Global Dielectric and Barrier Layer for Semiconductor Devices
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Solution Overview
Problem
The semiconductor industry faces challenges with silicon carbide's low etch selectivity and copper diffusion into tungsten, affecting yield and reliability in IC manufacturing, as existing methods struggle to maintain efficient processing and manufacturing complexity with scaling down.
Innovation Solution
A global transformable (GT) layer is introduced, which acts as both an etch stop and barrier layer, formed from metal nitrides that self-transform into conductive or dielectric materials based on the substrate, preventing premature oxidation and ensuring high etch selectivity and preventing diffusion during the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If silicon carbide is used as an etch stop layer and copper barrier layer, then manufacturing process is simplified, but etch selectivity is low and copper diffuses into tungsten
Solution Approach 1:
The patent divides the barrier layer into multiple segments: a first barrier layer (e.g., tantalum nitride) deposited on the tungsten plug, and a second barrier layer (e.g., silicon nitride) deposited on the oxide layer. This segmentation allows each layer to perform its specific function optimally - the first barrier layer prevents copper diffusion into tungsten, while the second provides etch selectivity as an etch stop layer, resolving the contradiction between process simplicity and functional performance.
Solution Approach 2:
The patent introduces a transformable layer that can serve multiple functions: it acts as a barrier to copper diffusion, provides etch selectivity, and can transform from a conductive state to an insulating state based on processing conditions. This multi-functionality replaces the need for separate silicon carbide and copper barrier layers, simplifying the manufacturing process while maintaining reliability.
2Reliability
If copper is used as interconnect material, then conductivity is improved, but copper diffuses into tungsten plugs
Solution Approach 1:
The patent introduces a first barrier layer (e.g., tantalum nitride) as an intermediary between the copper interconnect and the tungsten plug. This intermediary layer physically separates copper from tungsten, preventing copper atoms from diffusing into the tungsten lattice while maintaining electrical conductivity through the barrier layer, thus preserving the benefits of copper interconnects without the harmful diffusion effect.
Solution Approach 2:
The patent employs composite barrier structures combining different materials with complementary properties. The first barrier layer uses materials with high copper diffusion barrier properties (e.g., tantalum nitride), while the second barrier layer uses materials optimized for etch selectivity (e.g., silicon nitride). This composite approach ensures both conductivity maintenance and diffusion prevention.
3Device complexity
If silicon carbide is used as barrier layer, then process is simplified, but etch selectivity is low
Solution Approach 1:
The patent applies different material properties to different locations in the structure. The first barrier layer (e.g., tantalum nitride) is specifically positioned on the tungsten plug where copper diffusion prevention is critical, while the second barrier layer (e.g., silicon nitride) is positioned on the oxide layer where etch selectivity is needed. This local optimization of material properties resolves the contradiction between structural simplicity and etching precision.
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
The GT layer enhances etch selectivity and prevents diffusion, improving manufacturing efficiency and reliability by maintaining conductive properties on metal features while transforming into a dielectric on oxide layers, thus addressing the limitations of silicon carbide and copper diffusion issues.
Implementation Method 1
the GT layer comprises a metal nitride and transforms by oxidation
Data Source
AI summary
A semiconductor device including a substrate having a dielectric layer over the substrate and a first conductive feature disposed within the dielectric layer. A metal nitride material is disposed directly on a top surface of the first conductive feature. A metal oxynitride material is disposed directly on a top surface of the dielectric layer, wherein the metal nitride and the metal oxynitride are coplanar. A second conductive feature is disposed over and interfacing the metal nitride material.