Multilayer Ceramic Capacitor Electrodes for Void and Moisture Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multilayer ceramic capacitors face challenges in achieving high capacitance and moisture resistance due to the addition of low-melting-point metals in internal electrode layers, which cause voids and reduce reliability under high-temperature conditions.
Innovation Solution
A ceramic electronic component with internal electrode layers containing a low-melting-point metal and a specific aspect ratio, along with a manufacturing method that includes stacking dielectric and internal electrode layers alternately, forming base layers post-firing, and connecting external electrodes via solder, to enhance capacitance and moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If low-melting-point metals are added to internal electrode layers to improve capacitance, then capacitance increases, but voids form and moisture resistance deteriorates
Solution Approach 1:
The internal electrode layer is segmented into multiple metal components with different melting points. The patent uses Ni as the main component and adds low-melting-point metals (Sn, Pb, Zn, or Al) as secondary components, creating a composite structure where each metal serves a specific function in preventing void formation while maintaining capacitance.
Solution Approach 2:
The internal electrode layer employs a composite material structure combining Ni with low-melting-point metals (Sn, Pb, Zn, or Al) in specific ratios. This composite approach allows the electrode to benefit from both the high conductivity of Ni and the void-preventing properties of low-melting-point metals, resolving the contradiction between capacitance enhancement and moisture resistance.
2Quantity of substance
If aspect ratio is increased to improve capacitance density, then capacitance per volume increases, but manufacturing precision becomes more difficult
Solution Approach 1:
The patent optimizes the aspect ratio parameter to be 1.05 or more, which improves capacitance density while remaining manufacturable. Additionally, the patent specifies precise dimensional relationships between internal electrode layers and dielectric layers, controlling the ratio of their dimensions to ensure proper fit and function during manufacturing.
Solution Approach 2:
The patent applies different metal component ratios in different regions of the internal electrode layer. The low-melting-point metal content is controlled within specific ranges (0.1-5 wt% Sn, 0.1-3 wt% Pb, etc.) to locally optimize both capacitance and manufacturing feasibility without compromising overall dimensional control.
3Reliability
If Ni is used as main component of internal electrode layers to improve conductivity, then electrical conductivity increases, but voids form due to shrinkage mismatch
Solution Approach 1:
Low-melting-point metals (Sn, Pb, Zn, or Al) act as intermediary materials between the Ni matrix and the dielectric layer. These intermediaries have thermal expansion and shrinkage characteristics that bridge the mismatch between Ni and the ceramic dielectric, preventing void formation while maintaining the high conductivity provided by Ni.
Solution Approach 2:
The internal electrode layer is formulated as a composite material with Ni as the continuous phase providing conductivity and low-melting-point metals dispersed within it. This composite structure leverages the complementary properties of both metal types: Ni for conductivity and low-melting-point metals for shrinkage compatibility, eliminating voids.
Data Source
AI summary
A ceramic electronic component, in which a dimension in a first direction is equal to or greater than 1.3 times a dimension in a second direction orthogonal to the first direction, includes a multilayer chip including dielectric layers and internal electrode layers that are alternately stacked, the internal electrode layers containing Ni as a main component, the internal electrode layers being alternately exposed to first and second end surfaces facing each other in a third direction orthogonal to the first and second directions, and external electrodes provided on the first and second end surfaces, the external electrodes each including a plating layer on a base layer, wherein each internal electrode layer contains a metal component having a melting point of 700° C. or less, and an end in the first direction of at least one internal electrode layer of the internal electrode layers is in contact with a void.