Interconnect Barrier Layer Structure for Metal Diffusion Blocking
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Solution Overview
Problem
In semiconductor devices, metal diffusion through multiple barrier layers poses challenges, affecting the performance and reliability of interconnect structures, particularly in preventing metal elements from conductive lines from reaching the pad layer.
Innovation Solution
A multi-layer barrier structure comprising nano-crystalline, amorphous, and poly-crystalline tantalum or titanium nitride layers is formed conformally around conductive lines to prevent metal diffusion, with specific thickness ratios and deposition techniques ensuring effective blocking of metal elements during thermal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple barrier layers are used to prevent metal diffusion, then reliability is improved, but device complexity increases
Solution Approach 1:
The barrier layer is segmented into multiple distinct layers with different crystal phases (amorphous, nano-crystalline, poly-crystalline) and compositions. Each layer serves as an independent barrier against metal diffusion, creating a multi-stage defense system that blocks metal elements at multiple interfaces, thereby enhancing overall reliability through layered protection.
Solution Approach 2:
The barrier structure employs composite materials combining different tantalum-based compounds (tantalum nitride, tantalum oxide, tantalum oxynitride) in specific phases and ratios. This composite approach leverages the complementary properties of each material phase to achieve superior metal diffusion resistance that cannot be obtained with a single material system.
2Manufacturing precision
If conformal barrier layers with specific thickness ratios are deposited, then manufacturing precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The invention specifies precise thickness parameters for each barrier layer (first layer: 5-20 nm, second layer: 20-50 nm, third layer: 50-100 nm) and controls the ratio between them. By defining specific parameter ranges and ratios, the patent achieves controlled metal diffusion blocking while providing clear manufacturing guidelines that balance precision requirements with process feasibility.
Solution Approach 2:
The barrier layers are deposited conformally on the conductive lines before subsequent processing steps. This preliminary formation of the multi-layer barrier structure ensures that metal diffusion prevention is established early in the manufacturing sequence, preventing contamination during later high-temperature or metal-deposition processes.
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 multi-layer barrier structure significantly reduces the failure rate of semiconductor structures by effectively blocking metal diffusion to the pad layer, maintaining electrical performance and reliability.
Implementation Method 1
A multi-layer barrier structure comprising nano-crystalline, amorphous, and poly-crystalline tantalum or titanium nitride layers is formed conformally around conductive lines to prevent metal diffusion
Implementation Method 2
with specific thickness ratios and deposition techniques ensuring effective blocking of metal elements during thermal processes
Implementation Method 3
with specific thickness ratios and deposition techniques ensuring effective blocking of metal elements during thermal processes
Data Source
AI summary
A semiconductor structure includes a conductive line, a pad layer, and a barrier layer. The conductive line is embedded in a multi-level interconnect structure. The pad layer is over the conductive line. The barrier layer is between the conductive line and the pad layer. The pad layer is electrically connected to the conductive line through the barrier layer, and the barrier layer includes a first poly-crystalline layer and a second poly-crystalline layer. A boundary is between the first poly-crystalline layer and the second poly-crystalline layer.