MLCC Side Margin Composition for Insulation Resistance
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Solution Overview
Problem
The existing techniques for manufacturing multilayer ceramic capacitors face challenges in ensuring uniformity of internal electrode ends on side surfaces, leading to uneven stress and potential defects such as decreased insulation resistance due to concentrated electric fields.
Innovation Solution
The proposed solution involves a multilayer ceramic capacitor design where the side margin portions are composed of a polycrystalline body with a perovskite structure, including barium and titanium, with calcium or strontium added to the A site. These side margin portions have a higher atomic ratio of calcium or strontium to titanium compared to the ceramic layers, and they contain glass particles with silicon as the main component, dispersed in the polycrystalline body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If side margin portions are formed by punching out the ceramic sheet to cover internal electrode ends, then the size is reduced and capacity is increased, but the internal electrode ends on side surfaces become uneven and electric field concentration causes decreased insulation resistance
Solution Approach 1:
The patent applies local quality by forming side margin portions with a different composition than the main ceramic layers. Specifically, the side margin portions contain barium titanate along with calcium titanate and strontium titanate, creating a localized region with enhanced dielectric properties and stress distribution characteristics that prevent electric field concentration at the internal electrode ends.
Solution Approach 2:
The patent uses composite materials by combining multiple ceramic compounds (barium titanate, calcium titanate, strontium titanate) in the side margin portions. This composite structure provides both the mechanical integrity needed to cover the internal electrode ends and the electrical properties to distribute the electric field uniformly, thereby maintaining insulation resistance while enabling compact design.
2Volume of moving object
If side margin portions are made thin to reduce size, then capacity increases, but manufacturing precision becomes difficult to maintain uniformity
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the side margin portions. By incorporating calcium titanate and strontium titanate alongside barium titanate, the material properties are altered to improve sinterability and stress distribution. This enables the side margin portions to be formed with controlled thickness while maintaining uniform coverage over the internal electrode ends, achieving both size reduction and manufacturing precision.
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 design enhances the withstand voltage of the side margin portions, reducing the likelihood of defects such as decreased insulation resistance, even when the electric field is concentrated at the internal electrode ends. The inclusion of silicon improves sinterability and moisture resistance, contributing to higher reliability of the multilayer ceramic capacitors.
Implementation Method 1
each of the plurality of ceramic layers and the pair of side margin portions is composed of a polycrystalline body having a perovskite structure including barium in an A site and titanium in a B site
Implementation Method 2
a plurality of glass particles composed of silicon as a main component are dispersed in the polycrystalline body
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including ceramic layers, internal electrodes and a pair of side surfaces, and side margin portions, wherein each of ceramic layers and the side margin portions is composed of a polycrystalline body having a perovskite structure, wherein the side margin portions contain at least one of calcium and strontium, when the side margin portions contain calcium, an atomic ratio of the calcium to titanium in the side margin portions is greater than that in the ceramic layers, and when the side margin portions contains strontium, the atomic ratio of the strontium to titanium in the side margin portions is greater than that in the ceramic layers, wherein glass particles composed of silicon as a main component are dispersed in the polycrystalline body, and an atomic ratio of silicon to titanium is 1 at % or more and 10 at % or less.