Interconnect Barrier Deposition With Metal-Selective Blocking Layers
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Solution Overview
Problem
Current self-assembled monolayers fail to inhibit tantalum nitride growth on aluminum oxide surfaces, leading to reduced electrical performance in electronic devices.
Innovation Solution
Form a blocking layer on metal surfaces using silanes or blocking molecules like 1,2-phenylenebis(trimethylsilane) to selectively deposit a barrier layer on dielectric or aluminum oxide/aluminum nitride surfaces, followed by removing the blocking layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If self-assembled monolayers are used to inhibit tantalum nitride growth on metal surfaces, then selective deposition is improved, but the monolayers also inhibit tantalum nitride growth on aluminum oxide surfaces which reduces electrical performance
Solution Approach 1:
The patent applies local quality by using different surface treatments for different surfaces: silane-based blocking layers are applied selectively to metal surfaces (tungsten, cobalt, copper) while aluminum oxide surfaces receive different pretreatments. This allows the barrier layer deposition to be selective to metal surfaces only, preventing the unwanted inhibition on aluminum oxide etch stop layers while maintaining selectivity on metal surfaces.
Solution Approach 2:
The patent changes the chemical parameters of the surface treatment by using silane-based chemistry (such as trimethylsilane, tetramethylsilane, or phenylenebis(trimethylsilane)) instead of traditional oxygen or nitrogen-based SAMs. This parameter change in the chemical composition of the blocking layer provides selective inhibition on metal surfaces while being removable or incompatible with aluminum oxide surfaces, thus resolving the contradiction.
2Manufacturing precision
If bifunctional SAMs are used to reduce tantalum nitride growth on metal surfaces, then barrier layer selectivity is improved, but they also inhibit tantalum nitride growth on aluminum oxide surfaces
Solution Approach 1:
The patent implements local quality by differentiating the surface preparation and blocking layer formation process between metal surfaces and aluminum oxide surfaces. Metal surfaces undergo silane-based blocking while aluminum oxide surfaces undergo different pretreatment, ensuring that the barrier layer is selective to metal surfaces only and does not inhibit deposition on aluminum oxide etch stop layers.
Solution Approach 2:
The silane-based blocking layer acts as a temporary, disposable protective layer that is applied to metal surfaces only to prevent unwanted barrier layer deposition during the barrier formation process. This blocking layer is subsequently removed or remains selective, allowing the process to proceed without affecting aluminum oxide surfaces.
3Productivity
If conventional SAMs are used for selective deposition, then lithographic steps can be removed, but they fail to provide sufficient selectivity between metal and dielectric surfaces
Solution Approach 1:
The patent changes the chemical parameters by using silane-based chemistry (trimethylsilane, tetramethylsilane, phenylenebis(trimethylsilane)) with specific molecular structures and bonding characteristics. These silane-based blocking layers provide enhanced selectivity between metal and dielectric surfaces compared to conventional SAMs, enabling precise control of barrier layer deposition while maintaining fabrication efficiency.
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
Reduces via resistance by at least 20% and improves electrical performance by selectively depositing tantalum nitride on dielectric surfaces relative to metal surfaces.
Implementation Method 1
exposing a feature extending into a semiconductor substrate to a silane having a general formula of R(4-n)Si(CH3)n to form a blocking layer. The blocking layer forms selectively on the metal surface over the dielectric surface and one of the aluminum oxide surface or the aluminum nitride surface
Implementation Method 2
selectively depositing a barrier layer on the dielectric surface and one of the aluminum oxide surface or the aluminum nitride surface over the blocking layer
Data Source
AI summary
Methods of forming semiconductor devices by enhancing selective deposition are described. In some embodiments, a blocking layer is deposited on a metal surface before deposition of a barrier layer. The methods include exposing a substrate with a metal surface, a dielectric surface and an aluminum oxide surface or an aluminum nitride surface to a blocking molecule to form the blocking layer selectively on the metal surface over the dielectric surface and one of the aluminum oxide surface or the aluminum nitride surface.