Integrated Circuit Barrier Metal Layer for Electrochemical Migration
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Solution Overview
Problem
Integrated circuits with finer line-widths and space-widths are prone to electrochemical migration, leading to short-circuits due to metal ion diffusion under biased voltage and moisture, which limits the reliability of electronic circuits.
Innovation Solution
A barrier metal layer with a lesser reduction potential than the conductive material, such as Nickel or Tin, is applied to the surface of conductive traces using electroless metal plating to slow down metal ion diffusion and prevent the formation of conductive bridges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If finer line-widths and space-widths are used in integrated circuits, then manufacturing precision and circuit density are improved, but electrochemical migration and short-circuit reliability deteriorate
Solution Approach 1:
A barrier metal layer is introduced as an intermediary between the conductive material and the environment. This barrier layer prevents direct interaction between metal ions and moisture, blocking the electrochemical migration pathway while allowing the fine-line circuit geometry to be maintained
Solution Approach 2:
The patent uses composite material structure by combining the conductive material (copper) with a barrier metal layer (nickel or tin). This composite structure leverages the high conductivity of copper while using the corrosion-resistant properties of the barrier metal to prevent electrochemical migration
2Reliability
If electroless metal plating is applied to deposit barrier metal layer, then electrochemical migration is reduced, but manufacturing process complexity increases
Solution Approach 1:
The electroless plating process is a self-service method where the barrier metal deposits automatically onto the conductive material surface through chemical reaction without requiring external power sources or complex equipment. The process uses chemical reduction to deposit the barrier layer uniformly, eliminating the need for additional process control systems
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 barrier metal layer significantly reduces electrochemical migration, enhancing the reliability and longevity of integrated circuits by preventing short-circuits between oppositely polarized conductive traces.
Implementation Method 1
electrochemical migration, leading to short-circuits due to metal ion diffusion under biased voltage and moisture
Implementation Method 2
A barrier metal layer with a lesser reduction potential than the conductive material, such as Nickel or Tin, is applied to the surface of conductive traces using electroless metal plating
Data Source
AI summary
A process for fabricating an Integrated Circuit (IC) and the IC formed thereby is disclosed. The process comprises providing a substrate. The process further comprises forming a plurality of longitudinal trenches in the substrate and depositing a layer of a first conductive material on at least one longitudinal trench of the plurality of longitudinal trenches. A first layer of a second conductive material is deposited on the layer of the first conductive material. Thereafter, the process includes depositing a second layer of the second conductive material on the first layer of the second conductive material. The second layer of the second conductive material at least partially fills the at least one longitudinal trench. The first conductive material is selected such that a reduction potential of the first conductive material is less than a reduction potential of the second conductive material.