Area-Selective ALD Passivation via Block Molecule Reaction
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Solution Overview
Problem
The semiconductor industry faces challenges in device miniaturization due to issues with selective deposition methods, particularly in area-selective atomic layer deposition (AS-ALD), where the deposited film may grow sideways (mushrooming) reducing selectivity and requiring additional complex fabrication steps.
Innovation Solution
A method involving the use of block I and block II molecules, where block I molecules with alkyne or alkene groups are deposited on metal surfaces and react with block II molecules containing azide or thiol groups to form a passivation layer, preventing further deposition and allowing selective ALD on dielectric surfaces, thereby enhancing selectivity and avoiding mushrooming effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional AS-ALD is used to deposit passivation layers, then selectivity is initially maintained, but the deposited film grows sideways (mushrooming) reducing selectivity when the film becomes thicker than the self-assembled monolayers
Solution Approach 1:
The patent applies preliminary action by performing surface pretreatment to create self-assembled monolayers (SAMs) on non-growth surfaces before the main deposition process. This preliminary SAM formation prevents sideways growth (mushrooming) of the ALD film, maintaining deposition selectivity even as film thickness increases. The SAMs are formed in advance to establish protective barriers that constrain subsequent film growth to intended areas only.
2Manufacturing precision
If process parameters are modulated to control chemical kinetics for selective deposition, then selectivity is improved, but processing time and process complexity increase
Solution Approach 1:
The patent employs parameter changes by systematically modulating process parameters including pressure, substrate temperature, precursor partial pressures, and gas flows to control the chemical kinetics of surface reactions. These parameter adjustments enable selective deposition on target surfaces while preventing deposition on non-growth surfaces. The optimized parameter ranges achieve high selectivity without requiring excessive processing time by finding the optimal balance point for each parameter.
3Manufacturing precision
If additional lithography steps are added to maintain selectivity during miniaturization, then device fabrication precision is maintained, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the need for additional lithography steps by implementing area-selective atomic layer deposition as a standalone patterning and deposition method. The AS-ALD process inherently provides the selectivity and precision previously requiring separate lithography and deposition steps. By taking out the lithography requirement, the patent simplifies the fabrication process while maintaining the ability to create precise nanoscale features and patterns during device miniaturization.
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 enables the growth of thicker AS-ALD films with improved selectivity, reducing the need for additional lithography or etching processes and maintaining processing time efficiency by using a two-module processing system for flexible and compatible polymer passivation layers.
Implementation Method 1
reacting the block I molecule with a block II molecule to form a passivation layer on the metal surface
Implementation Method 2
forming a passivation layer on the metal surface... preventing further deposition
Implementation Method 3
block I molecule comprising one or more of an alkyne and an alkene... block II molecule comprising one or more of an azide and a thiol
Data Source
AI summary
Methods of enhancing selective deposition are described. In some embodiments, a passivation layer is deposited on a metal surface before deposition of a dielectric material. A block I molecule is deposited on a metal surface, and a block II molecule is reacted with the block I molecule to form a passivation layer.