Conformal ALD SiO2 Film Formation Using Spatial Inhibitor Gradient
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Solution Overview
Problem
Conformal growth of dielectric films within features such as trenches during atomic layer deposition (ALD) processes is challenging due to non-uniform precursor distribution and growth rates, leading to incomplete film filling and quality issues.
Innovation Solution
The introduction of an inhibitor material during the ALD process, which decreases in density from the top to the bottom of the trenches, suppresses film growth and allows for a more conformal deposition by controlling the interaction of precursor molecules, thereby reducing the growth rate and ensuring complete filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ALD process is used for dielectric film deposition in trenches, then film formation occurs, but conformal growth is challenging due to non-uniform precursor distribution and growth rates
Solution Approach 1:
The patent introduces an inhibitor material with spatially varying density (higher at trench top, lower at bottom) to create local differences in film growth suppression. This local quality variation enables conformal deposition by compensating for non-uniform precursor distribution - the inhibitor suppresses growth more strongly at the trench opening where precursor concentration is higher, while allowing better growth penetration to the trench bottom where precursor concentration is lower.
Solution Approach 2:
The patent changes the growth rate parameter through the introduction of inhibitor material during the ALD process. By controlling the inhibitor density gradient, the effective growth rate is modulated spatially within the trench structure, enabling conformal film formation. The growth rate decreases as inhibitor density increases, allowing precise control over film thickness uniformity.
2Quantity of substance
If precursor molecules are introduced during ALD process, then dielectric film is formed, but non-uniform precursor distribution leads to incomplete film filling in trenches
Solution Approach 1:
The inhibitor material acts as an intermediary substance that mediates the interaction between precursor molecules and the substrate surface within trenches. By introducing this intermediary with controlled spatial distribution, the patent enables more uniform precursor utilization and achieves consistent film thickness throughout the trench structure, from top to bottom.
3Manufacturing precision
If ALD cycle is repeated to increase film thickness, then more complete trench filling is achieved, but growth rate varies leading to quality issues
Solution Approach 1:
The patent employs periodic introduction of inhibitor material during repeated ALD cycles. This periodic action maintains controlled growth suppression throughout the deposition process, ensuring that each cycle contributes uniformly to film thickness buildup. The cyclic inhibitor introduction pattern enables sustained conformal growth while maintaining reasonable deposition rates.
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 method enables high-quality, conformal dielectric film deposition within trenches, maintaining the shape and structure of the substrate features and improving the overall film quality and thickness consistency.
Implementation Method 1
Atomic layer deposition (ALD) is based upon atomic layer epitaxy (ALE) and employs chemisorption techniques to deliver precursor molecules on a substrate surface in sequential cycles
Implementation Method 2
The cycle exposes the substrate surface to a first precursor and then to a second precursor. The first and second precursors react to form a product compound as a film on the substrate surface
Data Source
AI summary
Embodiments of the disclosure provide a method of forming a dielectric film in trenches of a substrate. The utilization of the ALD process and introduction of an inhibitor material onto features defining the trenches and into the trenches provides for suppression of forming the dielectric film near the top surface of the features in the trenches. The dielectric film is formed via an ALD process. The ALD process includes sequentially exposing the substrate to an inhibitor material, a first precursor, a purge gas, an oxygen-containing precursor, and the purge gas during an ALD cycle, and repeating the ALD cycle to deposit the dielectric film.