SiN Plasma Condensation for Void-Free Gap Fill at Low Temperature
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Solution Overview
Problem
Existing flowable films for semiconductor devices face challenges in void-free filling of gaps and trenches, requiring elevated deposition and cure temperatures, complex pattern loading, and high wet etch rates, leading to integration issues.
Innovation Solution
A plasma treatment process is applied to a silicon nitride-based dielectric film, involving a reactive gas reaction and bias plasma to form a condensed silicon nitride film, followed by curing at low temperatures to improve mechanical properties and reduce etch rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional steam annealing, UV irradiation, hot pressing, or sintering at high temperatures is used to harden flowable films, then the dielectric film is formed, but elevated deposition temperatures (>200°C) and elevated cure temperatures (>500°C) are required
Solution Approach 1:
The patent changes the physical and chemical parameters of the dielectric film through plasma treatment. By applying plasma at low temperatures, the film undergoes condensation and curing without requiring high temperature annealing (>500°C) or complex multi-step processes. The plasma process modifies the film's density, reduces Si-H and N-H bonds, and achieves the desired dielectric properties at temperatures below 200°C
Solution Approach 2:
The patent replaces the conventional thermal-mechanical hardening process (steam annealing, hot pressing, sintering) with a plasma-based chemical-physical process. Instead of using high temperature and pressure to densify the film, plasma radiation and reactive species are used to condense and cure the dielectric material, eliminating the need for elevated deposition temperatures and complex mechanical pressing equipment
2Manufacturing precision
If flowable films are used to fill gaps and trenches, then void-free filling is achieved, but high wet etch rates lead to downstream integration issues
Solution Approach 1:
The patent changes the chemical composition and physical structure of the dielectric film through plasma treatment. The plasma process reduces Si-H and N-H bonds while increasing film density and cross-linking, which fundamentally alters the film's etch resistance. This parameter change transforms the film from having high wet etch rate to having etch resistance comparable to or exceeding conventional CVD silicon nitride, while maintaining the void-free filling capability
Solution Approach 2:
The patent creates a composite structure within the dielectric film by combining flowable precursor materials with plasma-treated condensed phases. The resulting film has heterogeneous properties: the base material provides void-free filling capability, while the plasma-induced condensed regions provide enhanced etch resistance and mechanical strength, achieving both low etch rate and good fill characteristics
3Manufacturing precision
If conventional flowable films are deposited, then gap filling is performed, but complex pattern loading controllability is required for bottom-up growth rate between narrow and wide opening critical dimensions
Solution Approach 1:
The patent replaces complex process control mechanisms with a self-regulating plasma deposition process. Instead of using multiple deposition cycles, temperature variations, or pressure adjustments to control bottom-up growth in different pattern densities, the plasma process inherently provides uniform deposition and condensation across all feature sizes. The reactive plasma species and ion bombardment automatically adapt to local geometry, eliminating the need for complex pattern loading algorithms and process tuning
4Strength
If plasma treatment is applied to form condensed silicon nitride film, then etch rate is reduced and mechanical properties are improved, but additional processing steps are required
Solution Approach 1:
The patent merges the deposition and condensation/curing steps into a single integrated plasma process. The plasma treatment is applied in-situ immediately after dielectric precursor deposition, combining the film formation and property enhancement into one continuous operation. This eliminates separate annealing, curing, or densification steps that would otherwise be required, reducing overall process complexity while achieving improved mechanical properties and etch resistance
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 process enables uniform deposition and bottom-up fill in narrow openings, reduces Si—H and N—H bonds, lowers the dielectric constant, and enhances electrical properties by improving hardness and reducing etch rates, suitable for filling structures in 3D NAND, 3D DRAM, and CFET devices.
Implementation Method 1
A plasma is provided to the processing chamber, in which the dielectric precursor reacts with a reactive gas in the plasma to form a silicon nitride (SiN)-based dielectric film on the substrate
Implementation Method 2
A bias plasma is applied to the silicon nitride (SiN)-based dielectric film to form a condensed silicon nitride (SiN)-based dielectric film
Implementation Method 3
The condensed dielectric film is cured
Data Source
AI summary
Embodiments described herein generally relate to methods of post-treating a silicon-nitride (SiN)-based dielectric film formed on a surface of a substrate. The methods include positioning a substrate in a processing chamber. A dielectric precursor is supplied to the processing chamber. A plasma is provided to the processing chamber, in which the dielectric precursor reacts with a reactive gas in the plasma to form a silicon nitride (SiN)-based dielectric film on the substrate. A bias plasma is applied to the silicon nitride (SiN)-based dielectric film to form a condensed silicon nitride (SiN)-based dielectric film. The condensed dielectric film is cured