Multilayer Varistor Structure for ESD Stability and Migration Control
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Solution Overview
Problem
Multilayer varistors experience deterioration in electrical characteristics due to electrostatic discharge (ESD), leading to reduced ESD resistance and potential migration issues.
Innovation Solution
A multilayer varistor design featuring a sintered compact with internal and external electrodes, and a high-resistivity layer that includes a thinner region with a smaller thickness than surrounding regions, facilitating oxygen supply and reducing plating deposition, thereby enhancing ESD resistance and electrode firmness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-resistivity layer with uniform thickness is used to cover the sintered compact, then electrical insulation is improved, but electrical characteristics deteriorate after electrostatic discharge (ESD)
Solution Approach 1:
The high-resistivity layer is designed with non-uniform thickness, featuring a thinner region (5-20 μm) at the center and thicker regions (20-50 μm) at the edges. This local variation in thickness allows the center to better withstand ESD while maintaining overall insulation performance through the thicker peripheral regions.
2Object-affected harmful factors
If the high-resistivity layer thickness is increased to improve insulation, then electrical insulation is improved, but oxygen supply to the sintered compact is restricted, leading to migration issues
Solution Approach 1:
The high-resistivity layer exhibits spatially varying thickness with a thinner central region (5-20 μm) that allows oxygen penetration to prevent migration, and thicker peripheral regions (20-50 μm) that provide electrical insulation. This local differentiation resolves the contradiction between insulation and oxygen supply requirements.
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 design effectively reduces electrical characteristic deterioration and increases ESD resistance while minimizing migration and improving electrode installation, maintaining consistent oxygen partial pressure and surface roughness.
Implementation Method 1
The high-resistivity layer includes a thinner region having a smaller thickness than a surrounding region that surrounds the thinner region, thereby effectively reducing deterioration in electrical characteristics due to the ESD
Implementation Method 2
a high-resistivity layer arranged to cover the sintered compact at least partially
Data Source
AI summary
A multilayer varistor according to the present disclosure includes; a sintered compact; an internal electrode provided inside the sintered compact; a high-resistivity layer arranged to cover the sintered compact at least partially; and an external electrode arranged to cover the high-resistivity layer partially and electrically connected to the internal electrode. The high-resistivity layer includes a thinner region having a smaller thickness than a surrounding region that surrounds the thinner region.