Tantalum Capacitor PVD Anode Layer for Height Reduction
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Solution Overview
Problem
The manufacturing process for solid electrolytic capacitors is time-consuming and costly, with thick substrates and anode lead wires reducing volumetric efficiency and causing damage during processing.
Innovation Solution
A solid electrolytic capacitor design featuring a sintered porous anode body with a metallic physical vapor deposition (PVD) layer directly applied to the anode body, eliminating the need for seed layers and anode lead wires, and incorporating a dielectric and solid electrolyte for improved efficiency and reduced height profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a welded anode lead wire is used to connect the anode body, then electrical connection is achieved, but the weld energy causes deep penetration and significant damage in the weld area
Solution Approach 1:
A metallic PVD layer is deposited on the anode body to serve as an intermediary between the anode body and the anode lead wire. This intermediate layer distributes the weld energy over a larger area, preventing deep penetration and damage to the anode body while ensuring reliable electrical connection.
Solution Approach 2:
The invention changes the physical and chemical parameters of the anode surface by depositing a metallic PVD layer. This layer has different thermal and electrical properties than the porous anode body, allowing for controlled energy distribution during welding and reducing harmful effects.
2Reliability
If an embedded anode lead wire is used, then electrical connection is achieved, but the height profile of the capacitor increases
Solution Approach 1:
The metallic PVD layer merges the functions of the anode surface and the electrical connection interface. By integrating the connection function into the deposited layer rather than using a separate embedded wire, the overall height profile is reduced while maintaining electrical reliability.
3Ease of manufacture
If orthogonal cutting channels are made to remove seed material, then discrete capacitor elements are formed, but the manufacturing process becomes time-consuming and expensive
Solution Approach 1:
The invention extracts the problematic orthogonal cutting step from the manufacturing process. By using a planar seed layer that can be removed through conventional machining or chemical etching, the complex multi-axis orthogonal cutting is eliminated, significantly reducing manufacturing time and cost.
Solution Approach 2:
The planar seed layer serves as a simplified copy or approximation of the traditional three-dimensional seed structure. This planar version maintains the essential function of providing a bonding surface while eliminating the need for complex channel cutting.
4Ease of manufacture
If thicker substrates are used to accommodate cutting channels, then discrete capacitor elements can be formed, but volumetric efficiency is reduced
Solution Approach 1:
The invention changes the substrate thickness parameter by eliminating the need for deep cutting channels. The planar seed layer configuration allows for thinner substrates while still enabling discrete element formation, thereby improving volumetric efficiency.
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
The solution simplifies the manufacturing process, increases volumetric efficiency, and reduces the height profile of capacitors, addressing the inefficiencies and damage issues associated with traditional methods.
Implementation Method 1
a metallic physical vapor deposition (PVD) layer, where the metallic PVD layer is disposed directly on a planar surface of the porous anode body
Implementation Method 2
a dielectric, where the dielectric overlies at least a portion of the porous anode body
Data Source
AI summary
A solid electrolytic capacitor and method for making the capacitor are provided. The capacitor includes a sintered porous anode body formed from a valve metal, a metallic physical vapor deposition (PVD) layer disposed directly on a planar surface of the anode body, a dielectric, a cathode, and anode and cathode terminations. The dielectric overlies at least a portion of the anode body and is also formed within the anode body. The cathode overlies at least a portion of the dielectric that overlies the anode body and includes a solid electrolyte, and a portion of a lower surface of the metallic PVD layer is free of both the dielectric and solid electrolyte. The anode termination is electrically connected to the portion of the lower surface of the metallic PVD layer that is free of both the dielectric and solid electrolyte, and the cathode termination is electrically connected to the solid electrolyte.