Room-Temperature Liquid Cobalt Complex for Oxidation-Free CVD Deposition

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Solution Overview

Problem

Current methods for producing cobalt-containing thin films in semiconductor devices face challenges with the use of solid cobalt complexes, which can decompose under high temperatures, leading to inconsistent vaporization, clogging, and contamination, and require oxidizing gases, while also risking conduction failure due to oxidation of silicon or copper wiring.

Innovation Solution

A novel cobalt complex that is liquid at room temperature, allowing for the production of cobalt-containing thin films without using oxidizing gases, specifically using a reducing gas, and is stable for vapor deposition methods like CVD and ALD, ensuring consistent supply and preventing oxidation-related issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If solid cobalt complexes are used as CVD/ALD materials, then the material can be supplied in a stable form, but the material requires high temperature heating which causes decomposition and inconsistent vaporization

Engineering Contradiction:
Improvematerial stabilityVSAvoidvaporization consistency
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent changes the physical state parameter of the cobalt complex from solid to liquid at room temperature. This fundamental parameter change allows the material to vaporize consistently at lower temperatures without decomposition, resolving the contradiction between maintaining material stability and achieving reliable vaporization. The liquid state at room temperature enables controlled vaporization through temperature and pressure adjustments without requiring high-temperature heating that would cause decomposition.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If solid cobalt complexes are used, then the material can be stored stably, but transport and supply cause clogging and contamination problems

Engineering Contradiction:
Improvestorage stabilityVSAvoidmaterial transport
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent changes the physical state from solid to liquid at room temperature, which fundamentally improves material transport characteristics. The liquid state eliminates clogging issues in transport lines and prevents particle contamination that occurs with solid materials. The material can be pumped and transported smoothly like a fluid, while maintaining storage stability through controlled conditions.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If oxidizing gases are used in the vapor deposition process, then the deposition process can proceed efficiently, but oxidation of silicon or copper wiring causes conduction failure

Engineering Contradiction:
Improvedeposition efficiencyVSAvoidelectrical conduction
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent employs an inert or reducing atmosphere instead of oxidizing gases during the vapor deposition process. This creates a protective environment that prevents oxidation of the cobalt complex during vaporization and prevents oxidation of underlying silicon or copper wiring layers. The inert atmosphere maintains both deposition efficiency and electrical conduction reliability by eliminating harmful oxidation reactions.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

4Speed

If high temperature heating is applied to vaporize solid cobalt complexes, then sufficient vaporization rate can be achieved, but the material decomposes due to prolonged heating

Engineering Contradiction:
Improvevaporization rateVSAvoidmaterial decomposition
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent changes the physical state from solid to liquid, which dramatically lowers the vaporization temperature requirement. The liquid cobalt complex can achieve sufficient vaporization rates at much lower temperatures compared to solid materials, eliminating the need for high-temperature heating that causes decomposition. This parameter change decouples vaporization rate from high-temperature requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes the phase transition properties of the liquid cobalt complex to achieve controlled vaporization. The liquid state at room temperature allows for gradual phase transition to vapor phase at controlled rates through mild heating or pressure reduction, preventing the thermal decomposition that occurs with solid materials requiring high-temperature phase transitions.

Inventive Principle:
Principle #36Phase transitions

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 cobalt complex enables the production of high-quality cobalt-containing thin films with improved thermal stability and uniformity, preventing oxidation-related conduction failures and ensuring efficient film deposition without the need for oxidizing gases, thus enhancing the reliability and performance of semiconductor devices.

Implementation Method 1

it is required to keep the material at high temperature of at least the melting point for the purpose of keeping the vaporization rate to be sufficient and constant

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 2

these compounds may be decomposed by heating for a long time

Methodology Applied
Scientific EffectThermal decomposition: Decomposition (biological)

Implementation Method 3

production of a cobalt-containing thin film under conditions using a reducing gas

Methodology Applied
Scientific EffectReduction: Reduction

Data Source

PatentEP3882234B1Cobalt complex, method for manufacturing same, and method for manufacturing cobalt-containing thin film
Publication Date: 2024.05.08 TOSOH CORP
  • EP3882234B1 patent drawingFigure 1~2
  • EP3882234B1 patent drawingFigure 3~4
  • EP3882234B1 patent drawingFigure 5~6

AI summary

To provide a cobalt complex which is liquid at room temperature, useful for producing a cobalt-containing thin film under conditions without using an oxidizing gas. A cobalt complex represented by the following formula (1):         L1-Co-L2     (1) wherein L1 and L2 represent a unidentate amide ligand of the following formula (A), a bidentate amide ligand of the following formula (B) or a hetero atom-containing ligand of the following formula (C): wherein R1 and R2 represent a C1-6 alkyl group or a tri(C1-6 alkyl)silyl group, and the wave line represents a binding site to the cobalt atom; wherein R3 represents a tri(C1-6 alkyl)silyl group, R4 and R5 represent a C1-4 alkyl group, and X represents a C1-6 alkylene group; wherein R6 and R8 represent a C1-6 alkyl group, R7 represents a hydrogen atom or a C1-4 alkyl group, Y represents an oxygen atom or NR9, Z represents an oxygen atom or NR10, and R9 and R10 independently represent a C1-6 alkyl group.