Multilayer Coil Component Via Hole Positioning

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Solution Overview

Problem

Multilayer coil components experience reduced inductance due to small inside diameter and stress concentration caused by the placement of pads and via hole conductors, leading to lamination shifts and decreased performance.

Innovation Solution

The via hole conductors and pads are positioned on the outer side of the spiral coil in the coil-conductor-width direction, reducing overlap and stress concentration, and maintaining a larger inside diameter, while also distributing via hole conductors in a staggered manner to prevent short-circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pads and via hole conductors are positioned toward the inner side of the spiral coil to provide side gaps, then side gaps are reliably provided, but the inside diameter of the spiral coil becomes small resulting in reduction of inductance

Engineering Contradiction:

Improveside gap provisionVSAvoidinside diameter of spiral coil

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent inverts the conventional positioning approach by placing the via hole conductors toward the outer side of the spiral coil instead of the inner side. This inversion allows the inside diameter to be maximized while side gaps are still provided between adjacent turns of the coil, thereby preventing inductance reduction.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If pads and via hole conductors are positioned toward the inner side of the spiral coil, then side gaps are provided, but large pressure is applied during contact bonding causing flattening and further reduction of inside diameter

Engineering Contradiction:

Improveside gap provisionVSAvoidinside diameter of spiral coil

Core Design Contradiction:

ReliabilityVSShape

Solution Approach 1:

By inverting the position of via hole conductors to the outer side of the spiral coil, the patent eliminates the concentration of pressure on the inner side during contact bonding. This prevents flattening of the coil structure and maintains the intended inside diameter geometry.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If pads and via hole conductors are positioned toward the inner side of the spiral coil, then side gaps are provided, but stress is concentrated at these locations resulting in reduced inductance

Engineering Contradiction:

Improveside gap provisionVSAvoidstress concentration at pads and via hole conductors

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent resolves stress concentration by inverting the position of via hole conductors from the inner side to the outer side of the spiral coil. This distribution of via hole conductors away from the inner perimeter reduces stress concentration and prevents inductance reduction.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies local quality by positioning via hole conductors at specific locations (outer side) where they do not interfere with the magnetic field distribution and stress patterns of the spiral coil, thereby optimizing both mechanical and electrical performance.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS7378931B2Multilayer coil component

Publication Date: 2008.05.27 MURATA MFG CO LTD

AI summary

A multilayer coil component is formed such that ceramic green sheets having coil conductors and via hole conductors are laminated. The multilayer coil component includes therein a spiral coil in which the coil conductors are connected in series through the via hole conductors. In plan view in a lamination direction, the via hole conductors are located in positions spaced toward the outer side of the spiral coil, the positions being located near end surfaces in a long side direction of a multilayer body.