Cyclical Molybdenum Film Deposition on Dielectrics With Nucleation Layers
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Solution Overview
Problem
Current semiconductor device fabrication processes require conformal deposition of low electrical resistivity metal films, such as tungsten and copper, which often necessitate thick barrier layers that increase overall resistivity due to high electrical resistivity.
Innovation Solution
A cyclical deposition process is used to deposit a molybdenum metal film directly on a nucleation film, which is itself deposited on a dielectric surface, eliminating the need for high resistivity barrier layers by using a molybdenum halide precursor and a reducing agent precursor in a vapor phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick barrier layer is used to prevent metal diffusion into dielectric material, then device reliability is improved, but overall electrical resistivity increases
Solution Approach 1:
The patent extracts and eliminates the thick barrier layer from the conventional metal film structure. By using molybdenum metal film deposited directly on the dielectric surface without a thick barrier layer, the invention removes the source of high electrical resistivity while maintaining device reliability through the inherent properties of the cyclical deposition process that produces continuous, low-resistivity films
Solution Approach 2:
The patent changes the deposition parameters by using cyclical deposition processes (such as ALD or CCVD) with specific vapor phase reactants. This enables the formation of ultra-thin, continuous molybdenum films with low electrical resistivity directly on the dielectric surface, eliminating the need for thick barrier layers and thereby reducing overall electrical resistivity while maintaining reliability
2Manufacturing precision
If conformal deposition is used to uniformly deposit metal film over three-dimensional structures, then deposition uniformity is improved, but process complexity increases
Solution Approach 1:
The patent employs cyclical deposition processes where vapor phase reactants are introduced sequentially in periodic cycles. Each cycle consists of alternating exposure to different reactants (e.g., molybdenum precursor followed by reducing agent), enabling precise control over film formation. This periodic action achieves conformal deposition with atomic-level thickness control while maintaining manageable process complexity through automated cycle control
Solution Approach 2:
The patent uses vapor phase reactants as intermediaries to achieve conformal deposition. The first vapor phase reactant (molybdenum halide precursor) and second vapor phase reactant (reducing agent precursor) act as mediators that sequentially react on the substrate surface, enabling uniform metal film formation over three-dimensional structures without requiring complex deposition equipment or processes
3Reliability
If ultra-thin continuous metal film is deposited, then electrical conductivity is improved, but deposition precision requirements increase
Solution Approach 1:
The cyclical deposition process introduces reactants in controlled periodic cycles, with each cycle depositing a precise amount of material. This periodic control enables the formation of ultra-thin continuous films with precise thickness control at the atomic level, achieving the required deposition precision while maintaining excellent electrical conductivity through continuous film formation
Solution Approach 2:
The patent changes the deposition approach by using vapor phase reactants in cyclical processes rather than conventional continuous deposition. This enables precise control over film thickness and continuity, achieving ultra-thin films with atomic-level precision while maintaining low electrical resistivity through continuous, pinhole-free film formation
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 method achieves lower effective electrical resistivity for interconnects in logic and memory applications by providing a conformal, continuous molybdenum metal film with reduced surface roughness and impurity concentration, enhancing device performance and reliability.
Implementation Method 1
depositing the molybdenum metal film comprises: contacting the substrate with a first vapor phase reactant comprising a molybdenum halide precursor; and contacting the substrate with a second vapor phase reactant comprising a reducing agent precursor
Data Source
AI summary
Methods for depositing a molybdenum metal film over a dielectric surface of a substrate by a cyclical deposition process are disclosed. The methods may include: providing a substrate comprising a dielectric surface into a reaction chamber; depositing a nucleation film directly on the dielectric surface; and depositing a molybdenum metal film directly on the nucleation film, wherein depositing the molybdenum metal film includes: contacting the substrate with a first vapor phase reactant comprising a molybdenum halide precursor; and contacting the substrate with a second vapor phase reactant comprising a reducing agent precursor. Semiconductor device structures including a molybdenum metal film disposed over a surface of a dielectric material with an intermediate nucleation film are also disclosed.