Variable Dopant Interconnects for Electromigration Reliability
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Solution Overview
Problem
Copper interconnects in microelectronics face reliability issues due to electromigration, which is exacerbated by the addition of dopants like manganese that improve reliability but increase electrical resistance, posing a challenge in balancing reliability and performance.
Innovation Solution
The implementation of interconnect structures with varying dopant concentrations at the same wiring level, where signal interconnects have a low dopant concentration and power interconnects have a high dopant concentration, achieved through the use of different seed layers and trench designs such as microtrenches to control dopant segregation and minimize resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dopants such as manganese are added to copper interconnects, then electromigration reliability is improved, but interconnect resistance significantly increases
Solution Approach 1:
The patent applies local quality by implementing different dopant concentrations in different interconnect lines at the same wiring level. Specifically, power interconnects receive a first dopant concentration optimized for electromigration resistance, while signal interconnects receive a second dopant concentration optimized for low resistance. This allows each interconnect type to have locally optimized properties tailored to its specific functional requirements, resolving the contradiction between reliability and resistance.
2Ease of manufacture
If uniform dopant concentration is used across all interconnects, then manufacturing process is simplified, but performance is compromised due to increased resistance in signal lines
Solution Approach 1:
The patent implements local quality through selective dopant application where different regions (power vs. signal interconnects) receive different dopant concentrations. The manufacturing process uses separate doping steps or selective masking techniques to apply the first dopant concentration to power interconnects and the second dopant concentration to signal interconnects, achieving locally optimized performance without sacrificing overall manufacturability.
Solution Approach 2:
The patent applies segmentation by dividing the interconnect network into distinct categories (power interconnects and signal interconnects) and applying different dopant concentrations to each category. This segmentation allows the manufacturing process to treat different interconnect types differently, optimizing each for its specific function while maintaining a systematic approach to dopant application.
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 enhances electromigration reliability while maintaining low electrical resistance, thereby improving the performance and reliability of integrated circuits by optimizing dopant distribution within interconnects.
Implementation Method 1
the selective incorporation of dopants into conductive lines
Implementation Method 2
Copper-based interconnect technology
Implementation Method 3
electromigration-induced failure over time
Data Source
AI summary
Interconnect structures and related methods of manufacture improve device reliability and performance by selectively incorporating dopants into conductive lines. Multiple seed layer deposition steps or variable trench bottom areas are used to locally control the dopant concentration within the interconnect structures at the same wiring level, which provides a robust integration approach for metallizing interconnects in future-generation technology nodes.