Selective Epitaxial Growth for Void-Free Gap Fill
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Solution Overview
Problem
Conventional deposition processes face challenges in reliably filling high aspect ratio features such as vias and trenches with submicron dimensions, often resulting in poor step coverage, overhangs, seams, and voids, especially at dimensions below 30 nm, due to high temperature requirements and inefficiencies in gap-fill processes.
Innovation Solution
A method involving a multi-mode deposition process with alternating gas ratios of dichlorosilane to HCl gas in a processing chamber, maintaining substrate temperatures between 600°C and 1000°C, to achieve conformal epitaxial layer deposition, controlling deposition profiles and preventing early closure of openings by switching between fast and slow deposition rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition processes are used to fill high aspect ratio features, then deposition can proceed, but poor step coverage, overhangs, seams, and voids occur due to high aspect ratios exceeding 10:1
Solution Approach 1:
The patent applies dynamics by switching between two deposition modes (first mode with higher deposition rate and second mode with lower deposition rate) during the epitaxial growth process. This dynamic adjustment of deposition rate allows the process to adapt to different filling stages, ensuring void-free filling of high aspect ratio features while maintaining deposition continuity and avoiding the defects associated with static single-mode deposition
Solution Approach 2:
The patent changes deposition parameters by adjusting the ratio of dichlorosilane gas to HCl gas in the gas mixture between different deposition modes. This parameter change enables control over the deposition rate, allowing optimization of the filling process for high aspect ratio features while maintaining film uniformity and avoiding deposition discontinuity
2Manufacturing precision
If high temperature process is used for gap-fill, then filling of high aspect ratio features can be achieved, but thermal budget is exceeded and manufacturing cost increases
Solution Approach 1:
The patent changes the chemical parameters of the deposition process by using a specific gas mixture ratio of dichlorosilane to HCl and optimizing deposition conditions to enable low-temperature epitaxial growth. This allows achieving void-free gap-fill of high aspect ratio features at temperatures within the thermal budget (600°C to 1000°C) without requiring high temperature processes that would exceed device thermal limits
Solution Approach 2:
The patent replaces thermal-mechanical deposition mechanisms with chemical epitaxial growth mechanisms. By using selective epitaxial growth with controlled gas phase chemistry, the process achieves effective gap-fill without relying on high temperature thermal fields, thus substituting a thermal process with a chemically-controlled process that operates within lower temperature constraints
3Manufacturing precision
If high temperature process is used for gap-fill, then deposition can proceed, but overall process time increases and manufacturing cost increases
Solution Approach 1:
The patent applies dynamics by implementing a multi-mode deposition process that switches between different deposition rates. The first mode with higher deposition rate quickly builds up the initial layer, while the second mode with lower deposition rate ensures precise filling and void-free completion. This dynamic approach reduces overall process time compared to using a single slow deposition rate throughout, while maintaining high deposition quality
Solution Approach 2:
The patent uses periodic action by alternating between two deposition modes during the epitaxial growth process. This periodic switching between faster and slower deposition phases enables efficient filling of high aspect ratio features, reducing total process time while ensuring void-free completion and maintaining film uniformity throughout the deposition
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 ensures void-free, seam-free, and conformal filling of high aspect ratio features, improving film uniformity and reducing manufacturing costs by maintaining low thermal budgets and efficient process times.
Implementation Method 1
supplying a gas mixture having a ratio of a dichlorosilane gas to a HCl gas between about 1:10 and about 10:10 in an epitaxial growth chamber to deposit an epitaxial layer
Implementation Method 2
maintaining a temperature of a substrate disposed in the processing chamber to between about 600 degrees Celsius and about 1000 degrees Celsius
Data Source
AI summary
Methods and apparatuses for filling an epitaxial layer into a trench/via/structure formed in a substrate with good deposition profile control and film uniformity across the substrate are provided In one embodiment, a method of depositing a epitaxial layer on the substrate includes supplying a gas mixture having a first ratio of a dichlorosilane gas to a chlorine containing gas into the processing chamber, altering the gas mixture to have a second ratio of the dichlorosilane gas to the chlorine containing gas into the processing chamber, maintaining a substrate temperature of between about 600 degrees Celsius and about 1000 degrees Celsius, and filling an opening formed in a substrate.