Multilayer Ceramic Capacitor Sn Plating Solder Bursting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multilayer ceramic capacitors with thermosetting resin outer electrodes face issues with solder bursting due to moisture absorption and decomposition during high-temperature soldering, leading to defects such as chip detachment and reduced reliability in severe environments.
Innovation Solution
The capacitors incorporate a Sn plating layer directly on the resin electrode layer, allowing for gas release paths and reducing the need for a Ni plating layer, which helps in preventing solder bursting by controlling the Lf/La ratio and maintaining a strong fixing force with the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thermosetting resin layer is used for outer electrodes to prevent cracks in severe environments, then crack resistance is improved, but moisture absorption increases and solder bursting occurs
Solution Approach 1:
The outer electrode is segmented into multiple functional layers: a resin electrode layer containing thermosetting resin for crack resistance, a Ni plating layer for moisture barrier and adhesion, and a Sn plating layer for soldering. Each layer addresses specific requirements without compromising overall reliability.
Solution Approach 2:
The outer electrode uses a composite structure combining organic thermosetting resin with inorganic metal plating layers. This composite approach leverages the crack-resistant properties of the resin while the metal layers provide moisture barrier and soldering functionality, resolving the contradiction between mechanical strength and reliability.
2Reliability
If a Ni plating layer is added to prevent solder bursting, then sealing properties are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The Ni plating layer serves multiple functions simultaneously: it acts as a moisture barrier to prevent solder bursting, provides adhesion between the resin layer and Sn plating layer, and enables proper soldering. This multi-functionality justifies the additional layer by consolidating multiple requirements into a single component.
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 solder bursting and ensures a strong fixing force between the substrate and the capacitor, enhancing reliability and cost-effectiveness by eliminating the need for a Ni plating layer.
Implementation Method 1
moisture adsorbed to a resin in the resin electrode layer and resin-decomposed components are vaporized by heating performed when a multilayer ceramic capacitor is mounted on a substrate by reflow soldering
Implementation Method 2
the multilayer ceramic capacitor containing such a thermosetting resin tends to adsorb moisture because the thermosetting resin itself has hygroscopicity
Implementation Method 3
such a resin is decomposed when exposed to a high temperature of about 250° C. in lead-free soldering (LF soldering)
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including dielectric layers, inner electrodes and outer electrodes that are connected to the inner electrodes and disposed on a first end surface and a second end surface of the multilayer body. The outer electrodes each include a resin electrode layer containing a thermosetting resin and a metal component and a plating layer in contact with the resin electrode layer. The metal component of the resin electrode layer contains Ni. The plating layer is a Sn plating layer.