Multilayer Ceramic Capacitor Convex Electrode Tombstone Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The miniaturization of multilayer ceramic capacitors leads to the 'tombstone phenomenon' when mounted on printed circuit boards, causing defects due to external electrode stand-up issues from surface tension during fusion welding.
Innovation Solution
A multilayer ceramic capacitor design with a ceramic body and external electrodes featuring mounting parts with a convexly curved shape and a corner radius of 50 μm or less, optimized in size to prevent tombstone phenomenon by increasing contact area with the printed circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the multilayer ceramic capacitor is miniaturized to meet the demand for smaller electronic devices, then the size of the capacitor is reduced, but the tombstone phenomenon occurs more frequently during mounting on printed circuit boards
Solution Approach 1:
The connection parts between the external electrodes and mounting parts are designed with a convexly curved shape having a corner radius of 50 μm or less. This curvature redistributes the surface tension forces during fusion welding, preventing the external electrodes from standing up and causing the tombstone phenomenon, while maintaining the miniaturized size of the capacitor.
2Reliability
If the corner radius of the connection parts is reduced to 50 μm or less to prevent tombstone phenomenon, then the tombstone phenomenon is suppressed, but the manufacturing precision requirement increases
Solution Approach 1:
The corner radius of the connection parts is precisely controlled to be 50 μm or less through parameter optimization. This specific geometric parameter change effectively prevents the tombstone phenomenon by altering the stress distribution during mounting, while the patent provides guidance for achieving this precision in manufacturing.
3Reliability
If the mounting part length is increased to improve contact area with the printed circuit board, then the mounting stability is improved, but the overall size of the capacitor increases
Solution Approach 1:
The mounting parts are extended onto the third surface of the ceramic body in a direction perpendicular to the stacking direction of internal electrodes. This dimensional optimization allows the mounting parts to have sufficient length (50-200 μm) for stable contact with the printed circuit board while maintaining a compact overall capacitor size through optimized spatial arrangement.
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 reduces tombstone phenomenon generation frequency, minimizing defects in printed circuit boards by ensuring proper mounting and contact between the capacitor and the board.
Implementation Method 1
an external electrode on any one side of external electrodes of the multilayer ceramic capacitor stands up in the manner of a tombstone due to the surface tension of fusion welding
Data Source
AI summary
There is provided a multilayer ceramic capacitor including: a ceramic body including dielectric layers and internal electrodes stacked between the dielectric layers; and a pair of external electrodes each fixed to first and second surfaces of the ceramic body, facing each other, and connected to the internal electrodes, wherein the ceramic body has a third surface facing a printed circuit board and each of the pair of external electrodes includes mounting parts extended onto the third surface and having a preset length by which they are mounted on the printed circuit board and wherein connection parts between the pair of external electrodes and the mounting parts have a convexly curved shape having a size equal to or smaller than a preset corner radius.