Ceramic Component Plating Film Adhesion
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Solution Overview
Problem
Ceramic electronic components, such as ceramic capacitors, face issues with plating films detaching during soldering to circuit boards, leading to reliability concerns.
Innovation Solution
The use of plating films with a surface area per unit area ratio (S ratio) of 1.02 or higher on external electrodes, made of materials like Cu or Cu alloys, and additional layers such as Sn or Ni alloys, which are designed to improve adhesion and solder wettability, preventing detachment and ensuring a strong bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plating films are used on external electrodes, then the manufacturing process is simple, but the plating films detach during soldering to circuit boards
Solution Approach 1:
The external electrode is segmented into multiple plating films with different materials and functions. The first plating film (Cu or Cu alloy) provides adhesion to the ceramic element, while the second plating film (Sn or Sn alloy) provides solder wettability. This segmentation allows each layer to specialize in one function, preventing detachment during soldering while maintaining manufacturing feasibility.
Solution Approach 2:
The external electrode uses composite plating film structure combining Cu-based material and Sn-based material. The Cu-based first plating film adheres to the ceramic element assembly, while the Sn-based second plating film provides solder wettability. This composite structure resolves the contradiction by combining materials with complementary properties to achieve both adhesion and solderability.
2Reliability
If the surface area of plating films is increased to improve soldering, then solder wettability improves, but the risk of plating film detachment increases
Solution Approach 1:
The plating film is segmented into two functional layers: the first plating film (Cu or Cu alloy) with controlled surface area provides adhesion to the ceramic element, while the second plating film (Sn or Sn alloy) with adequate surface area provides solder wettability. This segmentation allows the adhesive layer to maintain smaller surface area (reducing detachment risk) while the solderable layer has sufficient surface area for strong solder joints.
Solution Approach 2:
Different regions of the external electrode have different properties: the first plating film region has optimized adhesion properties with controlled surface area to prevent detachment, while the second plating film region has optimized solderability properties with adequate surface area for strong solder joints. This local quality differentiation resolves the contradiction between solder joint strength and detachment prevention.
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 plating film detachment and enhances solder wettability, resulting in improved reliability and performance of ceramic electronic components by controlling the surface area ratio of plating films within a specific range.
Implementation Method 1
the first and second external electrodes are formed by plating
Implementation Method 2
The first and second plating films each have a surface area per unit area equal to or larger than about 1.02... ceramic electronic component from which the plating films constituting the external electrodes are unlikely to detach
Implementation Method 3
The fifth plating film is preferably made of Sn or a Sn alloy... The sixth plating film is preferably made of Sn or a Ni alloy... enhances solder wettability
Data Source
AI summary
A ceramic electronic component includes a substantially rectangular ceramic element assembly, a first external electrode, and a second external electrode. The first external electrode includes at least one plating film including a first plating film disposed directly on the ceramic element assembly from outside. Likewise, the second external electrode includes at least one plating film including a second plating film disposed directly on the ceramic element assembly from outside. The first and second plating films each have a surface area per unit area equal to or larger than about 1.02 in plan view.