TiN PEALD with Direct Microwave Plasma for High-Conformality Films
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Solution Overview
Problem
Current methods for depositing titanium nitride, such as thermal ALD and plasma-enhanced ALD, face challenges including high impurity levels, high resistivity, and poor conformality due to high ion energy and low radical concentration, especially when dealing with complex structures like trenches and holes.
Innovation Solution
The method employs direct microwave plasma-enhanced atomic layer deposition (PEALD) using a titanium precursor and ammonia gas, with sequential exposure and pulsing to achieve superior TiN films with controlled Ti:N ratio, reduced Cl- concentration, and lower film stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal ALD is used to deposit titanium nitride, then the deposition process can be performed, but the films have high impurity levels and high resistivity
Solution Approach 1:
The patent changes the deposition method from thermal ALD to direct microwave plasma-enhanced ALD, fundamentally altering the process parameters (introducing microwave plasma with high radical concentration) to achieve lower impurity levels and resistivity while maintaining film quality
Solution Approach 2:
The patent replaces thermal energy-driven chemical reactions with plasma-driven radical reactions, substituting the thermal field with a plasma field to achieve superior film properties through enhanced radical concentration and reduced ion damage
2Manufacturing precision
If capacitor coupled RF plasma (CCP) is used for PEALD, then plasma enhancement is achieved, but high ion energy causes plasma damage and poor conformality in high aspect ratio structures
Solution Approach 1:
The patent changes the plasma generation method from capacitor coupled RF to direct microwave plasma, fundamentally altering the plasma parameters (lower ion energy, higher radical concentration) to eliminate plasma damage while achieving excellent conformality in high aspect ratio structures
Solution Approach 2:
The patent replaces capacitor coupled RF plasma generation with direct microwave plasma generation, substituting the electromagnetic field coupling mechanism to achieve a plasma environment with reduced ion damage and enhanced radical-based chemistry for better film conformality
3Object-affected harmful factors
If remote plasma (RPS) is used for PEALD, then ion-free radical-based deposition is achieved, but low radical concentration limits deposition efficiency
Solution Approach 1:
The patent replaces remote plasma generation with direct microwave plasma generation, substituting the plasma source location and generation mechanism to achieve both high radical concentration (improving deposition efficiency) and ion-free conditions (maintaining damage avoidance)
Solution Approach 2:
The patent uses microwave radiation as an intermediary to generate plasma directly in the reaction chamber, enabling high radical concentration without the limitations of remote plasma transport, thus simultaneously achieving high deposition efficiency and ion-free conditions
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 provides titanium nitride films with improved conformality, reduced ion damage, and tunable composition, resistivity, and stress, outperforming traditional methods by enhancing radical concentration and plasma density without substrate damage.
Implementation Method 1
direct microwave plasma generated from a plasma gas
Implementation Method 2
direct microwave plasma generated from a plasma gas
Implementation Method 3
sequential exposure of a substrate surface within a processing volume to a titanium precursor and a direct microwave plasma generated from a plasma gas
Implementation Method 4
sequential exposure of a substrate surface within a processing volume to a titanium precursor, ammonia gas, and a direct microwave plasma generated from a plasma gas
Data Source
AI summary
A method of depositing titanium nitride is disclosed. Some embodiments of the disclosure provide a PEALD process for depositing titanium nitride which utilizes a direct microwave plasma. In some embodiments, the direct microwave plasma has a high plasma density and low ion energy. In some embodiments, the plasma is generated directly above the substrate surface.