Daisy-Chain Seal Ring Structure for Stacked Wafer Crack Prevention

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Solution Overview

Problem

Existing seal ring structures in semiconductor devices are inadequate in preventing wafer cracking during cutting or sawing, especially when semiconductor wafers are stacked and bonded together.

Innovation Solution

A daisy chain seal ring structure is introduced, comprising metal structures in both wafers and a metal bonding structure that couples these metal structures through their interface, forming a series of metal structures connected in a linear fashion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional seal ring structure is used, then the structure is simple, but it fails to prevent wafer cracking during cutting or sawing

Engineering Contradiction:

Improvewafer cracking preventionVSAvoidseal ring structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The seal ring structure is divided into multiple discrete metal structures arranged in a daisy-chain configuration. Each metal structure is separated from others, forming individual stress-relief units that collectively prevent wafer cracking during cutting or sawing operations while maintaining structural integrity.

Inventive Principle:

Principle #1Segmentation

2Productivity

If wafers are stacked and bonded together to form semiconductor devices, then device integration is achieved, but stress concentration at the interface causes wafer cracking

Engineering Contradiction:

Improvedevice integrationVSAvoidinterface stress resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The interface region is segmented into multiple discrete metal structures distributed across the bonding interface. These separated structures create stress-relief zones that prevent stress concentration, allowing wafers to be stacked and bonded together without causing wafer cracking at the interface during subsequent cutting or sawing.

Inventive Principle:

Principle #1Segmentation

3Reliability

If the seal ring structure is enhanced to prevent cracking, then reliability improves, but manufacturing complexity increases

Engineering Contradiction:

Improveseal ring effectivenessVSAvoidseal ring fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The seal ring is fabricated as multiple separate metal structures that can be independently formed and positioned. This segmentation allows each structure to be manufactured using standard semiconductor fabrication processes, and they are subsequently connected through the bonding interface, achieving enhanced cracking prevention without requiring complex monolithic seal ring fabrication.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250062166A1Daisy-chain seal ring structure

Publication Date: 2025.02.20 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor device includes a first wafer and a second wafer. The semiconductor device includes a seal ring structure comprising a first metal structure in a body of the first wafer, a second metal structure in the body of the first wafer, a third metal structure in a body of the second wafer, and a metal bonding structure including a first set of metal elements coupling the first metal structure and the third metal structure through an interface between the first wafer and the second wafer, and a second set of metal elements coupling the second metal structure and the third metal structure through the interface between the first wafer and the second wafer.