PCB Via with Conductive Ball for Low Resistance Current Transfer

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Solution Overview

Problem

Current printed circuit board technologies face limitations in efficiently transferring current between layers, leading to high power losses and thermal integrity issues, especially in miniaturized and harsh environments.

Innovation Solution

The use of high-conductivity balls, such as copper or copper alloys, within passages between conductive layers, along with solder for low ohmic contact, creates a secondary electrical path that enhances current transfer while maintaining low resistance and thermal management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional through-hole connections are used between conductive layers, then the structure is simple, but the current transfer capability is limited and power losses are high

Engineering Contradiction:
Improvepower lossesVSAvoidconnection structure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The connection structure is segmented into multiple functional components: conductive material on passage walls forming a first electrical path, and spherical conductors within the passage forming a second electrical path. This segmentation allows each component to contribute differently to current transfer, reducing overall power losses while distributing structural complexity across manageable elements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrical connection utilizes composite construction combining different conductive materials: conductive material deposited on passage walls and spherical conductors (such as copper balls) placed within the passage. This composite approach leverages the advantages of each material to achieve superior current transfer efficiency and reduced power losses compared to conventional single-material connections

Inventive Principle:
Principle #40Composite materials

2Power

If passage walls are used for current transfer between layers, then the structure is simple, but the current transfer capability is insufficient

Engineering Contradiction:
Improvecurrent transfer capabilityVSAvoidconnection structure complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The invention merges two distinct electrical paths into a single connection structure: the first electrical path through conductive material on passage walls and the second electrical path through spherical conductors within the passage. This merging creates a hybrid connection that achieves high current transfer capability while managing structural complexity through integrated design

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention transitions from a single-dimensional current transfer path (through passage walls) to a two-dimensional approach by adding spherical conductors as a second path. This dimensional expansion allows current to flow through multiple parallel routes, significantly increasing current transfer capability without proportionally increasing structural complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Volume of moving object

If miniaturization is pursued to reduce package size, then product demands are met, but thermal integrity and current distribution become compromised

Engineering Contradiction:
Improvepackage sizeVSAvoidthermal integrity
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The invention applies local quality enhancement by concentrating high-conductivity materials (spherical conductors and conductive wall material) specifically at the inter-layer connection points where current transfer and heat generation are most critical. This localized quality improvement maintains thermal integrity in miniaturized packages without requiring overall size increase

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The spherical conductors act as intermediary elements between conductive layers, providing both electrical connection and thermal management functions. These intermediaries facilitate efficient current transfer and heat dissipation in miniaturized packages, addressing both electrical and thermal requirements without compromising package size

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enables increased current transfer with reduced power losses and improved thermal management, maintaining stress within acceptable levels, and is cost-effective with low complexity in production.

Implementation Method 1

The passage encloses at least one first ball which is electrically conducting and which forms part of a second electrical path between the first and second conductive layers of the printed circuit board

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

The electrically conductive material is in low ohmic or low resistance contact with the surface of the at least one first ball

Methodology Applied
Scientific EffectSoldering: Soldering

Data Source

PatentEP2883430B1A printed circuit board arrangement and a method for forming electrical connection at a printed circuit board
Publication Date: 2022.10.05 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2883430B1 patent drawingFigure 1~2
  • EP2883430B1 patent drawingFigure 3~5
  • EP2883430B1 patent drawingFigure 6

AI summary

The present invention relates to a printed circuit board arrangement (400) and a method for forming an electrical connection at a printed circuit board. The printed circuit board arrangement comprises a printed circuit board (410) having a first side (411), a second side (412) and an electrical connection (413) electrically connecting a first conductive layer and a second conductive layer (417) of the printed circuit board. The electrical connection (413) comprises a passage (416) extending from an opening in one of the sides of the printed circuit board through the printed circuit board between the first and second layers. Electrically conducting material (414) is formed on the walls (415) of the passage. The electrically conducting material forms a first path electrically connecting the first conductive layer (417) with the second conductive layer (417). At least one first ball 420 is enclosed by the passage. The at least one firstball is electrically conducting and has a diameter which is equal to or smaller than the length and diameter of the passage, wherein the at least one first ball (420) form part of a second electrical path between the first and second conductive layers of the printed circuit board, said second electrical path having a lower resistance than the first path.