Multilayered Capacitor Ni-P Pd-P Plated Electrodes
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Solution Overview
Problem
The use of tin-containing solder in multilayered capacitors leads to reliability issues at high temperatures, and conductive adhesives with epoxy and metallic fillers result in decreased bonding force with plated layers, causing mounting failures.
Innovation Solution
A multilayered capacitor design featuring external electrodes with an inner nickel-phosphorus plated layer and an outer palladium-phosphorus plated layer, formed through electroless plating, which enhances bonding force and prevents mounting failures even at high temperatures without using a tin layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If tin-containing solder is used in the plated layer, then ease of manufacture is improved, but reliability deteriorates at high temperatures (150°C or higher)
Solution Approach 1:
The patent applies composite materials by creating a multi-layer plated structure consisting of a Ni-P inner plated layer and a Pd-P outer plated layer. This composite structure replaces the traditional single-layer tin-plated structure, combining the advantages of different materials: nickel-phosphorus provides strong bonding with conductive adhesive and high temperature resistance, while palladium-phosphorus provides oxidation resistance and solderability, achieving both ease of manufacture and high reliability at temperatures of 150°C or higher.
2Ease of operation
If conductive adhesive is used as bonding material, then ease of operation is improved, but bonding force deteriorates when plated layer contains tin
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition of the plated layer from traditional tin-based to nickel-phosphorus and palladium-phosphorus composition. Specifically, the inner plated layer contains 0.01-10 wt% phosphorus and the outer plated layer contains 0.01-10 wt% phosphorus, creating a surface chemistry that is compatible with conductive adhesive. This compositional parameter change enables strong bonding force between the plated layer and conductive adhesive, maintaining ease of operation while eliminating the bonding force deterioration problem associated with tin-containing plated layers.
3Reliability
If nickel-phosphorus and palladium-phosphorus plated layers are used, then reliability is improved at high temperatures, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the plated layer into two distinct functional layers: an inner Ni-P plated layer and an outer Pd-P plated layer. Each layer is optimized for specific functions - the inner layer provides bonding strength and temperature resistance, while the outer layer provides oxidation resistance. This segmented structure achieves high reliability at temperatures of 150°C or higher while maintaining manufacturing simplicity through integration into the existing plated electrode formation process.
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 a decrease in bonding force between the conductive adhesive and the plated layer, ensuring reliable mounting of multilayered capacitors on substrates at temperatures of 150° C or higher without tin-related reliability issues.
Implementation Method 1
the inner plated layer may be formed by plating a first metal layer including nickel and phosphorus on the conductive layer by an electroless plating process, and the outer plated layer may be formed by plating a second metal layer including palladium and phosphorus on the inner plated layer by an electroless plating process
Data Source
AI summary
A multilayered capacitor includes a capacitor body including a plurality of dielectric layers and a plurality of internal electrodes; and external electrodes disposed on both end portions of the capacitor body and connected to exposed portions of the internal electrodes, respectively. Each of the external electrodes includes a conductive layer formed on the capacitor body and connected to the internal electrodes; an inner plated layer including nickel (Ni) and phosphorus (P), and covering the conductive layer; and an outer plated layer including palladium (Pd) and phosphorus (P), and covering the inner plated layer.