Plasma-Treated Barrier and Liner Layers for Low-Resistivity Interconnects
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Solution Overview
Problem
In microelectronic devices, particularly at the 5 nm node and below, the challenge lies in achieving reliable barrier and liner layers for copper interconnects to prevent electromigration failures and improve electrical properties, as traditional techniques are limited by material properties and thickness constraints, leading to increased resistivity and susceptibility to electro-migration failures.
Innovation Solution
A method involving plasma treatment of barrier and liner layers within substrate features, where the barrier layer is not densified before deposition of the liner layer, and both layers are treated with a second plasma to form a treated composite, reducing thickness, increasing grain size, and lowering resistivity, thereby enhancing adhesion and gapfill performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of barrier/liner layers is increased to improve adhesion and reduce electromigration, then adhesion and reliability are improved, but resistivity increases and gapfill space is reduced
Solution Approach 1:
The patent applies plasma treatment to modify the physical and chemical parameters of the barrier and liner layers. Specifically, plasma treatment changes the surface energy, roughness, and microstructure of these layers, which improves adhesion properties and reduces resistivity without requiring increased thickness. This parameter modification approach resolves the contradiction by achieving better electrical and mechanical properties through quality enhancement rather than quantity increase.
Solution Approach 2:
The patent replaces the traditional mechanical approach of increasing layer thickness to improve adhesion with a plasma treatment process. Instead of adding more material mechanically, the invention uses plasma physics to modify existing layer properties, thereby reducing resistivity and improving gapfill performance while maintaining or enhancing adhesion and electromigration resistance.
2Reliability
If the thickness of barrier/liner layers is increased to prevent electromigration failures, then reliability is improved, but the space available for metal gap fill is reduced
Solution Approach 1:
Plasma treatment modifies the microstructure and surface properties of the barrier and liner layers, improving their functional performance for electromigration resistance. This allows the maintenance of thin layer thicknesses while achieving the desired reliability, thereby preserving sufficient space for metal gap fill operations.
3Reliability
If traditional metal or metal alloy liners are used to improve nucleation and bonding, then adhesion is improved, but process complexity and material constraints increase
Solution Approach 1:
The patent extracts the nucleation and bonding enhancement function from the traditional metal alloy liner approach and applies it through plasma treatment instead. This eliminates the need for complex multi-material stackups and reduces process complexity while achieving the same or better adhesion and nucleation performance through a single plasma treatment step.
Solution Approach 2:
The plasma treatment process serves multiple functions simultaneously: it improves adhesion, enhances nucleation, reduces resistivity, and modifies surface roughness. This multi-functionality replaces the need for separate metal alloy liner layers that would otherwise be required to achieve these individual improvements, thereby reducing overall process complexity.
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 plasma treatment method effectively decreases the thickness of barrier and liner layers, lowers resistivity, and improves adhesion and gapfill properties, reducing void volume and facilitating integration, thus addressing electromigration issues and enhancing the reliability of copper interconnects.
Implementation Method 1
treating the liner layer and the barrier layer with a second plasma to form a treated composite
Data Source
AI summary
Embodiments of the disclosure relate to methods for forming electrical interconnects. Additional embodiments provide methods of forming and treating barrier and liner layers to improve film and material properties. In some embodiments, the resulting composite layers provide improved resistivity, decrease void formation and improve device reliability.