MLCC Margin Formation for Higher Sintering Density Reliability
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Solution Overview
Problem
Multilayer ceramic capacitors face issues with reduced moisture resistance reliability due to low sintering density in the margin portion and voids formed between internal electrodes and margin portions, leading to cracks and defects.
Innovation Solution
A method of manufacturing multilayer ceramic capacitors involves forming ceramic green sheets with internal electrode patterns, laminating them, cutting to expose internal electrode ends, and forming margin portions by flowing ceramic paste from the upper to the lower portion of the cut-out laminate, resulting in higher density margin portions that improve sintering density and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same dielectric composition is used for the margin portion as the ceramic body, then manufacturing process is simplified, but sintering density of the margin portion decreases and moisture resistance reliability degrades
Solution Approach 1:
The patent applies local quality by using a different dielectric composition for the margin portion compared to the ceramic body. The margin portion uses a dielectric composition with higher sintering density characteristics to specifically address the reliability issues at the interface region, while the main ceramic body maintains its original composition for capacitance functionality.
Solution Approach 2:
The patent changes the compositional parameters of the dielectric material in the margin portion. Specifically, it uses a dielectric composition that contains a different ratio of ceramic powders or additives that promote higher sintering density, thereby improving moisture resistance at the critical interface region between the margin and the ceramic body.
2Area of stationary object
If ceramic green sheets are laminated and cut to expose internal electrodes, then area of internal electrodes is increased, but step differences cause internal electrode patterns to bend and reliability lowers
Solution Approach 1:
The patent applies preliminary action by forming the margin portion before the final cutting step. The margin portion is created as an extended region on the ceramic green sheet that compensates for the step differences that will occur during cutting. This preliminary formation of the margin prevents bending of internal electrode patterns during subsequent processing.
Solution Approach 2:
The patent uses beforehand cushioning by creating a margin portion that acts as a buffer zone. This margin portion absorbs the mechanical stress and step differences generated during the cutting process, preventing the internal electrode patterns from bending or breaking, thereby cushioning the structure against reliability-degrading effects.
3Ease of manufacture
If margin portion is attached by physical compression, then adhesive force may be insufficient, but high-temperature heat treatment causes volume changes and voids form between electrode and margin portion
Solution Approach 1:
The patent merges the margin portion formation with the main ceramic body formation process. Instead of attaching a separate margin portion through compression and heat treatment, the margin is formed as an integral part of the ceramic green sheet structure before cutting, eliminating the interface between margin and body that would otherwise be prone to void formation.
Solution Approach 2:
The patent uses the ceramic green sheet material itself as an intermediary that ensures uniform density throughout the margin portion. By forming the margin from the same green sheet material that will become the ceramic body, the patent ensures consistent sintering behavior and eliminates the density mismatch that causes void formation during high-temperature heat treatment.
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
This approach enhances the moisture resistance reliability and prevents cracks by ensuring higher sintering density and uniform application of ceramic paste, resulting in improved performance and reliability of the multilayer ceramic capacitors.
Implementation Method 1
forming a margin portion on the side surface of the ceramic laminate, and wherein the forming a margin portion includes flowing a ceramic paste from an upper portion to a lower portion of the cut-out ceramic laminate
Implementation Method 2
forming a ceramic body including a dielectric layer and an internal electrode by firing the cut-out ceramic laminate
Data Source
AI summary
A method of manufacturing a multilayer ceramic capacitor includes preparing a ceramic green sheet in which a plurality of internal electrode patterns are formed with a predetermined distance therebetween, forming a ceramic laminate by laminating a plurality of the ceramic green sheets in a first direction, cutting the ceramic laminate to have a side surface from which an end of the internal electrode pattern is exposed in a second direction perpendicular to the first direction, forming a margin portion on the side surface from which the end of the internal electrode pattern is exposed, and forming a ceramic body including a dielectric layer and an internal electrode by firing the cut-out ceramic laminate. The forming a margin portion includes flowing a ceramic paste from an upper portion to a lower portion of the cut-out ceramic laminate.