Multilayer Substrate with Non-Uniform Conductor Thickness

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Solution Overview

Problem

Existing multilayer substrates face issues with short circuits due to variations in conductor pattern thickness and spacing, which can lead to deformation and contact between patterns during manufacturing or mounting on circuit boards, resulting in unintended short circuits.

Innovation Solution

A multilayer substrate structure with specific thickness variations between conductor patterns on each surface, where the first conductor pattern has a smaller thickness and larger spacing to prevent line-to-line short circuits, and the use of interlayer connection conductors to connect patterns in parallel, reducing overall conductor loss and preventing short circuits during hot pressing and mounting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If plated films are thickened to reduce conductor pattern resistance, then conductor resistance decreases, but film thickness variation increases causing spacing inconsistency and potential short circuits

Engineering Contradiction:

Improveconductor resistanceVSAvoidfilm thickness uniformity

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent changes the physical state of the conductor pattern by applying plated films with controlled thickness variations. Instead of maintaining uniform thickness, the invention deliberately creates thicker portions at pattern edges and thinner portions in centers, which compensates for deformation during lamination and prevents short circuits while maintaining low resistance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention applies different plated film thicknesses to different locations of the conductor pattern. The edge portions receive thicker plating while center portions receive thinner plating, creating local quality variations that prevent both short circuits and excessive resistance

Inventive Principle:

Principle #3Local quality

2Productivity

If distance between adjacent conductor patterns is narrowed to increase density, then conductor arrangement density increases, but risk of short circuit between patterns increases

Engineering Contradiction:

Improveconductor pattern densityVSAvoidshort circuit prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention applies preliminary anti-action by creating thicker plated films at the edge portions of conductor patterns before lamination. This pre-compensates for the deformation that will occur during hot pressing, preventing the patterns from deforming into contact with each other and causing short circuits

Inventive Principle:

Principle #9Preliminary anti-action

3Manufacturing precision

If conductor pattern thickness is adjusted by grinding after plating, then thickness uniformity improves, but additional manufacturing steps are required and spacing variation in width direction cannot be controlled

Engineering Contradiction:

Improveconductor thickness uniformityVSAvoidmanufacturing process steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of grinding down thick portions to achieve uniform thickness, the invention inverts the approach by deliberately creating non-uniform thickness distribution during plating. The plated film is made thicker at edges and thinner in centers, which is the opposite of traditional uniform thickness requirements

Inventive Principle:

Principle #13The other way round (Inversion)

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 proposed structure effectively prevents short circuits between conductor patterns by maintaining consistent spacing and thickness variations, allowing for efficient mounting on circuit boards without increasing conductor loss, and facilitates thermal conduction and reduced resin flow during lamination.

Implementation Method 1

the growth rate (deposition rate) of the plated films varies depending on factors, such as the convection state of a plating solution in a plating bath, the electrode interval in the case of electroplating

Methodology Applied

Scientific EffectElectroplating: Electroplating

Implementation Method 2

Some existing multilayer substrates formed by laminating substrates having conductor patterns formed thereon together through hot pressing

Methodology Applied

Scientific EffectThermocompression bonding:

Data Source

PatentUS11114238B2Multilayer substrate, structure of multilayer substrate mounted on circuit board, method for mounting multilayer substrate, and method for manufacturing multilayer substrate

Publication Date: 2021.09.07 MURATA MFG CO LTD

AI summary

A multilayer substrate includes a lamination body including first and second resin substrates and a bonding layer that are hot-pressed. The first resin substrate includes a first surface provided with a first conductor pattern including a surface defined by a plated film, and a second surface provided with a second conductor pattern including a surface defined by a plated film. The second resin substrate includes a third surface provided with a third conductor pattern including a surface defined by a plated film, and a fourth surface provided with a fourth conductor pattern including a surface defined by a plated film. The first conductor pattern is located closer to a first outermost layer than the second conductor pattern. T1<T2 and T3<T4, where T1, T2, T3, and T4 respectively denote the thickness of the first, second, third, and fourth conductor patterns.