Multilayer Ceramic Capacitor Plating for Low-Profile Adhesion
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Solution Overview
Problem
Multilayer ceramic capacitors with low profile designs face challenges in achieving adequate adhesion strength between the lower electrode and the metal plating layer, which affects their reliability and mounting performance, especially in miniaturized and thinned configurations.
Innovation Solution
The design incorporates sintered electrodes made of nickel with sequentially stacked plating layers, including a first plating layer of nickel and a second plating layer of copper or tin, which extend to the body's surfaces to enhance adhesion and reliability, while maintaining a specific thickness ratio to ensure strong bonding and moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the capacitor is miniaturized and thinned to reduce mounting area, then the mounting area is reduced, but the adhesion strength between the lower electrode and metal plating layer deteriorates
Solution Approach 1:
The patent applies composite materials by using a multi-layer plating structure consisting of a first plating layer (Ni-P alloy) and a second plating layer (Cu, Sn, or Zn) on the lower electrode. This composite plating structure provides both strong adhesion to the electrode and excellent solderability, resolving the contradiction between miniaturization and adhesion strength.
Solution Approach 2:
The patent changes the chemical composition parameters of the plating layers by specifying that the first plating layer contains Ni-P alloy with specific phosphorus content (3-10 at%), and the second plating layer contains specific metals (Cu, Sn, or Zn) with controlled thickness ratios. These parameter changes optimize both adhesion and mounting properties in miniaturized capacitors.
2Area of stationary object
If the capacitor is miniaturized and thinned, then the mounting area is reduced, but the reliability of the capacitor deteriorates
Solution Approach 1:
The multi-layer plating structure with Ni-P alloy as the first layer and Cu/Sn/Zn as the second layer provides both strong adhesion and excellent reliability. The Ni-P alloy layer offers superior corrosion resistance and bonding strength, while the second layer provides solderability and moisture barrier properties, ensuring high reliability in miniaturized capacitors.
Solution Approach 2:
The patent applies beforehand cushioning by incorporating a Ni-P alloy plating layer that provides corrosion resistance and adhesion strength before the capacitor is subjected to mounting stresses and environmental conditions. This pre-established protective layer prevents future failures from peeling, cracking, or corrosion.
3Ease of manufacture
If a simple single-layer plating is used, then the manufacturing process is simplified, but the adhesion strength and moisture resistance are insufficient
Solution Approach 1:
The patent uses composite materials with a two-layer plating structure where the first layer (Ni-P alloy) provides adhesion and corrosion resistance, and the second layer (Cu, Sn, or Zn) provides solderability and moisture barrier. This composite approach achieves superior adhesion strength and moisture resistance while maintaining reasonable manufacturing complexity through established plating processes.
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 significantly improves the adhesion strength and reliability of the multilayer ceramic capacitors, preventing peeling and cracking, and enhances their performance in miniaturized and thinned forms, suitable for embedded and surface-mount applications.
Implementation Method 1
a first plating layer and a second plating layer which are sequentially stacked on the sintered electrodes, and extend to and are formed on third and fourth surfaces of the body, respectively
Data Source
AI summary
A multilayer ceramic capacitor includes a body including a dielectric layer, and first and second internal electrodes with the dielectric layer interposed therebetween, and a first through-electrode passing through the body and connected to the first internal electrode; a second through-electrode passing through the body and connected to the second internal electrode; first and second external electrodes formed on the first and second surfaces and connected to the first through-electrode; and third and fourth external electrodes spaced apart from the first and second external electrodes and connected to the second through-electrode, wherein the first to fourth external electrodes are sintered electrodes including nickel, and each comprises a first plating layer and a second plating layer sequentially stacked on the sintered electrodes.