IC Interconnect Structure With Segmented Aluminum Shield and Pads
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Solution Overview
Problem
The increasing number of I/O terminals on high-performance computing and AI chips makes it difficult to simultaneously fabricate a shield layer and bonding pads on a single aluminum metal layer, compromising the security of IC chips.
Innovation Solution
An integrated circuit structure with a copper interconnect structure, an aluminum pad layer, and an aluminum shield layer electrically connected through a tungsten via, where the aluminum shield layer is positioned between the uppermost copper layer and the aluminum pad layer, and a passivation layer partially covers the aluminum pad and dielectric layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single aluminum metal layer is used for both shield layer and bonding pads, then fabrication process is simple, but it becomes difficult to fabricate when the number of I/O terminals increases significantly
Solution Approach 1:
The patent divides the originally single aluminum metal layer into two separate layers: a first aluminum metal layer for the shield layer and a second aluminum metal layer for the bonding pads. This segmentation allows each layer to be independently fabricated and optimized, resolving the conflict between process simplicity and fabrication feasibility when I/O terminals increase significantly.
2Productivity
If the number of I/O terminals is increased to increase bandwidth, then performance is improved, but it becomes difficult to simultaneously fabricate shield layer and bonding pads
Solution Approach 1:
By segmenting the aluminum metal layers into separate shield layer and bonding pad layer, the patent enables independent fabrication processes for each function. This allows the bonding pad area to be expanded to accommodate increased I/O terminals for higher bandwidth while maintaining the shield layer's security function without fabrication conflicts.
3Reliability
If shield layer is provided to protect IC chip, then security is improved, but fabrication becomes difficult with increased I/O terminals
Solution Approach 1:
The patent maintains the shield layer's security function by providing a dedicated first aluminum metal layer for shielding, while separately providing a second aluminum metal layer for bonding pads. This segmentation ensures that the shield layer's security reliability is preserved even when the bonding pad structure becomes complex due to increased I/O terminals.
Solution Approach 2:
The patent introduces a dielectric layer as an intermediary between the first aluminum metal layer (shield) and the second aluminum metal layer (bonding pads). This dielectric layer enables the coexistence of both functions by providing electrical isolation and structural separation, making fabrication feasible while maintaining security.
Data Source
AI summary
An integrated circuit structure includes a substrate with a circuit region thereon and a copper interconnect structure disposed on the substrate. The copper interconnect structure includes an uppermost copper layer covered by a dielectric layer. An aluminum pad layer is provided on the dielectric layer. A metal layer is provided on the circuit region and is located between the uppermost copper layer and the aluminum pad layer.