Manganese Oxide Layer on Copper Interconnects
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Solution Overview
Problem
In semiconductor device fabrication, copper interconnects face issues with barrier layer adhesion and reliability due to poor cohesion between copper and barrier layers, leading to potential short circuits and metal contamination, especially when forming manganese oxide layers is challenging.
Innovation Solution
A method involving the formation of a manganese oxide layer on copper interconnects using a gas containing an organic manganese compound and an oxidizing agent, followed by annealing to remove an anti-corrosion agent, ensuring selective deposition and improved adhesion with a subsequent barrier layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier layer is formed directly on copper interconnects, then copper diffusion into the insulation film is prevented, but adhesion between the barrier layer and copper interconnects is poor
Solution Approach 1:
A manganese oxide layer is introduced as an intermediate layer between the copper interconnect and the barrier layer. This intermediary layer improves adhesion between the copper and barrier layer while preventing copper diffusion into the insulation film, resolving the contradiction between adhesion and diffusion prevention.
Solution Approach 2:
The patent uses a composite structure consisting of copper interconnect, manganese oxide layer, and barrier layer. The manganese oxide layer serves as a transition material with properties that bridge copper and the barrier layer, achieving both good adhesion and effective diffusion prevention.
2Reliability
If CoWP or CoWB thin films are formed by electroless plating to improve adhesion, then cohesion between barrier layer and copper interconnects is improved, but high conductivity causes short circuit between interconnects
Solution Approach 1:
The patent replaces the conductive CoWP/CoWB thin films with a manganese oxide layer that has insulating properties. The manganese oxide layer provides the necessary adhesion improvement without creating short circuits, effectively substituting a problematic material with a suitable alternative.
3Reliability
If electroless plating is used to form thin films on copper interconnects, then adhesion is improved, but metal contamination and damage occur during cleaning of the substrate
Solution Approach 1:
The patent replaces electroless plating with atomic layer deposition (ALD) to form the manganese oxide layer. ALD provides excellent adhesion without the contamination and damage issues associated with electroless plating cleaning processes, offering a cleaner and more reliable alternative.
4Reliability
If a layer of organic anti-corrosion agent is formed on copper interconnects, then corrosion is prevented, but the layer must be removed by heating before forming manganese oxide
Solution Approach 1:
The anti-corrosion agent layer is applied in advance during CMP processing to protect copper interconnects during manufacturing. The layer is subsequently removed by heating before manganese oxide formation, ensuring corrosion protection during critical processing steps while allowing proper adhesion for the final barrier structure.
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 enhances the reliability of copper interconnects by suppressing electron migration and maintaining low resistance, while allowing for the formation of a stable manganese oxide layer without increasing interconnect resistance or leakage current.
Implementation Method 1
forming a thin layer including manganese oxide on the surface of the copper interconnect by supplying gas containing organic compound of manganese and gas containing an oxidizing agent to the substrate
Implementation Method 2
removing the layer of the anti-corrosion agent by heating the substrate
Data Source
AI summary
A method of fabricating a semiconductor device including a substrate having a copper interconnect exposed on a surface of an insulation film, wherein a layer of an anti-corrosion agent composed of organic material is formed on the surface of the copper interconnect. The method includes removing the layer of the anti-corrosion agent by heating the substrate; and forming a thin layer including manganese oxide on the surface of the copper interconnect by supplying a gas containing an organic compound of manganese to the substrate.