Laminated Ceramic Component Plating Layer Adhesion
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Solution Overview
Problem
The existing methods for manufacturing laminated ceramic electronic components face challenges in maintaining bonding strength and adhesion force between plating layers and the component main body, especially when heat treatment at temperatures of 1000° C or more leads to partial melting of copper plating layers, reducing bonding strength and solderability.
Innovation Solution
A method involving a controlled heat treatment at 1000° C or more with an average temperature increase rate of 100° C/min or more is used to form a plating layer with a surface area ratio of 1.01 or more, preventing melting and enhancing adhesion, and an interdiffusion region extending 2 μm or more from the internal electrode surfaces, ensuring bonding strength and solderability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heat treatment is performed at 1000°C or more to improve bonding strength, then bonding strength between plating layer and component main body is improved, but copper plating layer partially melts causing adhesion force to decrease
Solution Approach 1:
A nickel undercoat layer is formed on the copper plating layer before heat treatment. This nickel layer acts as a protective barrier that prevents the copper from oxidizing and melting during the subsequent heat treatment at 1000°C or higher, thereby maintaining both bonding strength and adhesion force
Solution Approach 2:
The plating structure uses a composite of multiple metal layers (copper base layer, nickel intermediate layer, and outer plating layer). This composite structure combines the high bonding strength of copper with the high melting point and oxidation resistance of nickel, resolving the contradiction between achieving strong bonding and preventing melting
2Reliability
If paste electrode layers are used to ensure electrical connection, then electrical connectivity is achieved, but component volume increases due to thick paste layers
Solution Approach 1:
The invention extracts and eliminates the thick paste electrode layers from the component structure. Instead, thin plating layers (several micrometers thick) are used to form external terminal electrodes that provide both electrical connectivity and solderability without requiring additional volume
Solution Approach 2:
The invention changes the dimensional parameter of the electrode layers from thick (several tens to hundreds of micrometers for paste) to thin (several micrometers for plating). This parameter change maintains electrical functionality while dramatically reducing the volume occupied by electrode structures
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 approach maintains the bonding strength and adhesion force between the plating layer and the component main body, preventing melting and ensuring effective electrical connections and solderability, as demonstrated by experimental results showing no fractures at the interfaces and a surface area ratio of 1.01 or more.
Implementation Method 1
a heat treatment at a temperature of about 1000° C. or more, an average rate of temperature increase from room temperature to a top temperature of about 1000° C. or more in the heat treatment step being 100° C./min or more
Implementation Method 2
an interdiffusion region from which both a metal constituent included in the plating layer and a metal constituent included in the internal electrodes are detected is provided in a boundary section between the plating layer and the internal electrodes
Implementation Method 3
a first plating layer including copper as a main constituent is formed on the exposed surfaces of the internal electrodes in the component main body
Data Source
AI summary
In a method of forming a plating layer for an external terminal electrode by applying, for example, copper plating to an end surface of a component main body with respective ends of internal electrodes exposed, and then applying a heat treatment at a temperature of about 1000° C. or more in order to improve the adhesion strength and moisture resistance of the external terminal electrode, the plating layer may be partially melted to decrease the bonding strength of the plating layer. In the step of applying a heat treatment at a temperature of about 1000° C. or more to a component main body with plating layers formed thereon, the average rate of temperature increase from room temperature to the temperature of about 1000° C. or more is set to about 100° C./minute or more. This average rate of temperature increase maintains a moderate eutectic state in the plating layer and ensures a sufficient bonding strength of the plating layer.