Built-In Inductor Substrate With Local Plating for Uniform Thickness

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Solution Overview

Problem

Existing inductor built-in substrates face challenges in achieving high inductance and uniform signal transmission characteristics due to low magnetic material ratio and variations in conductor thickness.

Innovation Solution

The inductor built-in substrate incorporates a core substrate with first and second through-hole conductors, where the first through-hole conductors have a thicker electroless and electrolytic plating film than the second through-hole conductors, and are formed within a magnetic resin with iron oxide fillers, increasing the magnetic material ratio and balancing heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the electroless plating film thickness is increased in all through-hole conductors to improve signal transmission characteristics, then the conductor thickness uniformity improves, but the manufacturing complexity and cost increase due to requiring thicker plating throughout the entire substrate

Engineering Contradiction:

Improveconductor thickness uniformityVSAvoidplating process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies different electroless plating film thicknesses to different regions of the substrate. Specifically, the first through-hole conductors (in the magnetic resin region) have a first thickness, while the second through-hole conductors (in the non-magnetic resin region) have a second thickness that is different from the first. This local differentiation optimizes signal transmission characteristics in the magnetic region while reducing unnecessary plating thickness in non-magnetic regions, thereby improving conductor thickness uniformity where needed without uniformly increasing complexity across the entire substrate.

Inventive Principle:

Principle #3Local quality

2Reliability

If magnetic material ratio is increased to improve inductance, then the inductance value increases, but the substrate size and complexity increase

Engineering Contradiction:

Improveinductance performanceVSAvoidsubstrate size

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent divides the substrate into distinct regions: a first region containing magnetic resin with a first resin content and a second region containing non-magnetic resin with a second resin content. This segmentation allows magnetic material to be concentrated only where needed for inductance generation, rather than distributing it throughout the entire substrate. The magnetic resin region is specifically positioned to provide the required inductance while the non-magnetic regions maintain structural support and electrical isolation functions, thereby achieving high inductance without proportionally increasing overall substrate volume.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite material construction by combining magnetic resin and non-magnetic resin in a single substrate. The magnetic resin provides the necessary magnetic properties for inductance, while the non-magnetic resin provides structural support and electrical insulation. This composite approach allows the substrate to achieve high inductance performance through the magnetic resin portion while maintaining compact overall dimensions through the optimized non-magnetic resin structure, effectively decoupling inductance generation from overall substrate size expansion.

Inventive Principle:

Principle #40Composite materials

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 design enhances inductance and maintains good signal transmission characteristics by reducing thickness variations and improving heat dissipation, resulting in a compact substrate with improved performance.

Implementation Method 1

each of the first through-hole conductors includes an electroless plating film and an electrolytic plating film

Methodology Applied

Scientific EffectElectroless plating: Electroplating

Implementation Method 2

each of the first through-hole conductors includes an electroless plating film and an electrolytic plating film

Methodology Applied

Scientific EffectElectrolytic plating: Electroplating

Implementation Method 3

magnetic resin filling the openings and having second through holes formed therein

Methodology Applied

Scientific EffectMagnetic material property: Ferromagnetism

Data Source

PatentUS11856699B2Inductor built-in substrate

Publication Date: 2023.12.26 IBIDEN CO LTD

AI summary

An inductor built-in substrate includes a core substrate having openings and first through holes formed therein, a magnetic resin filling the openings and having second through holes formed therein, first through-hole conductors formed in the first through holes respectively such that each of the first through-hole conductors includes an electroless plating film and an electrolytic plating film, and second through-hole conductors formed in the second through holes respectively such that each of the second through-hole conductors includes an electroless plating film and an electrolytic plating film. The first through-hole conductors and the second through-hole conductors are formed such that a thickness of the electroless plating film in the first through-hole conductors is larger than a thickness of the electroless plating film in the second through-hole conductors.