Post-Dose Treatment for Conformal ALD in High Aspect Ratio Features
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Solution Overview
Problem
Conventional atomic layer deposition (ALD) techniques face challenges in achieving conformal film deposition in high aspect ratio features due to non-uniform precursor and reactant distribution, leading to voids and seams, and existing methods to enhance exposure time or plasma power result in densification and sputtering issues.
Innovation Solution
The method involves a post-dose treatment operation to preferentially remove adsorbed silicon-containing precursor from the tops of features, followed by exposure to a reactant and plasma, allowing for conformal deposition of silicon-containing films like silicon oxide, silicon nitride, and silicon carbide in high aspect ratio structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ALD techniques are used to deposit films in high aspect ratio features, then film deposition occurs, but non-uniform precursor and reactant distribution leads to voids and seams
Solution Approach 1:
The patent applies preliminary action by performing a post-dose treatment operation after precursor exposure but before reactant introduction. This treatment selectively removes excess adsorbed precursor from feature tops using plasma or UV radiation, preventing subsequent film formation at those locations and ensuring uniform reactant distribution for seamless film deposition throughout the feature structure
Solution Approach 2:
The patent implements local quality by creating spatially non-uniform precursor distribution through the post-dose treatment. The treatment selectively modifies the adsorbed precursor layer at different locations: removing it from feature tops while preserving it on sidewalls and bottoms, thereby enabling location-specific film deposition characteristics that achieve conformality without voids or seams
2Manufacturing precision
If plasma power is increased to enhance reactant exposure, then reaction completeness improves, but sputtering increases
Solution Approach 1:
The post-dose treatment performs a preliminary modification of the precursor layer before the main plasma-enhanced deposition reaction. By pre-establishing uniform precursor distribution and removing excess from feature tops, it enables the subsequent plasma reaction to proceed at lower power levels while still achieving complete and uniform film formation, thereby reducing sputtering
Solution Approach 2:
The patent changes the process parameters by introducing a two-stage approach: first a low-power or UV-based post-dose treatment to prepare the precursor layer, then a controlled plasma reaction. This parameter modification allows the main deposition reaction to use lower plasma power than conventional methods while maintaining reaction completeness, thus reducing harmful sputtering effects
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 enables conformal film deposition along sidewalls and bottoms of features while minimizing film formation at the top, preventing voids and seams, and maintaining film quality by controlling the post-dose treatment conditions such as plasma power and ultraviolet radiation.
Implementation Method 1
exposing the patterned substrate to a silicon-containing precursor under conditions allowing the silicon-containing precursor to adsorb onto surfaces of the one or more features, thereby forming an adsorbed layer
Implementation Method 2
exposing the patterned substrate to the reactant and igniting a first plasma to form the silicon-containing film over the patterned substrate
Implementation Method 3
igniting a first plasma to form the silicon-containing film
Implementation Method 4
performing a post-dose treatment operation to preferentially remove the adsorbed layer at tops of the one or more features
Data Source
AI summary
Methods and apparatuses for depositing films in high aspect ratio features and trenches using a post-dose treatment operation during atomic layer deposition are provided. Post-dose treatment operations are performed after adsorbing precursors onto the substrate to remove adsorbed precursors at the tops of features prior to converting the adsorbed precursors to a silicon-containing film. Post-dose treatments include exposure to non-oxidizing gas, exposure to non-oxidizing plasma, and exposure to ultraviolet radiation.