Selective Conductive Capping Layer for Via Interface Integrity
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Solution Overview
Problem
In modern integrated circuits, the formation of conductive vias often results in voids at the interface with conductive contact structures, leading to issues like copper migration and increased resistance due to the absence of a barrier layer under the vias.
Innovation Solution
The selective formation of a conductive capping layer, involving processes like selective deposition and annealing, ensures that the voids are filled, and a conductive via is formed with a conductive barrier layer and adhesion layer under the via, preventing copper migration and reducing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard via formation process is used, then the manufacturing process is simple, but voids form at the interface between the via and contact structure leading to copper migration and increased resistance
Solution Approach 1:
A conductive capping layer is formed on the contact structure before via formation. This preliminary action ensures that when the via is subsequently formed, the interface between the via and contact structure is already prepared with a conductive layer, preventing void formation and copper migration while maintaining manufacturing simplicity
Solution Approach 2:
The conductive capping layer acts as an intermediary between the contact structure and the via. This intermediate layer fills potential voids at the interface and provides a reliable conductive path, preventing copper migration and reducing resistance without significantly complicating the overall process
2Ease of manufacture
If no conductive capping layer is formed, then the manufacturing process is simpler, but copper migration occurs and resistance increases due to voids at the interface
Solution Approach 1:
The conductive capping layer is formed in advance on the contact structure before via deposition. This preliminary step ensures reliable electrical connections by preventing interface voids and copper migration, while the process remains manufacturable using standard semiconductor fabrication techniques
Solution Approach 2:
The formation of the conductive capping layer changes the physical and chemical parameters at the via-contact interface. By modifying the interface properties with a conductive layer, the reliability of the electrical connection is improved without requiring fundamental changes to the manufacturing process
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 method effectively fills voids at the interface, reducing the likelihood of copper migration and maintaining low resistance connections between conductive vias and contact structures.
Implementation Method 1
performing a selective deposition process to selectively form a layer of conductive material in the opening and on the conductive contact
Implementation Method 2
after selectively forming the layer of conductive material on the conductive contact, performing an anneal process
Data Source
AI summary
One illustrative method disclosed herein includes, among other things, forming an opening in a layer of insulating material so as to thereby expose at least a portion of a conductive contact, performing a selective deposition process to selectively form a layer of conductive material in the opening and on the conductive contact, performing an anneal process, depositing at least one conductive material above the selectively formed conductive material layer so as to over-fill the opening, and performing at least one planarization process so as to remove excess materials to thereby define a conductive via that is positioned in the opening and conductively coupled to the conductive contact.