Catalyst-Enhanced Molybdenum Deposition for Void-Free Gap Fill
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Solution Overview
Problem
Current semiconductor manufacturing techniques face challenges in achieving void-free gap filling and low resistivity in metal films, particularly for Molybdenum (Mo) films, due to issues like rough surfaces, high temperature requirements, and material instability, which hinder the miniaturization of semiconductor devices.
Innovation Solution
The method involves exposing a substrate with features to alternating pulses of a zero-valent metal arene precursor and an alkyl halide catalyst, maintaining the substrate at a specific temperature to form a metal film on the bottom of the feature while ensuring the sidewalls remain dielectric, using atomic layer deposition (ALD) to achieve a seam-free gap fill with high purity metal films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CVD process is used for metal film deposition, then deposition occurs all over the structure, but voids and seams are formed in the gap due to roughness
Solution Approach 1:
The patent applies local quality by making deposition selective to specific locations (bottom of features) while preventing deposition on sidewalls. This is achieved through catalyst placement that enables bottom-up growth only at the feature bottom, ensuring gap fill without voids or seams.
Solution Approach 2:
The patent uses preliminary action by first depositing a catalyst layer on the substrate before metal film deposition. This catalyst layer is selectively removed from sidewalls, preparing the structure for selective bottom-up metal growth that fills gaps without forming voids.
2Ease of manufacture
If high temperature deposition is used for Mo films, then deposition can proceed with common precursors, but surface roughness increases and chamber stability decreases
Solution Approach 1:
The patent changes the temperature parameter from high (>550°C) to low (<450°C) deposition conditions. This parameter change enables the use of alternative precursors and catalysts that provide smooth surface deposition while maintaining processability through the catalyst-enhanced chemical vapor deposition mechanism.
3Reliability
If Ru is used as fill material, then low resistivity is achieved, but material instability occurs under high temperature causing pull-up and bottom voids
Solution Approach 1:
The patent uses a disposable catalyst layer that is intentionally deposited and then selectively removed. This temporary catalyst enables low-temperature Mo deposition with smooth surfaces, and its removal prevents the material instability and pull-up issues seen with Ru, achieving both low resistivity and thermal stability.
4Manufacturing precision
If atomic scale precision deposition is implemented, then manufacturing accuracy improves, but process complexity increases and throughput decreases
Solution Approach 1:
The patent merges multiple functions into a single integrated process: catalyst deposition, catalyst patterning, and selective metal film growth are combined in one sequence. This integration achieves atomic-scale precision while maintaining throughput by eliminating separate complex process 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 results in smoother, lower resistance metal films that conformally fill gaps without seams, enabling precise atomic-scale deposition and reducing manufacturing costs by improving throughput and material stability.
Implementation Method 1
A substrate having at least one feature comprising a bottom and sidewalls is exposed to alternating pulses of a zero-valent metal arene precursor and an alkyl halide catalyst. The substrate is maintained at a deposition temperature to form a metal film on the bottom of the feature.
Implementation Method 2
The metal precursor has a decomposition temperature above the deposition temperature.
Data Source
AI summary
Methods of depositing a metal film are discussed. A metal film is formed on the bottom of feature having a metal bottom and dielectric sidewalls. Formation of the metal film comprises exposure to a metal precursor and an alkyl halide catalyst while the substrate is maintained at a deposition temperature. The metal precursor has a decomposition temperature above the deposition temperature. The alkyl halide comprises carbon and halogen, and the halogen comprises bromine or iodine.