IC Interconnect Barrier Structure for Low Resistance and Diffusion Control
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Solution Overview
Problem
The continued scaling of interconnect lines in semiconductor devices leads to increased resistance and metal diffusion issues, posing challenges for manufacturing low-power, high-performance integrated circuits (ICs) with complex functions.
Innovation Solution
Incorporating barrier structures with a thin interconnect portion and a contact portion in interconnect lines to reduce resistance and prevent metal diffusion to underlying contact structures, utilizing a thin profile of about 0.5 nm to 3 nm for the interconnect portion and extending the contact portion 10% to 50% of the ILD layer thickness to act as a metal diffusion barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If interconnect lines are scaled down to increase storage capacity and processing speed, then device density and performance are improved, but resistance increases and metal diffusion problems worsen
Solution Approach 1:
The interconnect line is segmented into multiple functional portions: a first portion with a first thickness and a second portion with a second thickness. This segmentation allows different sections to optimize for different functions - one section for low resistance and another for diffusion prevention, resolving the contradiction between maintaining conductivity and preventing metal diffusion during scaling.
Solution Approach 2:
Different portions of the interconnect line are assigned different local properties - the first portion has a first thickness optimized for electrical conductivity, while the second portion has a second thickness optimized for preventing metal diffusion. This local differentiation allows each section to perform its specific function optimally without compromising the other.
2Quantity of substance
If interconnect lines are scaled down to increase device density, then storage capacity is improved, but metal diffusion to contact structures increases
Solution Approach 1:
The interconnect line is divided into distinct segments where the second portion specifically addresses metal diffusion prevention. This segmentation enables the structure to maintain high device density through scaling while the dedicated second portion acts as a barrier against metal diffusion to underlying contact structures.
Solution Approach 2:
The second portion of the interconnect line acts as an intermediary barrier between the conductive first portion and the underlying contact structures. This intermediate section prevents direct metal diffusion while maintaining electrical connectivity, resolving the harmful effect of metal diffusion during density scaling.
3Ease of manufacture
If a thin barrier structure is used to prevent metal diffusion, then manufacturing complexity is reduced, but resistance increases
Solution Approach 1:
Rather than using a single thin barrier layer that would increase resistance, the solution segments the interconnect line into two portions with different thicknesses. The first portion maintains low resistance for conductivity, while the second portion provides diffusion prevention. This segmentation achieves protection without sacrificing electrical performance.
Solution Approach 2:
The interconnect line uses local quality differentiation where the first portion has optimized thickness for conductivity and the second portion has optimized thickness for diffusion prevention. This local optimization allows the structure to maintain ease of manufacture through simple geometric variation rather than complex multi-layer barriers.
4Reliability
If the interconnect portion thickness is reduced to minimize resistance, then electrical performance is improved, but metal diffusion prevention capability decreases
Solution Approach 1:
The interconnect line is segmented into a first portion with reduced thickness for low resistance and a second portion with increased thickness for diffusion prevention. This segmentation resolves the contradiction by assigning different thickness optimizations to different sections, allowing both electrical performance and diffusion prevention to be maximized simultaneously.
Solution Approach 2:
Different local sections of the interconnect line have different thickness properties - the first portion has thin profile for electrical performance while the second portion has thick profile for metal diffusion prevention. This local quality differentiation allows each section to optimize for its specific function without compromising the other.
Data Source
AI summary
An integrated circuit (IC) with conductive structures and a method of fabricating the IC are disclosed. The method includes depositing a first dielectric layer on a semiconductor device, forming a conductive structure in the first dielectric layer, removing a portion of the first dielectric layer to expose a sidewall of the conductive structure, forming a barrier structure surrounding the sidewall of the conductive structure, depositing a conductive layer on the barrier structure, and performing a polishing process on the barrier structure and the conductive layer.