Multilayer TiN Barrier via Plasma Treatment
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Solution Overview
Problem
As semiconductor technologies advance, the shrinking size of vias in wafer-level chip scale packages demands thinner barrier layers to prevent copper diffusion, but the thickness of these layers affects electrical characteristics such as contact resistance.
Innovation Solution
A multilayer barrier structure is formed using Titanium Nitride (TiN) layers with alternating plasma treatments to reduce carbon impurities and achieve a total thickness of less than 250 Angstroms, improving resistance while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the barrier layer thickness is reduced to accommodate smaller via sizes, then the via size can be reduced, but the contact resistance increases
Solution Approach 1:
The barrier layer is divided into multiple thin sub-layers (first barrier layer, second barrier layer, third barrier layer) with alternating plasma treatment layers in between. This segmentation allows each sub-layer to be optimized for specific functions: copper diffusion barrier and electrical conductivity, while the plasma treatment layers remove carbon impurities that would otherwise increase contact resistance. The total thickness can be reduced while maintaining or improving electrical performance.
Solution Approach 2:
Different regions of the barrier structure have different compositions and properties. The barrier layers provide copper diffusion barrier properties, while the plasma treatment layers provide carbon removal capabilities. This local differentiation of properties allows the structure to simultaneously achieve thin thickness, low contact resistance, and effective copper diffusion prevention.
2Volume of moving object
If a thin barrier layer is used to accommodate smaller via sizes, then the via size can be reduced, but copper diffusion prevention becomes more difficult
Solution Approach 1:
The barrier function is distributed across multiple thin barrier layers rather than relying on a single thick layer. Each barrier layer sub-layer contributes to copper diffusion prevention, and the cumulative effect of multiple layers provides sufficient barrier protection even when the total thickness is reduced. This segmented approach maintains effective copper diffusion prevention while enabling thinner overall structure for smaller vias.
Solution Approach 2:
The barrier structure uses composite material composition with alternating barrier material layers and plasma treatment material layers. This composite structure combines the copper diffusion barrier properties of the barrier materials with the carbon cleaning properties of the plasma treatment layers, achieving both thin thickness and effective copper diffusion prevention.
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 multilayer barrier structure effectively reduces contact resistance and maintains electrical performance with a thinner profile compared to conventional barrier layers, addressing the challenge of smaller via sizes in advanced semiconductor devices.
Implementation Method 1
A first plasma treatment process is applied to the first barrier layer. A second plasma treatment process is applied to the second barrier layer.
Data Source
AI summary
A method for forming a multilayer barrier comprises forming a conductive line over a substrate, depositing a dielectric layer over the conductive line, forming a plug opening in the dielectric layer, forming a multilayer barrier through a plurality of deposition processes and corresponding plasma treatment processes.