SoC Shield Rings for EMI Isolation
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Solution Overview
Problem
System-on-chip (SoC) designs face significant challenges in addressing electromagnetic interference (EMI) and signal coupling, which impact both cost and time-to-market due to increasing transistor densities and high circuit frequencies.
Innovation Solution
A system-on-chip design incorporating EMI shield rings made of multi-layer metals and vias, grounded to protect analog/mixed-signal and memory blocks from interference, with serpentine signal lines passing through connection windows to minimize noise leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If transistor density is increased to integrate more functional blocks into a single SoC chip, then integration capability and functionality are improved, but electromagnetic interference and signal coupling between blocks worsen
Solution Approach 1:
The patent divides the SoC chip into distinct functional blocks (digital blocks, analog blocks, memory blocks) separated by shield rings. Each block is segmented and isolated from others using conductive shield structures that create electromagnetic barriers between adjacent functional areas, preventing interference while maintaining high integration.
Solution Approach 2:
The patent introduces shield rings as intermediary structures between functional blocks. These shield rings act as mediators that block electromagnetic fields from passing between adjacent blocks, using grounded conductive layers to absorb or redirect interference before it reaches sensitive circuits.
2Speed
If operating frequency is increased to improve processing speed, then performance is improved, but electromagnetic interference and signal coupling become more severe
Solution Approach 1:
The patent applies different shielding qualities to different regions of the chip based on their specific interference characteristics. High-speed digital blocks receive enhanced shielding compared to low-speed blocks, with shield ring density and conductivity optimized locally according to the interference risk and sensitivity of each functional area.
3Reliability
If shield rings are added to protect functional blocks from EMI, then electromagnetic interference protection is improved, but device complexity and manufacturing difficulty worsen
Solution Approach 1:
The patent designs shield rings that serve multiple functions: they act as EMI barriers, provide grounding paths, define block boundaries, and can be integrated with existing metal interconnect layers. This multi-functionality reduces the need for additional dedicated structures, simplifying the overall design despite the added protection capability.
Solution Approach 2:
The patent merges the shield ring structures with the existing metal interconnect layers and via structures of the semiconductor fabrication process. By combining EMI shielding functionality with the standard multi-layer metal stack already required for signal routing, the patent avoids adding separate dedicated shielding layers, thereby reducing manufacturing complexity.
4Reliability
If shield rings with multi-layer metals and vias are implemented, then EMI shielding effectiveness is improved, but manufacturing precision requirements worsen
Solution Approach 1:
The patent designs the shield ring structures to be formed using the same preliminary fabrication steps as the standard metal interconnect layers. By incorporating shield rings into the existing metal layer formation process sequence, the patent ensures that alignment and patterning are performed during the normal manufacturing flow, avoiding the need for additional precision-critical alignment steps.
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 shield ring structure effectively reduces electromagnetic interference, ensuring the SoC is immune to EMI and static electricity, thereby enhancing design efficiency and reducing product development costs and timelines.
Implementation Method 1
an EMI shield ring encircling the analog/mixed-signal integrated circuit for protecting the analog/mixed-signal integrated circuit from electromagnetic interference. The EMI shield ring is grounded and includes a metal rampart consisting of multi-layer metals and vias
Implementation Method 2
The EMI shield ring is grounded and includes a metal rampart consisting of multi-layer metals and vias. A pickup diffusion is connected to the metal rampart
Data Source
AI summary
A system-on-chip (SoC) that is immune to electromagnetic interference has block shield rings fabricated therein. The SoC includes a microprocessor core; an on-chip bus interface; an embedded memory block; and an analog/mixed-signal integrated circuit shielded by an EMI shield ring encircling the analog/mixed-signal integrated circuit for protecting the analog/mixed-signal integrated circuit from electromagnetic interference. The EMI shield ring is grounded and includes a metal rampart consisting of multi-layer metals and vias. A pickup diffusion is connected to the metal rampart. In one embodiment, the memory block is also shielded.