Tantalum Capacitor Surface Terminal Design for ESR Reduction
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Solution Overview
Problem
Conventional tantalum capacitors face issues with elevated equivalent series resistance (ESR), limited capacitance, reduced mechanical strength, and increased manufacturing costs due to complex structures and limited contact areas, which affect their reliability and efficiency.
Innovation Solution
A tantalum capacitor design featuring a tantalum body with exposed tantalum wire, an insulating substrate without conductive materials, and a molded portion to enhance mechanical strength and reduce ESR, along with anodic and cathodic terminals connected through isolated paths to improve contact area and process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a via or patterned substrate is used to connect the electrode and external terminal, then electrical connection is achieved, but ESR characteristics deteriorate due to limited contact region
Solution Approach 1:
The patent transitions from point-contact via connections to surface-area terminal connections. The anodic and cathodic terminals are disposed on the surface of the capacitor body, enabling extensive surface contact between the terminals and the electrode rather than relying on limited via contact regions, thereby reducing ESR.
Solution Approach 2:
The patent divides the electrical connection into separate anodic and cathodic terminals that are independently disposed on the capacitor body surface. This segmentation allows each terminal to have optimized contact area with its respective electrode, improving overall contact region and ESR characteristics.
2Reliability
If a patterned substrate is used for connection, then electrical connection is achieved, but process efficiency reduces and manufacturing costs increase
Solution Approach 1:
The patent extracts the connection function from the substrate and implements it directly through terminals disposed on the capacitor body surface. This eliminates the need for complex patterned substrate manufacturing processes, thereby improving process efficiency while maintaining connection reliability.
Solution Approach 2:
The capacitor body surface serves multiple functions: it provides mechanical support, electrical insulation, and direct terminal mounting. This multi-functionality eliminates the need for separate patterned substrates, simplifying the manufacturing process and improving productivity.
3Reliability
If the substrate thickness is reduced, then capacitor capacity increases, but mechanical strength reduces due to complex structure
Solution Approach 1:
The patent employs a composite structure where the capacitor body combines dielectric material with embedded electrodes and terminals. This composite design provides both the electrical functionality for high capacitance and the mechanical strength necessary for structural integrity, even with reduced overall thickness.
Solution Approach 2:
The patent moves terminals to the surface of the capacitor body rather than requiring thick substrates for internal via connections. This dimensional change allows for thinner overall construction while maintaining mechanical strength through the distributed terminal support structure.
4Reliability
If a complex structure with via or patterned substrate is used, then electrical connection is achieved, but manufacturing costs increase
Solution Approach 1:
The patent extracts the connection functionality from complex patterned substrates and implements it through simple terminals disposed on the capacitor body surface. This simplification reduces manufacturing steps and material requirements, thereby lowering production costs while maintaining connection functionality.
Solution Approach 2:
Instead of embedding connections within the substrate (conventional approach), the patent inverts the approach by placing terminals on the surface of the capacitor body. This inversion simplifies the manufacturing process and reduces costs while achieving the same electrical connection functionality.
Data Source
AI summary
A tantalum capacitor includes a capacitor body comprising a tantalum body having a tantalum wire and a molded portion; an anodic terminal connected to the tantalum wire and disposed on the first surface of the capacitor body; an anodic connection portion connected to the anodic terminal and disposed on the fifth surface of the capacitor body; a cathodic terminal connected to the tantalum body and disposed on the second surface of the capacitor body; a cathodic connection portion connected to the cathodic terminal and spaced apart from the anodic connection portion on the fifth surface of the capacitor body; and a substrate disposed on the sixth surface of the body and on which the tantalum body is mounted, wherein the anodic terminal and the cathodic terminal are electrically isolated on the substrate.