Stacked-Die Seal Ring Structure for Leakage and Crack Isolation
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Solution Overview
Problem
Stacked-die structures face issues with crack propagation during dicing and moisture penetration, particularly when IC dies have different operating voltages, leading to shorting and electrical leakage, which conventional seal ring structures with diodes are ineffective in addressing.
Innovation Solution
A seal ring structure incorporating an interconnect structure, such as a backside through silicon via, electrically isolates well structures and provides a physical barrier, eliminating the need for diodes and reducing moisture and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional seal ring structures with diodes are used, then moisture penetration is addressed, but electrical leakage and shorting occur when IC dies have different operating voltages
Solution Approach 1:
The patent removes the diode component from the seal ring structure entirely. Instead of using a diode-based seal ring that causes electrical leakage between IC dies with different operating voltages, the invention extracts this harmful element and replaces it with a passive seal ring structure that provides only the sealing function without electrical conduction paths.
Solution Approach 2:
The patent introduces an intermediary material layer between the IC dies that serves as both a seal and an electrical isolator. This intermediary structure prevents moisture penetration while also blocking electrical leakage paths, resolving the contradiction between sealing effectiveness and electrical isolation.
2Strength
If seal ring structures are added to prevent crack propagation, then structural integrity improves, but device complexity increases
Solution Approach 1:
The patent merges the seal ring structure with the existing bonding interface between IC dies. By integrating the sealing function into the bonding process and using the same structural elements for both mechanical bonding and moisture sealing, the invention provides crack resistance without significantly increasing device complexity.
Solution Approach 2:
The seal ring structure is designed to serve multiple functions simultaneously: it provides moisture sealing, crack propagation prevention, and electrical isolation. This multi-functionality reduces the need for separate components, thereby maintaining structural simplicity while achieving multiple protective goals.
3Reliability
If diodes are included in seal ring structures to address electrical isolation, then electrical leakage is reduced, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the diode component from the seal ring structure, eliminating the need for additional semiconductor fabrication steps to create and integrate diodes. This simplification maintains electrical isolation functionality while significantly reducing manufacturing complexity and cost.
Solution Approach 2:
The patent replaces expensive and complex diode structures with a simpler, more cost-effective seal ring structure that achieves the necessary electrical isolation through material selection and geometric design rather than active electronic components.
Data Source
AI summary
Some implementations described herein provide techniques and apparatuses for a stacked-die structure including a first integrated circuit device over a second integrated circuit device, where an operating voltage of the first integrated circuit device is different relative to an operating voltage of the second integrated circuit device. The first integrated circuit device includes a first portion of a seal ring structure of the stacked-die structure. The first portion includes an interconnect structure that connects a backside redistribution layer of the first integrated circuit device with first metal layers of the first integrated circuit device. The seal ring structure including the interconnect structure eliminates the use of diodes and electrically isolates well structures of the first integrated circuit device to reduce leakage paths relative to a stacked-die structure having a seal ring structure including a diode within the stacked-die structure. Furthermore, use of the interconnect structure as part of the seal ring structure substantially eliminates moisture and/or cracking from penetrating the stacked-die structure.