Thin Laminate Passive Devices Preventing Electrical Shorts

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Solution Overview

Problem

Existing thin laminate passive electrical devices in PCBs face challenges in preventing electrical shorts due to surface asperities and susceptibility to foreign matter during the lamination process, which compromises the separation between conductive foils and affects their electrical performance.

Innovation Solution

A three-layer laminate structure is introduced, comprising two copper foils sandwiched between two dielectric layers, where one dielectric layer has a high softening point temperature to maintain stability under lamination conditions and the other has a lower softening point to facilitate bonding, minimizing the risk of electrical shorts and ensuring high electrical voltage resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a thin insulating layer is used between conductive foils to reduce laminate thickness, then the device size is reduced, but the risk of electrical shorts due to surface asperities increases

Engineering Contradiction:

Improvelaminate thicknessVSAvoidelectrical shorting resistance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The conductive foils are pre-coated with a dielectric material before lamination to create a protective barrier that prevents electrical shorts caused by surface asperities, eliminating the need for post-processing treatments

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A composite laminate structure is formed combining conductive foils with dielectric material layers, creating a multi-layer composite that maintains electrical isolation while achieving thin overall thickness

Inventive Principle:

Principle #40Composite materials

2Strength

If lamination is performed at high temperature to improve bonding, then the bonding strength is enhanced, but the insulating material may flow away due to reduced viscosity

Engineering Contradiction:

Improvebonding strengthVSAvoidinsulating material position stability

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The dielectric material is selected with specific thermal properties (glass transition temperature above lamination temperature) to maintain its structural stability and prevent flow during high-temperature lamination while still enabling adequate bonding

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the surface of conductive foils is made smooth to minimize asperities, then electrical shorting is reduced, but the bonding area and strength are decreased

Engineering Contradiction:

Improveelectrical shorting resistanceVSAvoidbonding strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

Dielectric material is applied in advance to the conductive foil surfaces, creating an insulating barrier before lamination that prevents shorts without requiring smooth foil surfaces, thereby preserving the original bonding characteristics

Inventive Principle:

Principle #10Preliminary action

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 solution effectively prevents electrical shorts and maintains the desired separation between conductive foils, enhancing the reliability and performance of passive electrical devices like capacitors by using a composite polymer-layer structure that resists deformation under lamination temperatures and pressures.

Implementation Method 1

a first layer of insulating material comprising a material having thermal deformation resistance adequate to resist deformation under conditions experienced during fabrication

Methodology Applied

Scientific EffectThermal deformation resistance:

Implementation Method 2

since the insulating layer 26 experiences a reduction in viscosity due to the elevated temperature at which lamination takes places, that is, at a temperature of at least 150 degrees C.

Methodology Applied

Scientific EffectViscosity reduction due to temperature:

Implementation Method 3

a first layer of insulating material comprising a material having thermal deformation resistance adequate to resist deformation under conditions experienced during fabrication and thereby provide a passive electrical device having improved resistance to electrical shorting

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS8866018B2Passive electrical devices and methods of fabricating passive electrical devices

Publication Date: 2014.10.21 MITSUI MINING & SMELTING CO LTD

AI summary

A thin laminate passive electrical device, such as, a capacitor, and a method of fabricating a thin laminate passive electrical device are provided. The passive electrical device includes two conductors, for example, copper foil conductors, separated by a dielectric having a first layer of a first material having a softening point temperature greater than a first temperature and a first layer of a second material having a softening point temperature less than the first temperature. The first temperature may be at least 150 degrees C. or higher. By providing a first layer having a higher softening point material, shorting across the conductors, that can be promoted by the fabrication process, is prevented. Methods of fabricating passive electrical devices are also disclosed.