Multilayer Electronic Component Solder Structure for Electrode Connectivity
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Solution Overview
Problem
The connectivity between internal and external electrodes in multilayer ceramic capacitors is compromised due to differences in shrinkage behaviors during the sintering process, leading to degraded electrical connectivity and moisture resistance reliability.
Innovation Solution
The implementation of Zn-based solder layers with Zn-Ni and Zn-Cu alloy layers at the interfaces between internal and external electrodes enhances the connectivity by forming stable alloy layers during the sintering process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If internal electrodes and dielectric layers are laminated and sintered to form a multilayer body, then high capacitance and small size are achieved, but connectivity between internal electrodes and external electrodes deteriorates due to differential shrinkage
Solution Approach 1:
A Zn-based solder layer is introduced as an intermediary between the internal electrode and the external electrode. This solder layer includes a Zn-Ni alloy sub-layer that bonds to the internal electrode and a Zn-Cu alloy sub-layer that bonds to the external electrode, mediating the connection and compensating for differential shrinkage during sintering.
Solution Approach 2:
The solder layer is constructed as a composite material with two distinct alloy compositions: a Zn-Ni alloy portion adjacent to the internal electrode and a Zn-Cu alloy portion adjacent to the external electrode. This composite structure allows each sub-layer to optimize its bonding characteristics for the specific interface it contacts.
2Strength
If the body is sintered to densify the structure, then mechanical strength is improved, but differential shrinkage between internal electrodes and dielectric layer causes connectivity deterioration
Solution Approach 1:
The invention changes the material parameter of the solder layer by using a Zn-based alloy with specific compositional ranges (Ni: 0.1-5 wt%, Cu: 0.1-5 wt%, Zn: balance). These parameter changes allow the solder layer to maintain bonding integrity during the sintering process and compensate for dimensional changes.
Solution Approach 2:
The Zn-based solder layer acts as a mediator between the internal electrode and external electrode, absorbing and compensating for the differential shrinkage that occurs during sintering. The solder layer's intermediate position allows it to accommodate dimensional changes while maintaining electrical connectivity.
3Ease of manufacture
If a simple Zn-based solder layer is used, then manufacturing complexity is reduced, but connectivity and moisture resistance reliability are insufficient
Solution Approach 1:
The solder layer is designed as a composite material with Zn-Ni and Zn-Cu alloy portions, where each component serves a specific function: Zn-Ni provides bonding to the internal electrode while Zn-Cu provides bonding to the external electrode and enhances moisture resistance. This composite approach improves reliability while maintaining manufacturing simplicity.
Solution Approach 2:
The solder layer exhibits local quality by having different alloy compositions at different locations: the Zn-Ni alloy portion is positioned adjacent to the internal electrode to optimize that interface, while the Zn-Cu alloy portion is positioned adjacent to the external electrode to optimize that interface and provide moisture barrier properties.
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
Improves electrical connectivity and moisture resistance reliability by stabilizing the connection between internal and external electrodes, reducing equivalent series resistance and maintaining structural integrity.
Implementation Method 1
the solder layer includes a first alloy layer disposed on an interfacial surface with the internal electrode and including Zn—Ni alloy, and a second alloy layer disposed on an interfacial surface with the external electrode and including Zn—Cu alloy
Implementation Method 2
sintering the sheets
Data Source
AI summary
A multilayer electronic component includes a body including a dielectric layer and internal electrodes disposed alternately with the dielectric layer, solder layers disposed on ends of the internal electrodes and each including a Zn-based solder, and external electrodes disposed on the solder layer, wherein the solder layer includes a first alloy layer disposed on an interfacial surface with the internal electrode and including Zn—Ni alloy, and a second alloy layer disposed on an interfacial surface with the external electrode and including Zn—Cu alloy.