Graphene Interconnect Structure for Misalignment-Tolerant Contacts
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Solution Overview
Problem
Inadvertent misalignments between conductive features in interconnect structures of integrated circuits lead to increased contact resistance and the risk of short circuits, particularly problematic as technology nodes shrink, affecting device reliability and performance.
Innovation Solution
A graphene layer is formed over conductive features to reduce contact resistance and a selective etch-stop layer is used for proper insulation between conductive features, even when misaligned, ensuring reliable interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conductive features are scaled down to smaller technology nodes, then production efficiency increases and costs decrease, but contact resistance increases due to misalignment between via features and metal line features
Solution Approach 1:
An etch-stop layer is formed over the first conductive feature before the via feature is formed. This preliminary layer ensures that even if misalignment occurs during subsequent processing, the etch-stop layer prevents the via feature from directly contacting adjacent conductive features, thereby preventing short circuits while maintaining the benefits of scaled-down technology nodes
Solution Approach 2:
The etch-stop layer acts as an intermediary element between the via feature and the first conductive feature. This intermediate layer provides a safety margin that accommodates misalignment without causing electrical shorts, thus resolving the contradiction between maintaining small feature sizes for productivity and preventing contact resistance issues for reliability
2Manufacturing precision
If conductive features are scaled down, then geometry size decreases and functional density increases, but the risk of short circuits between uninsulated conductive features increases
Solution Approach 1:
The etch-stop layer is formed in advance over the conductive features before the via holes are etched. This preliminary protective layer ensures that even with reduced geometry sizes and tighter spacing, the via features cannot directly short adjacent conductive features, thus enabling continued scaling while mitigating short circuit risks
Solution Approach 2:
The etch-stop layer provides a protective cushion or safety margin before the via feature can reach the conductive feature. This beforehand protection allows the design to tolerate misalignment and maintains insulation between conductive features even at smaller geometry sizes where misalignment has greater impact
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 graphene layer reduces contact resistance and the selective etch-stop layer prevents short circuits, enhancing device reliability and performance by maintaining proper insulation during misalignment.
Implementation Method 1
Graphene-assisted low-resistance interconnect structures and methods of formation thereof
Implementation Method 2
a selective etch-stop layer is used for proper insulation between conductive features
Data Source
AI summary
A semiconductor structure is provided. The semiconductor structure includes a first conductive feature and a second conductive feature disposed in an interlayer dielectric (ILD) layer. The semiconductor structure includes a first graphene layer disposed over the first conductive feature and a second graphene layer disposed over a portion of the second conductive feature. An etch-stop layer (ESL) is horizontally interposed between the first graphene layer and the second graphene layer. A side surface of the first or the second graphene layer directly contacts a side surface of the ESL. A third conductive feature is electrically coupled to the second conductive feature. The third conductive feature is separated from the first graphene layer by a portion of the ESL, and the third conductive feature also directly contacts a top surface of the ESL.