Multilayer Capacitor Laser Structuring for Stable Low-ESR Electrodes
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Solution Overview
Problem
Existing multilayer capacitors face challenges in achieving a balance between high withstand voltage, low equivalent series resistance (ESR), and stable connections to external electrodes, particularly due to the difficulty in forming uniform and stable concave-convex structures on the connection surfaces using plasma treatment.
Innovation Solution
The use of a laser beam scanning process to form cyclical concave-convex structures on the connection surfaces of capacitors, allowing for stable connections with external electrodes, thereby improving connectivity and reducing ESR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma treatment is used to form concave-convex structures on the connection surface, then the surface can be processed for metal spraying, but the structures are non-uniform and connection stability is insufficient
Solution Approach 1:
The patent replaces plasma treatment (chemical/physical process) with laser beam scanning (optical/thermal process) to form concave-convex structures on the connection surface. The laser beam melts and vaporizes the resin layers in a controlled manner, creating uniform periodic structures that provide stable anchoring for metal spraying, thereby resolving the non-uniformity issue of plasma treatment while maintaining connection reliability
Solution Approach 2:
The patent changes the processing parameters by using laser beam scanning with specific conditions (scan speed, power, pitch) to control the formation of concave-convex structures. By adjusting these parameters, uniform structures with controlled depth and periodicity are achieved, improving both manufacturing precision and connection stability compared to plasma treatment
2Stress or pressure
If electrode parts are made thinner to increase surface resistivity and withstand voltage, then withstand voltage increases, but connection resistance increases and ESR cannot be sufficiently reduced
Solution Approach 1:
The patent applies local quality by creating concave-convex structures only at the connection surface where electrodes connect to external terminals, while keeping the bulk electrode parts thin. The laser scanning forms periodic patterns that increase local surface area and metal penetration at connection points, providing low connection resistance locally without compromising the overall thin-electrode design for high withstand voltage
Solution Approach 2:
The patent transitions from a two-dimensional thin electrode structure to a three-dimensional concave-convex surface structure at the connection points. This dimensional change increases the effective connection area and provides deeper metal penetration paths, reducing connection resistance while maintaining the thin overall electrode thickness for high withstand voltage performance
3Reliability
If heavy edge structure is used to reduce connection resistance, then connection stability improves, but the capacitor size increases and high withstand voltage characteristics are compromised
Solution Approach 1:
The patent segments the electrode structure into two distinct regions: thin electrode parts for high withstand voltage in the bulk, and localized heavy edge structures at the connection surfaces formed by laser scanning. The concave-convex structures are created only at connection points, providing heavy edge benefits locally without increasing overall capacitor size, thus maintaining both small form factor and high withstand voltage characteristics
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 method enables the production of capacitors with enhanced withstand voltage, reduced ESR, and stable electrode connections, facilitating cost-effective manufacturing by eliminating the need for plasma treatment post-cutting.
Implementation Method 1
irradiating the connection surface with a laser beam, the connection surface can be processed so that the structure and/or shape of at least a part of the connection surface is cyclically changed
Implementation Method 2
it is possible to forcibly melt and vaporize not only the ends of the dielectric layers but also the ends of the electrode layers
Implementation Method 3
a mixed gas containing two or more of CF3, CF4, and O2 is activated and converted into plasma, a chemical dry etching process is performed
Data Source
AI summary
There is provided a capacitor (1) including a main body (10), in which a plurality of dielectric layers (13) and a plurality of electrode layers (11) are alternatively laminated, and an external electrode (20) that is connected to at least part of the main body. Before forming an external electrode by metal spraying (metallikon) on the main body, at least part of a connection surface (30) where the metal spraying is performed is scanned with a laser beam (51) so that scanning marks (55) composed of concave-convex structures (35) are formed by the laser beam on at least part of the connection surface.