Oxide Gapfill Pulsing for Void-Free High-Aspect-Ratio Recesses
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Solution Overview
Problem
The miniaturization of semiconductor devices has made it challenging to achieve void-free filling of high aspect ratio gaps or trenches due to limitations in existing deposition processes, particularly in depositing conductive materials that minimize seam and gap formation.
Innovation Solution
A method for depositing an oxide in a recess of a substrate involves pulsing an inhibitor to preferentially deposit it at the opening of the recess, followed by pulsing a precursor to chemisorb on the inner surface, and then pulsing an oxygen species to form the oxide. This process is repeated to achieve the desired thickness, with the inhibitor being used to control deposition and minimize seam formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition processes are used to fill high aspect ratio gaps, then the deposition process is simple, but void-free filling becomes increasingly difficult and seam formation occurs
Solution Approach 1:
The deposition process is segmented into multiple sequential steps: inhibitor deposition step, precursor pulse step, and oxygen species pulse step. Each step performs a specific function - the inhibitor step prevents deposition at openings, the precursor step chemisorbs on inner surfaces, and the oxygen step forms the oxide. This segmentation enables precise control over material deposition locations, achieving void-free filling of high aspect ratio features.
Solution Approach 2:
The inhibitor is deposited onto the substrate surface before the precursor is introduced. This preliminary action creates a protective layer that selectively blocks deposition at the opening while leaving the inner surface available for subsequent precursor chemisorption. The inhibitor deposition prepares the surface in advance to guide the precursor and oxygen species into the recess, ensuring complete filling without seams or voids.
2Productivity
If the recess opening is small relative to depth, then feature density increases, but existing deposition processes cannot achieve void-free filling
Solution Approach 1:
The inhibitor provides localized protection specifically at the recess opening and upper regions, while the inner surface and bottom remain unaffected and available for precursor chemisorption. This local quality differentiation allows the deposition process to selectively fill the deep recess while maintaining control at the opening, enabling void-free filling even in high aspect ratio features where the opening is small relative to depth.
Solution Approach 2:
The inhibitor acts as an intermediary substance that mediates between the precursor/oxygen species and the substrate surface. It selectively interacts with the opening region to prevent unwanted deposition, while allowing the precursor and oxygen species to access and react with the inner surface. This intermediary role enables precise control over the deposition location, achieving complete filling of high aspect ratio features.
3Ease of manufacture
If conventional deposition is used, then process steps are fewer, but seam and gap formation occurs in high aspect ratio trenches
Solution Approach 1:
The deposition process uses periodic pulsing of different gases in a cyclic manner: inhibitor pulse, precursor pulse, oxygen species pulse, and purge steps. This periodic action allows each substance to interact with the substrate under optimized conditions, ensuring complete and uniform filling. The cyclic repetition of these steps builds up the oxide layer incrementally, preventing seam and gap formation while maintaining process control.
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 effectively fills high aspect ratio features with a conductive oxide layer, reducing seam and gap formation while ensuring efficient deposition, thus addressing the challenges posed by miniaturization in semiconductor manufacturing.
Implementation Method 1
pulsing an inhibitor into the chamber to preferentially deposit the inhibitor in a portion of the recess adjacent to at least one opening of the recess and on at least a portion of the surface area
Implementation Method 2
pulsing a precursor into the chamber to chemisorb to the inner surface within the recess
Implementation Method 3
pulsing an oxygen species into the chamber to form the oxide within the recess upon contact with the chemisorbed precursor
Data Source
AI summary
Methods and systems are disclosed for depositing an oxide in a recess of a substrate, including providing the substrate in a chamber, the substrate including at least one opening to the recess where the at least one opening is bordered by a perimeter in a surface area adjacent to and outside of the recess, where the recess includes an inner surface, pulsing an inhibitor into the chamber to preferentially deposit the inhibitor in a portion of the recess adjacent to at least one opening of the recess and on at least a portion of the surface area, pulsing a precursor into the chamber to chemisorb to the inner surface within the recess, pulsing an oxygen species into the chamber to form the oxide within the recess upon contact with the chemisorbed precursor, and repeating the above recited steps to deposit the oxide to a desired thickness level within the recess.