Reinforced Galvanic Isolation Stack for Crack-Resistant High Voltage
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Solution Overview
Problem
Existing galvanic isolation devices face challenges in maintaining structural integrity and preventing dielectric breakdown, especially in high-voltage applications, due to the use of capacitive elements.
Innovation Solution
A reinforced galvanic isolation device is designed with alternating layers of high stress and low stress silicon dioxide between upper and lower metal coils, incorporating etch stop layers for precise etching and a thick plateau formation, enhancing resistance to cracking and providing a robust dielectric structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick plateau is formed between metal coils to improve voltage withstanding capability, then the resistance to dielectric breakdown is improved, but the plateau becomes more susceptible to cracking due to stress concentration
Solution Approach 1:
The thick plateau dielectric layer is segmented into multiple thinner dielectric sub-layers separated by conductive intermediate layers. This segmentation distributes the electrical stress across multiple interfaces and prevents stress concentration that would lead to cracking, while maintaining the overall thick plateau structure for high voltage withstanding capability
Solution Approach 2:
The plateau structure uses composite materials consisting of alternating dielectric layers and conductive layers. This composite structure combines the high voltage insulation properties of thick dielectric with the stress-distributing properties of conductive interlayers, resolving the contradiction between thickness for breakdown resistance and susceptibility to cracking
2Reliability
If capacitive elements are used for galvanic isolation to enable current blocking, then the isolation function is achieved, but dielectric breakdown becomes a key concern in high-voltage applications
Solution Approach 1:
The capacitive isolation function is segmented into multiple series-connected capacitive elements formed by alternating dielectric and conductive layers. This segmentation distributes the high voltage stress across multiple dielectric interfaces, reducing the electric field strength at any single interface and preventing dielectric breakdown while maintaining the galvanic isolation function
Solution Approach 2:
Conductive intermediate layers are inserted between dielectric layers to beforehand cushion and distribute electrical stress. These conductive layers act as stress-distributing elements that prevent localized electric field concentration that would lead to dielectric breakdown, providing protective cushioning before breakdown can occur
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 improves the structural integrity and resistance to dielectric breakdown, ensuring reliable operation in high-voltage environments by reinforcing the dielectric stack with alternating silicon dioxide layers and etch stop layers.
Implementation Method 1
The plateau also contains alternating layers of high stress and low stress silicon dioxide. The alternating layers of high stress silicon dioxide and low stress silicon dioxide provide a means of reinforcement of the plateau which improves resistance to cracking of the plateau.
Implementation Method 2
The upper etch stop layer provides an electrical signal during the plateau etch process which provides feedback on the amount of plateau which has been etched.
Data Source
AI summary
A microelectronic device including an isolation device. The isolation device includes a lower isolation element, an upper isolation element, and an inorganic dielectric plateau between the lower isolation element and the upper isolation element. The inorganic dielectric plateau contains an upper etch stop layer and a lower etch stop layer between the upper isolation element and the lower isolation element. The upper etch stop layer provides an end point signal during the plateau etch process which provides feedback on the amount of inorganic dielectric plateau which has been etched. The lower etch stop layer provides a traditional etch stop function to provide for a complete plateau etch and protection of an underlying metal bond pad. The inorganic dielectric plateau also contains alternating layers of high stress and low stress silicon dioxide, which provide a means of reinforcement of the inorganic dielectric plateau.