Guard Ring Trench Capping for Crack Propagation
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Solution Overview
Problem
Existing semiconductor fabrication techniques fail to prevent crack propagation into active circuitry due to mechanical and thermal stresses, leading to reliability failures during wafer dicing and accelerated testing, as hermetic seals are breached by moisture penetration.
Innovation Solution
A trench is patterned in a polyimide layer over a guard ring with a capping layer deposited on the etched passivation layer, forming a strong mechanical interface with the top metal layer to prevent crack propagation, and additional embodiments involve depositing metal and polyimide layers to enhance the interface strength and prevent crack initiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the guard ring structure is extended to prevent moisture penetration, then hermetic seal integrity is improved, but the device complexity increases
Solution Approach 1:
The patent segments the guard ring structure into distinct functional components: the metal guard ring layers, the deep trenches, the nitride passivation layers, and the oxide passivation layers. Each segment performs a specific function - the metal layers provide structural framework and electrical connectivity, the trenches create physical barriers, and the passivation layers provide chemical protection. This segmentation allows for modular fabrication and simplifies the overall manufacturing process despite the enhanced protective functionality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents crack propagation and reliability failures by creating a strong mechanical interface between the passivation and top metal layers, enhancing the guard ring design to withstand thermal and mechanical stresses.
Implementation Method 1
The capping layer and the top metal layer form a mechanical strong interface to prevent a crack propagation
Data Source
AI summary
An embodiment of the present invention is a technique to prevent reliability failures in semiconductor devices. A trench is patterned in a polyimide layer over a guard ring having a top metal layer. A passivation layer is etched at bottom of the trench. A capping layer is deposited on the trench over the etched passivation layer. The capping layer and the top metal layer form a mechanical strong interface to prevent a crack propagation.