PEALD Silicon Gap Fill Using Continuous Precursor Flow
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Solution Overview
Problem
Existing semiconductor fabrication processes face challenges in efficiently depositing silicon-containing films, particularly in high aspect ratio gaps and 3D structures, with conventional ALD methods being limited by cycle times and reactant flow control, leading to suboptimal growth rates and film uniformity.
Innovation Solution
The method employs plasma-enhanced atomic layer deposition (PEALD) with controlled flow rates and dual frequency RF plasma, allowing silicon-containing precursor flow during purge and plasma exposure phases, and incorporating a CVD-type component to enhance growth rates and film conformality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ALD methods are used to deposit silicon-containing films, then film deposition is achieved, but deposition rates are low and cycle times are long
Solution Approach 1:
The patent maintains continuous flow of silicon-containing precursor throughout the entire ALD cycle including during purge and plasma exposure phases. This continuous presence of precursor enables simultaneous film growth and plasma treatment, eliminating idle time between deposition steps and achieving higher deposition rates while reducing cycle times
Solution Approach 2:
The patent combines multiple functions into overlapping time periods: precursor dosing, purging, and plasma exposure are merged such that precursor flow continues during both purge and plasma phases. This merging of operational phases allows the deposition process to proceed continuously without sequential interruptions, thereby increasing productivity
2Manufacturing precision
If conventional ALD methods are used, then film deposition is achieved, but film uniformity and conformality in high aspect ratio gaps are suboptimal
Solution Approach 1:
The patent applies different process conditions to different regions within the gap structure. By maintaining continuous precursor flow and applying plasma treatment simultaneously, the process achieves uniform film deposition on vertical sidewalls while also filling horizontal gaps, addressing the specific geometric challenges of high aspect ratio structures with localized process optimization
Solution Approach 2:
The patent introduces silicon-containing precursor into the gap structure before plasma exposure begins and maintains its presence during plasma treatment. This preliminary and continuous precursor dosing ensures that reactive sites throughout the gap structure are pre-loaded with precursor, enabling uniform film formation even in difficult-to-reach areas of complex geometries
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 increases deposition rates and improves film uniformity and conformality, effectively filling high aspect ratio gaps and voids in structures like 3D NAND and DRAM, while reducing cycle times.
Implementation Method 1
flowing a silicon-containing precursor into the processing station via the showerhead to allow the silicon-containing precursor to adsorb onto the substrate
Implementation Method 2
exposing the substrate to plasma species to react with the adsorbed silicon-containing precursor
Implementation Method 3
depositing silicon-containing film in the gap by a plasma-enhanced atomic layer deposition (PEALD) process
Implementation Method 4
the plasma in (c) is a dual frequency RF plasma generated using high frequency (HF) and low frequency (LF) RF power
Data Source
AI summary
A method comprising: providing a substrate in a processing station comprising a substrate support and a showerhead, the substrate comprising a gap to be filled; and depositing silicon-containing film in the gap by a plasma-enhanced atomic layer deposition (PEALD) process comprising multiple cycles of operations (a)-(d): (a) a dose operation comprising flowing a silicon-containing precursor into the processing station via the showerhead to allow the silicon-containing precursor to adsorb onto the substrate; (b) after (a), flowing a purge gas into the processing station; (c) after (b), exposing the substrate to plasma species to react with the adsorbed silicon-containing precursor; and (d) after (c), flowing a purge gas into the processing station, wherein the silicon-containing precursor continues to flow into the processing station during at least (b).