Hydrophobic Layer for Semiconductor Interconnect Reliability
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Solution Overview
Problem
Semiconductor devices face reliability issues due to weak adhesion at Cu/capping layer interfaces, surface contamination, and degradation of low k dielectric materials, leading to leakage currents, voltage breakdown, and reduced time-dependent dielectric breakdown (TDDB) performance.
Innovation Solution
The process involves cleaning the copper surface, applying a metal or metal alloy cap, and forming a hydrophobic layer on the dielectric surface to prevent contamination and moisture uptake, using methods such as thermal treatment, plasma cleaning, and chemisorbing silane-based hydrophobic layers to enhance adhesion and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capping layer is placed on the Cu surface to prevent Cu oxidation and migration, then Cu protection is improved, but adhesion at the Cu/capping layer interface deteriorates
Solution Approach 1:
A hydrophobic layer is introduced as an intermediary between the Cu/capping layer interface and the external environment. This layer serves as a mediator that prevents harmful substances (moisture, oxygen, contaminants) from reaching the interface, thereby maintaining both protection and adhesion without requiring direct modification of the interface itself
Solution Approach 2:
The harmful environmental factors (moisture, oxygen, contaminants) are excluded from the Cu/capping layer interface by applying the hydrophobic layer. This effectively removes the threat of oxidation and adhesion degradation without altering the intrinsic properties of the interface
2Object-generated harmful factors
If wet chemical or oxidative plasma clean processes are used to prevent surface contamination, then cleaning effectiveness is improved, but dielectric layer degradation worsens
Solution Approach 1:
Instead of using harsh cleaning processes that damage the dielectric layer, a hydrophobic layer is applied that converts the potentially harmful interface into a protected surface. The hydrophobic layer acts as a sacrificial barrier that prevents contamination without requiring aggressive cleaning that would degrade the dielectric
Solution Approach 2:
The hydrophobic layer serves as an intermediary that protects the dielectric layer from direct exposure to contaminants. Rather than directly cleaning the dielectric surface (which causes damage), the hydrophobic layer indirectly prevents contamination by repelling water and water-soluble substances
3Object-generated harmful factors
If low k dielectric materials are used to reduce leakage current, then dielectric performance is improved, but mechanical strength and moisture resistance deteriorate
Solution Approach 1:
The hydrophobic layer acts as a protective intermediary between the low k dielectric material and the external environment. It mediates the interaction by repelling moisture and contaminants, thereby protecting the mechanically weak dielectric without requiring changes to its low k properties that would increase leakage current
Solution Approach 2:
A thin hydrophobic film is applied over the low k dielectric material. This flexible protective shell provides mechanical reinforcement and moisture barrier functionality without significantly altering the electrical properties of the underlying dielectric, thus maintaining low leakage current while improving strength and moisture resistance
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 significantly reduces moisture uptake, improves adhesion, and enhances the reliability of semiconductor devices by minimizing leakage currents and extending TDDB performance.
Implementation Method 1
forming a hydrophobic layer on the dielectric surface to prevent contamination and moisture uptake
Implementation Method 2
plasma cleaning
Implementation Method 3
chemisorbing silane-based hydrophobic layers
Implementation Method 4
thermal treatment
Data Source
AI summary
A semiconductor system includes: providing a dielectric layer; providing a conductor in the dielectric layer, the conductor exposed at the top of the dielectric layer; capping the exposed conductor; and modifying the surface of the dielectric layer, modifying the surface of the dielectric layer, wherein modifying the surface includes cleaning conductor ions from the dielectric layer by dissolving the conductor in a low pH solution, dissolving the dielectric layer under the conductor ions, mechanically enhanced cleaning, or chemisorbing a hydrophobic layer on the dielectric layer.