Selective Silicon Nitride Deposition Without Vacuum Breaks
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Solution Overview
Problem
Current methods for forming 3D-NAND devices result in poor-quality silicon nitride films due to low temperature selective deposition, which is insufficient for high-quality SiN films needed for enhanced carrier mobility and differentiation between ON and OFF cells.
Innovation Solution
A processing method involving pre-cleaning, pre-treating, and selectively depositing a silicon-containing dielectric layer in a vacuum environment, followed by densification, using a cluster tool with integrated chambers for each step, to form high-quality silicon nitride films on polysilicon sidewalls or silicon nitride surfaces without breaking vacuum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If selective deposition is used to eliminate patterning steps, then manufacturing complexity is reduced, but film quality deteriorates due to low deposition temperatures
Solution Approach 1:
The surface is pre-treated with a growth inhibitor before deposition to create selective regions that promote film growth only in desired areas. This preliminary surface modification enables selective deposition at lower temperatures while maintaining film quality, resolving the contradiction between process simplicity and film quality.
Solution Approach 2:
The deposition temperature is changed from high temperature (required for quality films) to low temperature (enabling selective deposition), and compensation is achieved through surface pre-treatment and growth inhibitor application. This parameter change allows selective deposition to produce high-quality films without requiring high temperatures.
2Manufacturing precision
If high temperature deposition is used to form quality silicon nitride films, then film quality is improved, but additional patterning steps are required increasing process complexity
Solution Approach 1:
The surface undergoes pre-treatment with growth inhibitors that create spatially selective regions before deposition. This preliminary action allows the subsequent low-temperature deposition to be selective, eliminating the need for high-temperature deposition and subsequent patterning steps.
Solution Approach 2:
The high-temperature deposition step and subsequent patterning steps are extracted from the process flow. Instead, a low-temperature selective deposition process is implemented through surface pre-treatment, removing the complex high-temperature processing sequence while maintaining film quality.
3Device complexity
If low temperature deposition is used for selective silicon nitride formation, then patterning steps are eliminated, but wet etch rate and surface roughness deteriorate
Solution Approach 1:
The surface is pre-treated with growth inhibitors that modify surface chemistry to enable selective film growth. This preliminary action creates conditions where low-temperature deposition produces films with improved wet etch rates and surface roughness characteristics, overcoming the limitations of low-temperature deposition.
Solution Approach 2:
The deposition temperature is reduced from high to low, and compensatory changes are made in surface preparation and growth inhibitor application. These parameter changes enable selective deposition at low temperature while achieving acceptable wet etch rates and surface roughness.
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 enables the formation of high-quality silicon-containing dielectric layers with improved wet etch rates and surface roughness reduction, essential for efficient 3D-NAND device performance.
Implementation Method 1
pre-treating the top surface of the film stack to form a treated surface
Implementation Method 2
exposing the treated surface to a growth inhibitor
Implementation Method 3
selectively depositing a silicon-containing dielectric layer in a region of the film stack
Implementation Method 4
densifying the silicon-containing dielectric layer
Data Source
AI summary
Methods of manufacturing electronic devices, e.g., logic devices or memory devices, are provided. The method comprises pre-cleaning a top surface of a film stack, the film stack comprising alternating layers of a first material layer and a second material layer and having one or more of a memory hole and a slit pattern opening extending through the film stack; pre-treating the top surface of the film stack to form a treated surface; exposing the treated surface to a growth inhibitor; selectively depositing a silicon-containing dielectric layer in a region of the film stack; and densifying the silicon-containing dielectric layer. The processing method is performed in a processing tool without breaking vacuum.