Multilayer Ceramic Capacitor Barrier Ni Sn Void Reduction
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Solution Overview
Problem
The existing methods for producing small multilayer ceramic capacitors with high capacitance face issues due to voids formed between the laminate body and side margins during firing, which can lead to reduced insulation resistance and reliability, especially as dielectric layers become thinner.
Innovation Solution
The introduction of a barrier containing Ni and Sn on the widthwise end of internal electrode layers, which decreases in thickness towards the side margins, helps to improve insulation by reducing voids and enhancing the reliability of the multilayer ceramic capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If side margins are formed on side surfaces of the green chip by applying ceramic slurry, then the effective area of internal electrode layers is increased, but voids are generated between the laminate body and side margins during firing due to shrinkage rate difference
Solution Approach 1:
A barrier layer containing Ni and Sn is introduced as an intermediary substance between the internal electrode layers and the side margins. This barrier layer has different shrinkage characteristics that bridge the gap between the laminate body and side margins during firing, preventing void formation while maintaining the increased effective area of internal electrode layers.
Solution Approach 2:
The barrier layer is formed as a composite material containing both Ni and Sn elements. This composite structure provides both mechanical bonding to prevent voids and electrical insulation properties to maintain insulation resistance, effectively addressing both the area expansion requirement and the reliability concern.
2Quantity of substance
If dielectric layers are made thinner to increase capacitance density, then small multilayer ceramic capacitors with high capacitances are achieved, but the insulation resistance decreases due to void formation
Solution Approach 1:
The barrier layer acts as a mediator that becomes increasingly important as dielectric layers are thinned. It provides structural support and prevents void formation that would be more critical in thin-layer structures, enabling high capacitance density while maintaining insulation resistance through the void-prevention mechanism.
3Ease of manufacture
If the thickness of the barrier is constant, then manufacturing is simplified, but the barrier cannot effectively reduce voids at the interface between internal electrode layers and side margins
Solution Approach 1:
The barrier layer is designed with spatially varying thickness, being thicker at the interface between internal electrode layers and side margins where voids are most likely to form, and thinner in other regions. This local quality variation optimizes void prevention effectiveness while controlling manufacturing complexity.
Data Source
AI summary
A multilayer ceramic capacitor includes a laminate including dielectric layers and internal electrode layers laminated together in a lamination direction, and a pair of external electrodes on both end surfaces of the laminate, the external electrodes being connected to the internal electrode layers, wherein a barrier is provided on a widthwise end of at least one internal electrode layer, the barrier having a thickness that decreases from the widthwise end of the internal electrode layer toward a side margin in a width direction, a void is defined by the widthwise end of the internal electrode layer, the barrier, and the side margin, and the barrier contains Ni and Sn.