High Aspect Ratio Insulation Layer Densification via RF Plasma
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Solution Overview
Problem
Forming a uniform, high-quality insulation layer on a trench with a high aspect ratio is challenging due to the deterioration of insulating properties when the layer thickness is reduced, especially in achieving step coverage and maintaining quality in the thickness direction.
Innovation Solution
A method involving silicon precursor adsorption, multiple purge steps, and densification using a plasma atmosphere formed by RF power within a specific frequency range (400 kHz to 2 MHz) and output range (100 W to 3 kW), with CCP plasma formation and specific gas sources, to enhance the quality and step coverage of the insulation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the insulation layer thickness is reduced, then the integration density is improved, but the insulating properties deteriorate
Solution Approach 1:
The patent changes the deposition parameters by using atomic layer deposition (ALD) method with specific precursor gases and controlled temperature ranges (200-400°C), achieving superior film quality and uniformity at reduced thickness while maintaining excellent insulating properties through precise parameter control
Solution Approach 2:
The patent utilizes phase transitions of precursor materials from gas phase to adsorbed phase on the trench surfaces, enabling complete and uniform coverage even in high aspect ratio trenches, thereby maintaining high insulating properties at reduced layer thickness
2Volume of moving object
If the insulation layer thickness is reduced, then the integration density is improved, but the uniformity of the layer deteriorates
Solution Approach 1:
The patent employs ALD process parameters including temperature control (200-400°C), pressure control, and sequential precursor introduction to achieve atomic-level uniformity in film thickness across the entire trench structure, overcoming the uniformity challenges associated with reduced thickness
Solution Approach 2:
The patent uses periodic cyclic deposition steps with alternating precursor introduction and purging phases, ensuring complete and uniform coverage on trench surfaces through repeated cycles, thereby achieving excellent uniformity even at reduced layer thickness
3Device complexity
If the aspect ratio of the trench is increased, then the device complexity is reduced, but the step coverage deteriorates
Solution Approach 1:
The patent exploits phase transitions of precursor gases to adsorbed films on vertical trench surfaces, enabling complete coverage of high aspect ratio structures through vapor-phase deposition that naturally conforms to complex geometries, achieving excellent step coverage without increasing device complexity
Solution Approach 2:
The patent replaces mechanical contact-based deposition with vapor-phase chemical deposition, allowing the precursor gases to penetrate and coat the entire trench surface including vertical walls and bottom, thereby achieving superior step coverage on high aspect ratio structures
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 excellent quality and step coverage for the insulation layer, even in trenches with high aspect ratios, by improving the densification and reducing the wet etch rate, resulting in a dense and uniform film.
Implementation Method 1
a densification step of forming a plasma atmosphere in the inside of the chamber by applying an radio frequency (RF) power and densifying the insulation layer including silicon by using the plasma atmosphere
Implementation Method 2
forming a plasma atmosphere in the inside of the chamber by applying an radio frequency (RF) power
Implementation Method 3
an adsorption step of adsorbing silicon to the substrate by injecting a silicon precursor into the inside of a chamber
Data Source
AI summary
Provided is a method of depositing an insulation layer on a trench in a substrate, in which the trench having an aspect ratio of 5:1 or more is formed, including: an insulation layer deposition step of performing an adsorption step of adsorbing silicon to the substrate by injecting a silicon precursor into the inside of a chamber into which the substrate is loaded, a first purge step of removing the unreacted silicon precursor and reaction byproducts from the inside of the chamber, a reaction step of forming the adsorbed silicon as an insulation layer including silicon by supplying a first reaction source to the inside of the chamber, and a second purge step of removing the unreacted first reaction source and reaction byproducts from the inside of the chamber; and a densification step of forming a plasma atmosphere in the inside of the chamber by applying an radio frequency (RF) power and densifying the insulation layer including silicon by using the plasma atmosphere, wherein a frequency of the RF power is in a range of 400 kHz to 2 MHz.