Conductive Via With Contact Flange Reducing Interconnect Resistance
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Solution Overview
Problem
Current dual damascene interconnect structures in semiconductor devices face challenges in achieving lower resistance and higher reliability for efficient signal transmission due to limitations in contact surface area and mechanical strength.
Innovation Solution
The implementation of a multilevel interconnect structure with a capping layer and dielectric layers, where an electrically conductive via with a contact flange is formed to increase the contact area between conductive features, reducing electrical resistance and enhancing mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional via structure is used in dual damascene interconnect, then the manufacturing process is simple, but the contact surface area is insufficient leading to higher electrical resistance
Solution Approach 1:
The patent applies dimensionality change by forming a contact flange that extends laterally from the via body, transforming a simple vertical via into a structure with both vertical and lateral dimensions. This flange extension increases the contact surface area with the conductive feature, thereby reducing electrical resistance without fundamentally changing the manufacturing process complexity
Solution Approach 2:
The patent employs preliminary action by forming the contact flange as an integral part of the via structure during the via formation process. The conductive material is deposited to form both the via body and the lateral flange in a single deposition step, ensuring proper contact geometry is established before subsequent processing steps
2Reliability
If the contact area between via and conductive feature is increased, then electrical resistance is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges the via formation and contact area expansion into a single integrated process step. The contact flange is formed as an extension of the via body using the same deposition and etching processes, eliminating the need for separate contact area formation steps and maintaining manufacturing simplicity
Solution Approach 2:
The contact flange structure serves multiple functions simultaneously: it provides electrical connection, reduces electrical resistance through increased contact area, and maintains mechanical alignment. This multi-functionality achieves resistance reduction without requiring additional specialized manufacturing steps
3Strength
If a larger contact area is created for the via, then mechanical strength is improved, but the via structure becomes more complex
Solution Approach 1:
The patent uses dimensionality change by extending the via structure laterally to form a contact flange. This lateral extension increases the contact area with the conductive feature, providing enhanced mechanical anchoring and strength without requiring additional structural elements or complex multi-component assemblies
Data Source
AI summary
An interconnect structure includes a first dielectric layer and a second dielectric layer each extending along a first axis to define a height and a second axis opposite the first axis to define a length. A capping layer is interposed between the first dielectric layer and the second dielectric layer. At least one electrically conductive feature is embedded in at least one of the first dielectric layer and the second dielectric layer. At least one electrically conductive via extends through the second dielectric layer and the capping layer. The via has an end that contacts the conductive feature. The end includes a flange having at least one portion extending laterally along the first axis to define a contact area between the via and the at least one conductive feature.