Laminated Electronic Component Plating Film Structure
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Solution Overview
Problem
Existing methods for forming external terminal electrodes in laminated electronic components, such as electroless plating, suffer from issues like peeling between layers, low deposition rate, and insufficient plating growth, while electrolytic plating has inferior throwing power, leading to inadequate connectivity and increased volume requirements.
Innovation Solution
A laminated electronic component with a plating film structure comprising multiple layers, where the first layer is formed by electroless plating and subsequent layers by electrolytic plating, achieving a total thickness of 3 μm to 15 μm with a grain size of 0.5 μm or more, enhancing adhesion and bonding while increasing productivity and reducing oxidation susceptibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electroless plating is used to form the first plating layer, then the plating layer has small crystal grain sizes and is susceptible to oxidation, but peeling occurs between plating layers and productivity is reduced
Solution Approach 1:
The plating structure is divided into multiple layers with different functions: a first plating layer (Cu, Ni, or Pd) formed by electroless plating for adhesion and throwing power, and a second plating layer (Sn, Pb, or Zn) formed by electrolytic plating for solderability and oxidation resistance. This segmentation allows each layer to be optimized for its specific function, resolving the contradiction between adhesion and productivity.
Solution Approach 2:
The external terminal electrode uses a composite plating structure combining different materials (Cu/Ni/Pd + Sn/Pb/Zn) with different properties. The base layer provides adhesion and plating growth capability, while the outer layer provides solderability and oxidation resistance, achieving both reliability and productivity goals.
2Reliability
If the paste electrode layer thickness is increased to ensure electrical connection, then solderability is improved, but the effective volume for capacitance is reduced
Solution Approach 1:
The paste electrode layer is extracted and replaced with a plating-based electrical connection structure. The plating layers (total thickness 3-15 μm) provide both electrical connection and solderability without requiring the thick paste layers (several tens to hundreds of μm), thereby preserving effective capacitance volume while maintaining reliability.
Solution Approach 2:
The thickness parameter of the terminal electrode structure is changed from paste layers (tens-hundreds of μm) to plating layers (3-15 μm total). This parameter change achieves the same electrical connection function with much smaller volume, resolving the contradiction between connection reliability and capacitance volume.
3Productivity
If electrolytic plating is used to increase deposition rate, then productivity is improved, but plating growth is insufficient and connectivity is inadequate
Solution Approach 1:
The electroless plating layer is formed first as a preliminary step to ensure uniform plating growth and adequate connectivity. This preliminary layer provides a foundation that enables subsequent electrolytic plating to achieve both high deposition rate and uniform growth, resolving the contradiction between productivity and manufacturing precision.
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 improves the adhesion and bonding strength between plating layers, increases the grain size of metal grains, and enhances the density and solderability of the external terminal electrodes, addressing the limitations of existing methods and increasing productivity.
Implementation Method 1
a method of forming an external terminal electrode by depositing a conductive metal film via electroless plating onto the entire sidewall surface of a laminate at which internal electrodes are exposed
Implementation Method 2
subsequent layers by electrolytic plating
Data Source
AI summary
A laminated electronic component includes a first plating film that defines a base for external terminal electrodes and that includes a plurality of layers including a first layer made of, for example, copper and a second layer provided on the first layer. The total thickness of the first plating film is about 3 μm to about 15 μm, and the thickness of the second layer is about 2 to 10 times as thick as the thickness of the first layer. The first layer is formed by electroless plating, and the second layer is formed by electrolytic plating. This formation results in a grain size of about 0.5 μm or more of a metal grain included in the second layer, and thus makes the film less susceptible to oxidation.