ALD Gap Filling with Sidewall Inhibition for High-Aspect-Ratio Voids
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Solution Overview
Problem
Atomic layer deposition (ALD) struggles to effectively fill gaps with high aspect ratios due to void formation, as the entrance of the gap is smaller than the inner portion, leading to incomplete filling.
Innovation Solution
A method involving the formation of a first reaction inhibition layer on the gap's side wall, followed by a density gradient adsorption of a first reactant and subsequent conversion into a second reactant with reduced ligand adsorption, using specific gases like water (H2O) or oxygen (O2) plasma, to create a filling layer that decreases in density towards the gap's bottom, allowing for repeated cycles of precursor and atomic layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If atomic layer deposition (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 local quality by creating a density gradient in the reaction inhibitor adsorption on the gap side wall. The density of the reaction inhibitor is higher at the upper portion and lower at the lower portion of the side wall, which locally adjusts the inhibition effect to prevent void formation while maintaining uniform filling layer thickness.
Solution Approach 2:
The patent uses preliminary action by pre-adsorbing a reaction inhibitor on the gap side wall before performing the ALD filling process. This preliminary inhibition layer prevents unwanted reactions at the side wall while allowing complete filling of the gap, especially addressing the void formation issue in high aspect ratio gaps.
2Reliability
If a reaction inhibition layer is formed on the gap side wall to prevent voids, then void formation is reduced, but the filling process becomes more complex
Solution Approach 1:
The patent applies parameter changes by controlling the density distribution of the reaction inhibitor through adjustment of adsorption conditions (exposure time, temperature, pressure). This creates a gradient density profile that provides effective void prevention while using a single ALD process without additional complex steps.
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 complete filling of gaps with high aspect ratios by minimizing voids, enabling the formation of uniform layers without impurities, suitable for nanostructures and semiconductor devices.
Implementation Method 1
adsorbing a first reaction inhibitor into the side wall of the gap
Implementation Method 2
adsorbing a second reactant into the first precursor layer
Implementation Method 3
removing a specific ligand from the first reaction inhibitor
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 on a side wall of the gap; forming a first precursor layer by adsorbing a first reactant into a 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 by adsorbing a second reactant into the first precursor layer. The forming of the first reaction inhibition layer may include adsorbing a first reaction inhibitor into the side wall of the gap; and forming a second reaction inhibitor by removing a specific ligand from the first reaction inhibitor.