I/O Pad Cluster ESD Routing for Higher IC Density
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Solution Overview
Problem
Integrated circuits face challenges in providing effective Electrostatic Discharge (ESD) protection across both the wafer processing and packaging stages without compromising transistor density and area utilization.
Innovation Solution
The implementation of an integrated circuit design that includes clusters of contact pads with a first ESD protection line formed from a low-resistivity metal layer at the wafer processing stage, and a second ESD protection line formed from a redistribution metal layer during the packaging stage, which shorts out the first line to meet higher ESD protection standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ESD protection structures are implemented to protect integrated circuits during packaging stage, then ESD protection reliability is improved, but transistor density and area utilization deteriorate
Solution Approach 1:
The ESD protection structure is segmented into two distinct stages: a first ESD protection line formed during wafer processing stage, and a second ESD protection line formed during packaging stage. This segmentation allows each stage to have optimized protection measures without compromising the other, enabling high transistor density while maintaining reliable ESD protection.
Solution Approach 2:
The first ESD protection line is formed preliminarily during the wafer processing stage before packaging. This preliminary ESD protection structure provides baseline protection during wafer processing and serves as a foundation for the second ESD protection line that will be added during packaging stage.
2Reliability
If peripheral areas of the die are devoted to ESD ground rings, then ESD protection reliability is improved, but circuit density deteriorates
Solution Approach 1:
The ESD protection structure transitions from a two-dimensional ground ring configuration to a multi-layer three-dimensional structure with ESD protection lines formed in different metal layers and stages. This dimensional change allows ESD protection to coexist with high-density circuit布局 by utilizing vertical space rather than consuming peripheral horizontal area.
3Reliability
If contact pads are positioned closer to die edges, then ESD protection is improved, but area for transistor formation is reduced
Solution Approach 1:
The ESD protection approach is segmented into two stages with different requirements. During wafer processing stage, the first ESD protection line provides adequate protection with contact pads positioned optimally for circuit density. During packaging stage, the second ESD protection line enhances protection for handling operations, allowing contact pads to be positioned away from die edges to maximize transistor formation area.
4Device complexity
If a single ESD protection structure is designed for both wafer processing and packaging stages, then device complexity is reduced, but ESD protection reliability deteriorates
Solution Approach 1:
The ESD protection structure is made dynamic by implementing different protection levels for different processing stages. The first ESD protection line addresses wafer processing requirements, while the second ESD protection line addresses packaging stage requirements. This dynamic, stage-specific approach optimizes protection reliability for each stage without requiring an overly complex unified structure.
Data Source
AI summary
An integrated circuit package includes an integrated circuit die. The integrated circuit die includes core circuitry implemented in one or more layers of semiconductor material, a first cluster of first contact pads formed of a top metal layer of the integrated circuit die and coupled to the core circuitry, a second cluster of second contact pads formed of the top metal layer and coupled to the core circuitry, a first ESD protection line formed of the top metal layer extending between an area of the first cluster and an area of the second cluster, and ESD protection circuitry in the one or more layers of semiconductor material coupling each of the first contact pads and each of the second contact pads to the first ESD protection line by ESD protection circuitry. The integrated circuit package includes a passivation layer on the integrated circuit die and a second ESD protection line on the passivation layer formed of a redistribution metal layer and shorting a portion of the first ESD protection line.