Contact Via Barrier Layer Thickness Control
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Solution Overview
Problem
Existing contact via structures in integrated circuits face increased resistance due to barrier layer deposition at the bottom of through holes, which hinders efficient interconnection between upper and lower layers.
Innovation Solution
A method involving a roughening treatment of the buffer layer surface, followed by a reduced thickness barrier layer deposition using argon ion bombardment, and subsequent filling with a conductive material to reduce resistance, including steps like oxidation, hydrofluoric acid removal, and argon ion bombardment to weaken the bonding force between the barrier and buffer layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier layer is deposited in the through hole to prevent diffusion, then the reliability of the contact via is improved, but the resistance of the contact via increases
Solution Approach 1:
The patent applies different barrier layer thicknesses at different locations within the through hole. The barrier layer is thinner at the bottom of the through hole where it contacts the buffer layer, and thicker on the sidewalls. This local variation in thickness allows the barrier layer to prevent diffusion (maintaining reliability) while minimizing resistance by reducing the conductive path length at the critical bottom region.
Solution Approach 2:
The patent performs a roughening treatment on the buffer layer surface before depositing the barrier layer. This preliminary action creates a roughened surface that reduces the bonding force between the barrier layer and buffer layer, enabling the barrier layer to be deposited in a controlled manner with reduced thickness at the bottom, thereby lowering resistance while maintaining diffusion prevention capabilities.
2Object-affected harmful factors
If the barrier layer thickness is reduced to lower resistance, then the contact via resistance decreases, but the step coverage may be compromised
Solution Approach 1:
The patent implements non-uniform barrier layer thickness distribution, with thinner barrier layer at the bottom and thicker barrier layer on the sidewalls. This local quality variation ensures adequate step coverage and diffusion prevention on the sidewalls while minimizing resistance by reducing the barrier thickness at the bottom contact region.
Solution Approach 2:
The roughening treatment of the buffer layer surface is performed as a preliminary action before barrier layer deposition. This creates surface characteristics that enable controlled barrier layer formation with reduced thickness at the bottom, achieving both low resistance and adequate step coverage.
3Reliability
If the bonding force between barrier layer and buffer layer is strong, then the reliability is improved, but the barrier layer thickness cannot be reduced
Solution Approach 1:
The patent performs roughening treatment on the buffer layer surface as a preliminary action before barrier layer deposition. This creates a roughened surface that paradoxically reduces the bonding force between the barrier layer and buffer layer, enabling the barrier layer to be deposited with reduced thickness at the bottom while maintaining adequate adhesion for reliability.
Solution Approach 2:
The patent changes the surface parameters of the buffer layer through roughening treatment, altering the surface morphology and bonding characteristics. This parameter change enables the barrier layer to form with reduced thickness while maintaining the necessary adhesion for reliable contact via operation.
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 method effectively reduces the resistance of contact vias by thinning the barrier layer at the bottom of through holes while maintaining reliable step coverage and preventing damage to dielectric layers, enhancing the efficiency of interlayer connections.
Implementation Method 1
performing an oxidization process to the exposed surface of the buffer layer to form an oxidized layer
Implementation Method 2
removing the oxidized layer using a hydrofluoric acid solution
Implementation Method 3
performing an argon ion bombardment process to roughen the exposed surface of the buffer layer
Implementation Method 4
filling a conductive material into the through hole to form a contact via
Data Source
AI summary
In some embodiments, a contact via and a fabricating method thereof are provided. The method can comprise: providing a substrate; forming a buffer layer in the substrate; forming a dielectric layer covering the substrate and the buffer layer; forming a through hole in the dielectric layer, wherein a bottom of the through hole exposes a surface of the buffer layer; performing a roughening treatment to the exposed surface of the buffer layer to increase a roughness of the exposed surface of the buffer layer; forming a barrier layer in the through hole, and reducing a thickness of a portion of the barrier layer at the bottom of the through hole; and filling a conductive material into the through hole to form a contact via.