuring that fluorine content is controlled throughout the entire deposition sequence while maintaining high productivity through rapid precursor delivery

Inventive Principle:

Principle #20Continuity of useful action

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 results in tungsten films with low fluorine content, reduced resistance, and minimized line bending, ensuring uniformity and reliability of semiconductor devices.

Implementation Method 1

the nitrogen gas reduces tungsten-tungsten bonding interactions between tungsten formed on sidewalls of each feature

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

Deposition of tungsten-containing materials is an integral part of many semiconductor fabrication processes

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Data Source

PatentUS20250323045A1Method for preventing line bending during metal fill process

Publication Date: 2025.10.16 LAM RES CORP

AI summary

Provided herein are methods and apparatuses for reducing line bending when depositing a metal such as tungsten, molybdenum, ruthenium, or cobalt into features on substrates by periodically exposing the feature to nitrogen, oxygen, or ammonia during atomic layer deposition, chemical vapor deposition, or sequential chemical vapor deposition to reduce interactions between metal deposited onto sidewalls of a feature. Methods are suitable for deposition into V-shaped features.