Multilayer Coil Electrode Structure With Controlled Glass Diffusion
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Solution Overview
Problem
The existing multilayer coil components face insufficient bonding strength of outer electrodes, which can lead to failures in the interface between the electrodes and the multilayer body.
Innovation Solution
A multilayer coil component design featuring outer electrodes with a base electrode containing silver (Ag) and glass, where the glass has a diffusion length of 2.44 μm to 6.90 μm, enhancing the bonding strength by blurring the interface and acting as an adhesive, thereby improving the fixation strength to 3 N or more at a 1% failure probability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional outer electrodes are used without controlled glass diffusion, then the manufacturing process is simpler, but the bonding strength between outer electrodes and multilayer body is insufficient
Solution Approach 1:
The patent controls the diffusion length of glass from 2.44 μm to 6.90 μm by adjusting firing conditions (temperature, time, atmosphere), transforming the electrode structure from conventional to optimized. This parameter control enables sufficient bonding strength (fixation strength ≥3 N at 1% failure probability) while maintaining a relatively simple manufacturing process
Solution Approach 2:
The outer electrode uses a composite material consisting of Ag (silver) and glass, where the glass component diffuses into the multilayer body to create a gradient interface. This composite structure combines the electrical conductivity of Ag with the bonding and interface-blurring properties of glass, achieving both strong adhesion and electrical functionality
2Strength
If the interface between outer electrode and multilayer body is sharp and distinct, then the manufacturing precision is easier to control, but the bonding strength is insufficient leading to failures
Solution Approach 1:
The patent creates a localized gradient interface where glass diffusion occurs only in the region between the outer electrode and the multilayer body, with the diffusion length controlled to 2.44-6.90 μm. This local modification blurs the interface in the critical bonding zone while maintaining clear definitions elsewhere, achieving both strong bonding and acceptable manufacturing precision
Solution Approach 2:
The diffused glass acts as an intermediary material between the outer electrode and the multilayer body, creating a transition zone that gradually blends the two materials. This intermediary layer reduces stress concentration at the interface and enhances bonding strength, while the controlled diffusion length (2.44-6.90 μm) ensures the transition zone remains within manufacturable tolerances
3Strength
If glass diffusion length is too large (>6.90 μm), then the bonding strength increases, but stray capacitance increases and transmission coefficients deteriorate
Solution Approach 1:
The patent precisely controls the glass diffusion length parameter within the range of 2.44-6.90 μm by optimizing firing conditions. This parameter optimization achieves the minimum required bonding strength while limiting the diffusion extent to prevent excessive stray capacitance formation, thereby maintaining favorable transmission coefficients in high-frequency regions
Solution Approach 2:
The patent applies partial diffusion of glass (not complete or excessive diffusion) to achieve sufficient bonding strength. By limiting the diffusion length to 2.44-6.90 μm, the glass provides adequate adhesion and interface blurring without extending too far into the multilayer body, thus avoiding the harmful effect of excessive stray capacitance
4Object-affected harmful factors
If glass diffusion length is too small (<2.44 μm), then stray capacitance is reduced, but the bonding strength becomes insufficient
Solution Approach 1:
The patent optimizes the glass diffusion length parameter to be at least 2.44 μm by controlling firing conditions (temperature, time, atmosphere). This minimum diffusion length ensures sufficient bonding strength (fixation strength ≥3 N at 1% failure probability) while keeping stray capacitance at acceptable levels, achieving a balanced performance
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 described design significantly increases the bonding strength between the outer electrodes and the multilayer body, reducing the risk of failures and stray capacitance, while maintaining favorable transmission coefficients in high-frequency regions.
Implementation Method 1
a diffusion length of the glass from an interface between the outer electrode and the multilayer body toward the multilayer body is 2.44 μm or more and 6.90 μm or less
Data Source
AI summary
A multilayer coil component includes a multilayer body including insulating layers laminated in a lamination direction and a coil therein and outer electrodes that are at surfaces of the multilayer body and electrically connected to the coil. The multilayer body has first and second end surfaces facing each other in a length direction, first and second main surfaces facing each other in a height direction perpendicular to the length direction, and first and second side surfaces facing each other in a width direction perpendicular to the length and height directions. The outer electrodes include a first outer electrode extending from at least a portion of the first end surface to a portion of the first main surface and a second outer electrode extending from at least a portion of the second end surface to a portion of the first main surface.