Multilayer Ceramic Capacitor Electrode Flatness for Wire Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multilayer ceramic capacitors connected by wire bonding face challenges with high-frequency impedance due to non-uniform external electrode thickness, leading to unreliable connections and reduced moisture resistance, especially as ceramic components are miniaturized.
Innovation Solution
A multilayer ceramic capacitor design with external electrodes having a difference of 3 μm or less in thickness between the center and peripheral portions, and an angle of 4 degrees or less in the field of view, featuring an underlying electrode layer with a metallic and ceramic component and a plating layer to ensure accurate wire bonding and improved moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the external electrode is formed by direct plating to achieve high accuracy, then the electrode thickness uniformity is improved, but moisture resistance is reduced due to moisture penetration between the electrode and ceramic body
Solution Approach 1:
The external electrode is formed as a composite structure with a first electrode layer containing a metallic component and a ceramic component, and a second electrode layer containing a metallic component. This composite configuration provides both thickness uniformity for wire bonding accuracy and inherent moisture barrier properties through the ceramic-containing first layer, resolving the contradiction between precision and moisture resistance.
2Ease of manufacture
If the external electrode thickness varies non-uniformly, then the wire bonding process becomes difficult with nozzle interference, but forming a uniform thickness electrode increases manufacturing complexity
Solution Approach 1:
The patent specifies precise parameter ranges for the external electrode: thickness difference of 3 μm or less between center and peripheral portions, and an inclination angle of 4 degrees or less. These controlled parameter changes enable reliable wire bonding by preventing nozzle interference while maintaining manufacturability through defined tolerances rather than overly complex processes.
3Reliability
If multiple wires are provided on the external electrode surface to reduce high-frequency impedance, then the impedance is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of adding multiple wires across the entire electrode surface, the patent applies local quality improvement by ensuring uniform thickness specifically in the wire bonding region (center and peripheral portions within 10% of the electrode length). This localized precision enables effective wire bonding with fewer wires, reducing high-frequency impedance without proportionally increasing overall device complexity.
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 design provides reliable wire bonding connections and enhanced moisture resistance, reducing high-frequency impedance and improving the functionality of ceramic electronic devices by ensuring a flat and uniform external electrode surface.
Implementation Method 1
an underlying electrode layer including a metallic component and a ceramic component, and a plating layer on the underlying electrode layer
Implementation Method 2
when the external electrode is formed by direct plating, moisture tends to penetrate between the external electrode and a ceramic body (a multilayer body) or the like into a ceramic electronic component, and there is a problem in that the ceramic electronic component has reduced moisture resistance
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including dielectric layers and internal electrode layers, and external electrodes electrically connected to the internal electrode layers. A difference of about 3 μm or less exists between a maximum thickness of a center portion of the external electrode and a thickness of a peripheral portion of the external electrode, and in a range of a field of view of about 50 μm square centered at a point located farther inward by about 15% than a peripheral end portion of the external electrode, an angle θ of about 4 degrees or less is defined by a straight line connecting two points of intersection of a surface of the external electrode and a sectional line defining the range of the field of view of about 50 μm square and a perpendicular line to a vertical line passing through one of the two points of intersection.