Fluorine-Inhibited PEALD of Silicon Nitride and Oxide for Gap Fill
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Solution Overview
Problem
Conventional plasma-enhanced atomic layer deposition (PEALD) methods for silicon nitride and silicon oxide deposition in high aspect-ratio features suffer from void formation due to radical recombination at sidewalls, leading to poor conformality and gap-fill issues.
Innovation Solution
A method involving the use of fluorine reactants, silicon precursors, and nitrogen/oxygen reactants, optionally with hydrogen, in controlled plasma environments to enhance deposition, with specific timing and sequencing to promote uniform coverage across feature tops and bottoms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional PEALD methods are used to deposit silicon nitride or silicon oxide, then deposition can be performed at relatively low temperatures with high deposition rates, but voids form in high aspect-ratio features due to radical recombination at sidewalls
Solution Approach 1:
The patent introduces a fluorocarbon-containing reactant that selectively deposits fluorocarbon species at different locations within the feature. The fluorocarbon species accumulate at the sidewalls and top surfaces where radical recombination occurs, locally modifying the deposition behavior to prevent void formation while maintaining overall deposition rate
Solution Approach 2:
The fluorocarbon-containing reactant acts as an intermediary substance that mediates between the plasma radicals and the substrate surface. It provides fluorocarbon species that inhibit radical recombination at critical locations, enabling conformal deposition in high aspect-ratio features while maintaining the benefits of PEALD
2Manufacturing precision
If process parameters are tuned to provide adequate activated species near the bottom of features, then conformality improves, but plasma near the bottom increases which is undesired for recent device manufacturing specifications
Solution Approach 1:
The patent converts the harmful effect of plasma exposure at the bottom of features into a beneficial outcome. By introducing fluorocarbon-containing reactant, the plasma that would normally cause void formation is transformed into a source of fluorocarbon species that inhibit further radical recombination, thereby preventing voids while maintaining low plasma conditions
3Quantity of substance
If nitrogen plasma is used to form species at the top of features, then material deposition at the top increases, but voids and seams still form in higher aspect ratio gaps and wet etch rate becomes undesirably high
Solution Approach 1:
The patent changes the chemical parameters of the deposition process by introducing fluorocarbon-containing reactant. This modifies the surface chemistry and deposition kinetics, allowing control over material distribution and wet etch rate while preventing void formation through fluorocarbon species inhibition of radical recombination
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 method achieves improved conformality and gap-fill capability, reducing void formation and enhancing deposition uniformity in high aspect-ratio features.
Implementation Method 1
providing a precursor into a reaction chamber to form adsorbed species on a surface of a substrate
Implementation Method 2
plasma-enhanced process, such as plasma-enhanced ALD (PEALD)
Implementation Method 3
exposing the adsorbed species to a nitrogen plasma to form species at the top of the feature that include nitrogen
Data Source
AI summary
Methods of depositing material on a surface of a substrate are disclosed. The methods include using a fluorine reactant to reduce a growth rate per cycle of silicon oxide and/or silicon nitride deposited onto a surface of a substrate.