Metal Gate Deposition Using Metal-Halide Precursors

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Solution Overview

Problem

Current vapor deposition processes, such as PVD, face limitations in achieving uniformity and process control for metal gate electrodes and barrier layers on large substrates with high aspect ratios, particularly with tantalum materials, which suffer from chlorine contamination and high carbon content when using traditional CVD or ALD processes.

Innovation Solution

The use of thermal decomposition, CVD, pulsed CVD, ALD, and plasma-enhanced processes to deposit metal-containing materials like tantalum, hafnium, and lanthanum, with specific metal-halide precursors and reactive gases to form metal carbides, silicides, and nitrides, ensuring minimal halide and carbon content, and achieving conformal deposition on high k dielectric materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If traditional CVD or ALD processes use TaCl5 as a precursor to deposit tantalum materials, then tantalum materials can be formed, but chlorine contaminants are introduced within the tantalum material

Engineering Contradiction:

Improvetantalum material depositionVSAvoidchlorine contamination

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the harmful chlorine element from the deposition process by replacing TaCl5 precursor with metal-organic precursors that do not contain chlorine, thereby depositing tantalum materials without introducing chlorine contaminants

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses metal-organic precursors as temporary carriers of metal atoms that decompose during deposition, leaving only the desired metal material without persistent harmful residues

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Length of moving object

If PVD processes are used to deposit tantalum materials on features of small size and high aspect ratios, then deposition can be achieved, but the process reaches a limit at this size and aspect ratio

Engineering Contradiction:

Improvefeature sizeVSAvoiddeposition reliability

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent replaces the mechanical physical vapor deposition process with chemical vapor deposition or atomic layer deposition processes, where reactive species chemically deposit material conformally on complex geometries, overcoming the limitations of line-of-sight PVD deposition

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If traditional bottom only deposition approach is used, then process simplicity is maintained, but conformal deposition on bottom and side walls is not achieved

Engineering Contradiction:

Improvedeposition processVSAvoidconformal deposition uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent employs CVD and ALD processes that provide universal conformal deposition capability, depositing material uniformly on all surfaces (bottom and side walls) simultaneously, making the process adaptable to various complex three-dimensional structures

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 enables the formation of metal gate electrodes and barrier layers with improved electronic properties, reduced contamination, and enhanced uniformity, suitable for next-generation semiconductor technologies with increased circuit integration.

Implementation Method 1

The deposition process may include thermal decomposition processes

Methodology Applied

Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 2

chemical vapor deposition (CVD) processes

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Implementation Method 3

plasma enhanced (PE) processes, such as PE-CVD and PE-ALD

Methodology Applied

Scientific EffectPlasma enhanced chemical vapor deposition: Plasma Enhanced Chemical Vapour Deposition

Implementation Method 4

atomic layer deposition (ALD) processes

Methodology Applied

Scientific EffectAtomic layer deposition:

Data Source

PatentUS8642468B2NMOS metal gate materials, manufacturing methods, and equipment using CVD and ALD processes with metal based precursors

Publication Date: 2014.02.04 APPLIED MATERIALS INC

AI summary

Embodiments of the invention generally provide methods for depositing metal-containing materials and compositions thereof. The methods include deposition processes that form metal, metal carbide, metal silicide, metal nitride, and metal carbide derivatives by a vapor deposition process, including thermal decomposition, CVD, pulsed-CVD, or ALD. In one embodiment, a method for processing a substrate is provided which includes depositing a dielectric material having a dielectric constant greater than 10, forming a feature definition in the dielectric material, depositing a work function material conformally on the sidewalls and bottom of the feature definition, and depositing a metal gate fill material on the work function material to fill the feature definition, wherein the work function material is deposited by reacting at least one metal-halide precursor having the formula MXY, wherein M is tantalum, hafnium, titanium, and lanthanum, X is a halide selected from the group of fluorine, chlorine, bromine, or iodine, and y is from 3 to 5.