MLCC Copper Bump Structure for Stronger Electrode Adhesion
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Solution Overview
Problem
Conventional multilayer ceramic capacitors face issues with low adhesive strength between the capacitor main body and the bumps, leading to separation of the bumps from the capacitor main body.
Innovation Solution
The multilayer ceramic capacitor design includes outer electrode layers covering end and side surfaces of the multilayer body, with bumps made of copper that occupy a significant area in the cross-section, and a bump-producing paste composed of copper powder, epoxy resin, and solvent without a curing agent, enhancing the adhesive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If bumps are formed on the capacitor main body to cover outer electrodes, then acoustic noise is reduced, but adhesive strength between the capacitor main body and bumps becomes low
Solution Approach 1:
The invention changes the chemical composition parameters of the bump-producing paste by excluding curing agents and specifying the use of epoxy resin with particular molecular weight ranges (3,000-20,000), along with specific solvent types and ratios, to optimize adhesive strength while maintaining the acoustic noise reduction function
Solution Approach 2:
The invention uses a composite material formulation for the bump-producing paste consisting of copper powder (50-90 vol%), epoxy resin (5-30 vol%), and solvent (5-30 vol%), where the combination of these materials provides both the acoustic noise reduction property and improved adhesive strength to the capacitor main body
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 improves the adhesive strength between the capacitor main body and bumps, ensuring secure attachment to a mounting substrate and maintaining electrical conductivity.
Implementation Method 1
increase an adhesive strength between a capacitor main body and bumps
Implementation Method 2
a bump-producing paste for a multilayer ceramic capacitor according to an example embodiment of the present invention includes a copper powder, an epoxy resin, and a solvent
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including dielectric layers and internal electrode layers, outer electrode layers on end surfaces of the multilayer body at opposite ends in a longitudinal direction and covering end surface sides of each of principal surfaces of the multilayer body at opposite ends in a laminating direction and end surface sides of each of side surfaces at opposite ends in a width direction and bumps on the end surface sides of one principal surface of the multilayer body such that the outer electrode layers covering the one principal surface are sandwiched between the bumps and the one principal surface. Each bump includes copper covering an area of about 50% or more and about 96% or less in a cross section through widthwise centers of the bumps and extending in the laminating direction and the longitudinal direction.