Guard Ring Trench Layout for Moisture and Crack Isolation
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Solution Overview
Problem
Existing semiconductor devices with guard rings face challenges in improving reliability, particularly in preventing moisture entry and managing cracks during the dicing process.
Innovation Solution
The semiconductor device incorporates a guard ring surrounded by a trench that penetrates the protective film and reaches inside the multilayer wiring structure, with the guard ring's bottom surface inclined to direct cracks away from the circuit formation region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a guard ring is formed to surround the circuit formation region, then moisture entry prevention is improved, but the structure becomes more complex and reliability is not sufficiently improved
Solution Approach 1:
The guard ring structure is segmented into multiple parts: the guard ring itself, the protective film covering it, and the trench surrounding it. This segmentation allows each component to perform its specific function - the guard ring blocks moisture, the protective film seals the interface, and the trench provides mechanical support and crack isolation - thereby improving overall reliability while maintaining moisture prevention
Solution Approach 2:
The patent implements a nested structure where the protective film is formed over the multilayer wiring structure and guard ring, and the trench is formed surrounding the guard ring and penetrating the protective film. This nested arrangement creates multiple layers of protection, where each layer reinforces the others, significantly improving reliability beyond what a single guard ring could achieve
2Reliability
If a trench is formed to surround the guard ring and penetrate the protective film, then crack propagation is prevented, but manufacturing complexity increases
Solution Approach 1:
The protective film is formed over the multilayer wiring structure and guard ring before the trench is formed. This preliminary action ensures that the protective film is already in place to seal the interface between the guard ring and the wiring structure, and the subsequent trench formation creates controlled openings that prevent crack propagation while maintaining the protective film's sealing function in covered areas
Solution Approach 2:
The protective film acts as an intermediary between the guard ring and the external environment. By forming the trench to penetrate this protective film rather than directly exposing the guard ring, the patent creates a controlled interface that prevents uncontrolled crack propagation while maintaining the protective film's role as a barrier, thus balancing reliability improvement with manufacturing feasibility
3Reliability
If the trench bottom surface is inclined to direct cracks away from the circuit formation region, then crack protection is improved, but manufacturing precision requirements increase
Solution Approach 1:
The trench bottom surface is formed with an asymmetric inclination rather than a flat or symmetric shape. This asymmetric design creates a directional guide for cracks, using the inclined surface to redirect crack propagation away from the circuit formation region toward the peripheral region. The asymmetry is intentionally designed to exploit crack propagation mechanics, turning the manufacturing challenge into a functional feature that improves reliability
Data Source
AI summary
A semiconductor device includes a semiconductor substrate, a multilayer wiring structure formed on the semiconductor substrate, a guard ring formed so as to surround a circuit formation region and penetrate the multilayer wiring structure, and a pad formed on the multilayer wiring structure. A protective film is formed so as to cover the multilayer wiring structure, the guard ring, and the pad. A trench is formed so as to penetrate the protective film and reach an inside of the multilayer wiring structure. The trench is formed so as to surround the guard ring. The guard ring includes a wiring formed on the multilayer wiring structure. The trench is spaced apart from and adjacent to the wiring. A bottom surface of the trench is inclined so as to be continuously deepened in a direction from the circuit formation region toward a peripheral region surrounding the circuit formation region.