IC Shield and Pad Layer Structure for Secure High-I/O Memory
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Solution Overview
Problem
The increasing number of I/O terminals on high-performance computing and AI chips makes it challenging to simultaneously fabricate a shield layer and bonding pads on a single aluminum metal layer, compromising security and functionality.
Innovation Solution
An integrated circuit structure is developed with a copper interconnect structure, an aluminum pad layer, a passivation layer, and an aluminum shield layer that is electrically connected to the copper layer through tungsten vias, allowing for separate fabrication and enhanced security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single aluminum metal layer is used for both bonding pads and shield layer, then fabrication process is simplified, but security protection is compromised due to inability to simultaneously fabricate both structures
Solution Approach 1:
The patent divides the aluminum metal layer into two separate layers: an aluminum pad layer for bonding pads and an aluminum shield layer for security protection. This segmentation allows each layer to be independently fabricated and optimized for its specific function, resolving the contradiction between fabrication simplicity and security protection.
Solution Approach 2:
The patent introduces a vertical dimension by stacking the aluminum pad layer and aluminum shield layer at different heights. The aluminum shield layer is positioned between the copper interconnect structure and the aluminum pad layer, creating a multi-layer security architecture that enables simultaneous fabrication of both bonding pads and shield structures.
2Productivity
If the number of I/O terminals is increased to increase bandwidth, then computing performance is improved, but fabrication complexity increases making it difficult to simultaneously fabricate shield layer and bonding pads
Solution Approach 1:
By segmenting the aluminum layer into separate pad and shield layers, the patent enables independent fabrication processes for each function. This allows the bonding pads to accommodate increased I/O terminals for higher bandwidth while the shield layer maintains its security function without interfering with the pad fabrication process.
Solution Approach 2:
The patent introduces a dielectric layer as an intermediary between the aluminum shield layer and aluminum pad layer. This intermediary structure facilitates the coexistence of both layers, allowing high-density bonding pads to be fabricated alongside the shield layer without increasing overall fabrication complexity.
3Productivity
If bonding pads are made larger to accommodate more I/O terminals, then bandwidth is increased, but area available for shield layer is reduced
Solution Approach 1:
The patent resolves the area conflict by transitioning to a three-dimensional multi-layer architecture. The aluminum shield layer and aluminum pad layer are positioned at different vertical levels, allowing both structures to coexist without competing for the same planar area. This enables large bonding pads for high bandwidth while maintaining adequate shield layer coverage for security protection.
Data Source
AI summary
An integrated circuit structure includes an aluminum pad layer on a dielectric stack, a passivation layer covering the aluminum pad layer, and an aluminum shield layer including aluminum routing patterns disposed directly above an embedded memory area and embedded in the dielectric stack. The aluminum shield layer is electrically connected to the uppermost copper layer through a plurality of tungsten vias. The plurality of tungsten vias is embedded in the dielectric stack.