Multilayer Ceramic Capacitor Electrode Structure for Low ESL Drift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multilayer ceramic capacitors face issues with deviations in equivalent series inductance (ESL), flex cracks, and insufficient adhesion strength of external electrodes, particularly when subjected to deformation or vibration.
Innovation Solution
A multilayer ceramic capacitor design featuring first and second external electrodes with band portions covering side surfaces, patterned electrodes with a specific area ratio, and a plating layer forming an intermetallic compound (IMC) layer, which reduces ESL deviation, increases adhesion strength, and decreases flex crack occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soft terminations using epoxy are applied to prevent flex cracks, then the occurrence of flex cracks is reduced, but adhesion strength remains insufficient and electrode layers may be easily peeled off
Solution Approach 1:
The patent applies patterned electrodes with specific area ratios (1:2 to 1:4 between exposed surface and patterned electrode) at specific locations on the band portion, creating localized regions of enhanced adhesion rather than uniform coverage. This local quality enhancement provides stronger bonding where needed while maintaining flexibility elsewhere.
Solution Approach 2:
The patent combines multiple materials including conductive epoxy resin containing copper, tin, or silver particles, plating layers, and intermetallic compound layers to create a composite electrode structure. This composite approach integrates the flexibility of epoxy with the adhesion strength of metal particles and intermetallic compounds.
2Ease of manufacture
If conventional external electrode structures are used, then manufacturing is simple, but equivalent series inductance (ESL) deviation increases
Solution Approach 1:
The patent optimizes the area ratio parameter between the exposed surface and patterned electrode on the band portion to a specific range (1:2 to 1:4). This parameter change controls the equivalent series inductance deviation while maintaining manufacturability through standard patterning processes.
Solution Approach 2:
The patent creates a dynamic electrode structure with patterned regions that can adapt to mechanical stress and deformation, allowing the electrode to maintain electrical performance under varying conditions while reducing ESL deviation.
3Ease of manufacture
If the external electrode structure is simplified, then manufacturing cost is reduced, but adhesion strength of external electrodes becomes insufficient
Solution Approach 1:
Instead of applying electrode material uniformly across the entire band portion, the patent uses partial action by applying patterned electrodes only to specific regions with controlled area ratios. This reduces material consumption and manufacturing cost while providing sufficient adhesion strength where needed.
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 effectively minimizes ESL deviation, enhances adhesion strength, and reduces the likelihood of flex cracks, while maintaining low manufacturing costs.
Implementation Method 1
an intermetallic compound (IMC) layer may exist at an interface between the plating layer and the exposed surface
Implementation Method 2
the exposed surface of the lower band portion of the external electrode and the patterned electrode are dense, surface roughness is high, so that the adhesion strength may increase
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A multilayer ceramic capacitor includes a ceramic body having a preset size of length, width, and thickness, first and second external electrodes respectively including body portions covering both end portions spaced apart from each other in a length direction of the ceramic body and band portions extending from the body portions and covering portions of both side surfaces of the ceramic body in a width direction and portions of both side surfaces of the ceramic body in a thickness direction, a plurality of first and second internal electrodes alternately led out from both end portions of the ceramic body with a dielectric layer interposed therebetween and connected to the first and second external electrodes, respectively, and a patterned electrode partially covering one surface of the band portion in the thickness direction of the ceramic body.