ALD Gap Filling Using Density-Gradient Sidewall Inhibition
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Solution Overview
Problem
Atomic layer deposition (ALD) struggles to fill gaps with high aspect ratios effectively, often resulting in voids due to the size discrepancy between the gap entrance and its inner portion.
Innovation Solution
A method involving the formation of a first reaction inhibition layer with a density gradient on the gap side walls, followed by the sequential adsorption of reactants to form a first atomic layer on the gap bottom and side walls, facilitating efficient filling in a bottom-up direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ALD is used to fill gaps, then uniform thickness filling layer is formed on surfaces around the gap, but voids are formed when the gap has a high aspect ratio
Solution Approach 1:
The patent applies preliminary action by forming a reaction inhibition layer on the side walls of the gap before performing the ALD filling process. This pre-formed layer prevents the filling material from depositing on the side walls, ensuring that material only accumulates at the bottom of the gap, thereby enabling complete void-free filling of high aspect ratio gaps while maintaining uniform thickness control
Solution Approach 2:
The patent implements local quality by creating a density gradient in the reaction inhibition layer, where the density varies from the top to the bottom of the gap. This localized variation in density allows the layer to effectively block material deposition at different positions along the side walls, ensuring precise control over where the filling material accumulates and preventing void formation in high aspect ratio structures
2Shape
If the gap has a high aspect ratio, then the entrance size becomes smaller than the inner portion size, but conventional ALD cannot fill such gaps effectively
Solution Approach 1:
The reaction inhibition layer is formed in advance on the side walls before the ALD filling process begins. This preliminary structure prevents material from adhering to the side walls during deposition, allowing the filling material to accumulate exclusively at the gap bottom and progressively fill upward, thereby enabling effective filling of high aspect ratio gaps with varying cross-sectional dimensions
Solution Approach 2:
The patent utilizes parameter changes by controlling the density gradient of the reaction inhibition layer. By adjusting the density distribution within the inhibition layer, the process optimizes material deposition patterns, ensuring that filling material accumulates at the bottom and progresses upward to completely fill high aspect ratio gaps with entrance sizes smaller than their inner portions
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 minimizes void formation by ensuring uniform filling of high aspect ratio gaps, enhancing the precision and effectiveness of the ALD process.
Implementation Method 1
forming a first reaction inhibition layer by adsorbing a reaction inhibitor onto a side wall of the gap
Implementation Method 2
forming a first precursor layer by adsorbing a first reactant onto the bottom of the gap and the side wall of the gap around the bottom of the gap
Implementation Method 3
forming a first atomic layer on the bottom of the gap and the side wall of the gap around the bottom of the gap. The forming the first atomic layer includes adsorbing the second reactant onto the first precursor layer
Implementation Method 4
For ALD, a surface reaction is used
Data Source
AI summary
A method and an apparatus for filling a gap by using an atomic layer deposition (ALD) method are provided. The method includes forming a first reaction inhibition layer by adsorbing a reaction inhibitor onto a side wall of the gap, forming a first precursor layer by adsorbing a first reactant onto the bottom of the gap and the side wall of the gap around the bottom of the gap, and forming a first atomic layer on the bottom of the gap and the side wall of the gap around the bottom of the gap. The reaction inhibitor includes a precursor material that does not react with a second reactant. The first reaction inhibition layer may have a density gradient in which a density of the reaction inhibitor decreases toward a bottom of the gap. The forming the first atomic layer includes adsorbing the second reactant onto the first precursor layer.