MLCC Ni-Plated Electrode Structure Against Ion Migration
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Solution Overview
Problem
Multilayer ceramic electronic components face issues with ion migration and cracking due to the use of Ag and Cu in thermosetting resin layers, which can lead to short circuits and mechanical failures under stress and thermal cycling.
Innovation Solution
A multilayer ceramic electronic component design featuring a Ni-plated layer with a stress of about −150 MPa or more and 50 MPa or less, applied to an electrically conductive resin layer, ensuring reliable contact with the component body and sealing the gap to prevent Ag precipitation and ion migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ag and Cu are used as metal powder in the thermosetting resin layer, then electrical conductivity is improved, but ion migration occurs causing short circuits
Solution Approach 1:
A Ni-plated layer is introduced as an intermediary barrier between the Ag/Cu-containing thermosetting resin layer and the external electrode. This Ni layer prevents direct contact and ion migration pathways while maintaining electrical conductivity through the resin layer, thus resolving the contradiction between conductivity and migration prevention.
Solution Approach 2:
The external electrode structure uses a composite configuration combining thermosetting resin with Ag/Cu metal powder for conductivity, overlaid with a Ni-plated layer for migration prevention. This composite structure allows each layer to perform its specific function: the resin provides flexibility and conductivity, while the Ni layer provides a protective barrier against ion migration.
2Strength
If epoxy-based thermosetting resin layer is provided between electrode layer and Ni-plated layer, then bending resistance is improved, but ion migration can still occur
Solution Approach 1:
The Ni-plated layer serves as an intermediary barrier that blocks ion migration pathways. It is positioned between the Ag/Cu-containing resin layer and the external electrode, preventing direct ion exchange while allowing the epoxy resin to provide its bending resistance function.
Solution Approach 2:
The external electrode combines multiple materials: epoxy resin for mechanical strength and bending resistance, Ag/Cu metal powder for electrical conductivity, and Ni-plating for ion migration prevention. This composite structure resolves the contradiction by assigning different functions to different materials within the same component.
3Reliability
If Ni-plated layer is applied with stress of about −150 MPa or more and 50 MPa or less, then contact with multilayer body is improved, but manufacturing precision is required
Solution Approach 1:
The stress state of the Ni-plated layer is controlled within a specific range (−150 MPa to 50 MPa) to ensure proper contact with the multilayer body. This parameter control allows the Ni layer to maintain reliable electrical contact and sealing without requiring extremely tight manufacturing tolerances, as the stress range provides a buffer zone for manufacturing variations.
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
This configuration effectively reduces ion migration and cracking, maintaining the mechanical strength and electrical integrity of the component while preventing short circuits.
Implementation Method 1
a stress is applied to the Ni-plated layer, the stress being about −150 MPa or more and about 50 MPa or less
Implementation Method 2
When a voltage is applied to the external electrode of the multilayer ceramic electronic component, Ag is ionized on the anode side and water is decomposed into ions
Implementation Method 3
water is decomposed into ions
Implementation Method 4
AgOH becomes silver oxide by decomposition
Implementation Method 5
migrates to the cathode side by becoming colloidal
Implementation Method 6
Ag is deposited by ionization of silver oxide
Implementation Method 7
transfer of electrons
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including ceramic layers and internal electrode layers laminated therein, a pair of external electrodes electrically connected to the internal electrode layers and provided on two end surfaces of the multilayer body. The pair of external electrodes each include a base electrode layer including a metal component, an electrically conductive resin layer on the base electrode layer and including a thermosetting resin and a metal component, and a Ni-plated layer on the electrically conductive layer. A stress of about −150 MPa or more and about 50 MPa or less is applied to the Ni-plated layer, and an end portion of the Ni-plated layer being in contact with the multilayer body.