Silicon Oxide Gap Fill Expansion for Seam-Free 3D NAND
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Solution Overview
Problem
Conventional plasma enhanced chemical vapor deposition processes for filling large area gaps in high aspect ratio structures in memory devices result in seam and void formation, leading to cracking and other defects during downstream processing.
Innovation Solution
A method involving atomic layer deposition of a silicon-containing precursor film, followed by plasma treatment and cyclic alternation with an oxygen-containing compound to form an oxide gap fill material with a volume 1.1 to 2.0 times greater than the expansion film, reducing seam and void formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional PECVD processes are used to deposit silicon-containing films for large area gap fill, then the gap filling can be achieved, but seam and void formation occurs leading to cracking and defects
Solution Approach 1:
The patent changes the deposition parameters by using atomic layer deposition (ALD) instead of conventional PECVD, controlling temperature, pressure, and precursor delivery to achieve conformal film deposition without seams or voids in high aspect ratio structures
Solution Approach 2:
The patent utilizes the phase transition of silicon-containing precursors from gas phase to solid film phase through controlled chemical reactions in ALD cycles, enabling precise film formation that eliminates defects associated with conventional PECVD
2Productivity
If silicon-containing films are deposited and subsequently etched to form memory openings, then connections can be formed, but cracking and other defects occur during downstream processing
Solution Approach 1:
The patent performs preliminary film deposition using ALD with controlled stoichiometry to create a defect-free silicon-containing film before subsequent etching and connection formation, preventing cracking issues in downstream processing
Solution Approach 2:
The patent replaces the mechanical stress-prone conventional PECVD deposition mechanism with a chemically-controlled ALD process, eliminating the mechanical defects that lead to cracking during subsequent processing steps
3Productivity
If high aspect ratio structures are used for density scaling, then memory capacity is increased, but processing challenges including seam and void formation increase
Solution Approach 1:
The patent changes the deposition methodology to ALD with precisely controlled temperature, pressure, and precursor parameters, enabling successful fabrication of high aspect ratio structures without the seam and void formation that complicates processing
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 high-quality, seam-free and void-free gap fill in 3D NAND structures, enhancing structural integrity and reducing cracking, while maintaining low processing temperatures.
Implementation Method 1
An expansion film is formed by treating the precursor film with a plasma
Implementation Method 2
Currently, large area gap fill is done using plasma enhanced chemical vapor deposition processes to deposit silicon-containing films
Implementation Method 3
An oxygen-containing compound is delivered to the expansion film to form an oxide gap fill material having a volume that is about 1.1 to about 2.0 greater than the expansion film
Data Source
AI summary
The present disclosure provides methods. The methods include forming a precursor film by delivering a precursor to a substrate in a processing chamber having a high aspect ratio opening defining a gap between two or more features of the substrate. An expansion film is formed by treating the precursor film with a plasma. An oxygen-containing compound is delivered to the expansion film to form an oxide gap fill material having a volume that is about 1.1 to about 2.0 greater than an expansion film.