Z-Shaped Notch Seal Ring for IC Moisture and Noise Isolation

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Solution Overview

Problem

Conventional seal rings in integrated circuits (ICs) are vulnerable to moisture and ionic contaminants entering through slits, which can lead to reliability issues due to potential water, moisture, or crack penetration.

Innovation Solution

A Z-shaped notch is incorporated into the seal rings, elongating the penetration path and blocking the entry of water, moisture, or cracks, while also preventing noise coupling between circuits by cutting the seal ring into portions that break potential paths for noise induction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional seal ring is formed around the chip periphery, then structural reinforcement is provided, but moisture and ionic contaminants can penetrate through slits causing reliability issues

Engineering Contradiction:

Improveoperational reliabilityVSAvoidmoisture and ionic contaminant penetration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The seal ring is segmented by introducing notches that divide the continuous ring into discrete sections. This segmentation prevents the formation of continuous conductive paths for moisture and ionic contaminants while maintaining the structural reinforcement function of the seal ring.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The notch configuration extends the penetration path from a straight linear path to a multi-dimensional tortuous path through the seal ring thickness. This dimensional transformation effectively blocks contaminant ingress by requiring contaminants to navigate a complex three-dimensional path rather than a direct route.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Strength

If a seal ring is formed to protect chip periphery, then structural reinforcement is achieved, but noise coupling between circuits can occur through the continuous metal band

Engineering Contradiction:

Improvestructural reinforcementVSAvoidnoise coupling

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The continuous seal ring is divided into separate segments by notches, which interrupts the electromagnetic coupling path between different circuit regions. This segmentation maintains the mechanical strength of the seal ring while eliminating the noise coupling pathway that would exist in a continuous metal band.

Inventive Principle:

Principle #1Segmentation

3Reliability

If a straight slit is introduced in the seal ring, then the seal ring is cut to prevent current induction, but water, moisture, or cracks can penetrate through the direct path

Engineering Contradiction:

Improveprotection from current inductionVSAvoidwater, moisture, or crack penetration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The notch geometry transforms the simple linear slit into a curved, tortuous path through the seal ring. This curvature increases the effective length and complexity of the penetration path, making it difficult for water, moisture, and cracks to follow a direct route through the seal ring while still achieving the electrical isolation function.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS7602065B2Seal ring in semiconductor device

Publication Date: 2009.10.13 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor device includes a first circuit, a first seal ring and at least one first notch. The first seal ring surrounds the first circuit. The first notch cuts the first seal ring. Specifically, the first notch includes an inner opening, an outer opening and a connecting groove. The inner opening is located on the inner side of the first seal ring. The outer opening is located on the outer side of the first seal ring. The outer opening and the inner opening are not aligned. The connecting groove connects the inner opening and the outer opening.