Conformal TiN Thin Films with Post-NH3 Smoothing
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Solution Overview
Problem
The integrated circuit (IC) industry faces challenges in forming titanium nitride (TiN) layers that are both conformal and smooth, with superior electrical and physical properties, especially for high aspect ratio structures and small dimensions.
Innovation Solution
A method of depositing a thin film of titanium nitride (TiN) using cyclical vapor deposition, involving exposure to Ti precursors and ammonia (NH3) at specific flow rates and pressures, with a post-deposition exposure to NH3 at a lower flow rate to reduce particle formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If atomic layer deposition (ALD) is used to form conformal TiN films, then conformality is improved, but surface roughness and electrical conductivity deteriorate
Solution Approach 1:
The deposition process is divided into multiple cycles with alternating precursors (Ti precursor and NH3) to achieve atomic-layer-by-atomic-layer growth, ensuring conformal coverage while controlling surface morphology through precise cycle management
Solution Approach 2:
The patent modifies deposition parameters including temperature, pressure, and precursor flow rates to optimize both conformality and surface quality. Specific parameter ranges are established to achieve the desired balance between film uniformity and surface smoothness
2Manufacturing precision
If atomic layer deposition (ALD) is used to form conformal TiN films, then conformality is improved, but electrical conductivity deteriorates
Solution Approach 1:
Deposition temperature and precursor ratios are optimized to control film density and crystalline structure, achieving lower resistivity while maintaining conformal coverage. The patent establishes specific temperature and flow rate ranges to enhance electrical properties
Solution Approach 2:
The patent employs composite deposition approaches combining multiple precursor systems and deposition conditions to create TiN films with enhanced electrical properties while maintaining the conformal characteristics of ALD
3Productivity
If conventional vapor deposition is used to form TiN films, then deposition speed is improved, but conformality deteriorates
Solution Approach 1:
The continuous deposition process is segmented into discrete cycles with alternating precursor exposures, allowing each cycle to complete full surface coverage before proceeding to the next layer, ensuring conformality even at higher deposition rates
Solution Approach 2:
The patent maintains continuous deposition action through optimized cycle timing and precursor flow management, preventing interruptions that would compromise conformality while maximizing overall deposition throughput
4Productivity
If standard NH3 flow rate is used during deposition, then deposition efficiency is improved, but particle formation increases
Solution Approach 1:
The NH3 flow rate is dynamically adjusted between different stages of the deposition cycle - higher during Ti precursor exposure for efficient reaction, and lower during NH3 exposure to minimize particle formation, optimizing both productivity and film quality
Solution Approach 2:
The deposition process uses periodic alternation between Ti precursor and NH3 exposures with varying flow rates, creating a rhythm that promotes efficient deposition during reactive phases while reducing particle formation during purging and stabilization phases
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 a significant reduction in particles on the TiN thin film, improving its conformality, surface smoothness, and electrical resistivity, while maintaining or exceeding the properties of TiN films formed by traditional PVD and CVD methods.
Implementation Method 1
forming on a semiconductor substrate a TiN thin film without aid of plasma by exposing the semiconductor substrate to one or more cyclical vapor deposition cycles each including an exposure to a Ti precursor and an exposure to ammonia (NH3)
Implementation Method 2
after forming the TiN thin film, subjecting the semiconductor substrate, without deposition of an additional TiN thin film on the thin film, to a post-deposition exposure to NH3 at a second NH3 flow rate, wherein the second NH3 flow rate is lower than the first NH3 flow rate by at least a factor of two
Data Source
AI summary
The disclosed technology generally relates to forming a thin film comprising titanium nitride (TiN), and more particularly to forming by a cyclical vapor deposition process the thin film comprising (TiN). In one aspect, a method of forming a thin film comprising titanium nitride (TiN) by a cyclical vapor deposition process comprises forming on a semiconductor substrate a TiN thin film by exposing the semiconductor substrate to one or more cyclical vapor deposition cycles each comprising an exposure to a Ti precursor at a Ti precursor flow rate and an exposure to a NH3 precursor at a NH3 precursor flow rate, after forming the TiN film, subjecting the semiconductor substrate, without further deposition of the TiN thin film, to a post-deposition exposure of NH3 at a second NH3 flow rate.