Wiring Board Protrusion Layout for Fine-Pitch Pad Isolation

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Solution Overview

Problem

Narrowing the intervals between adjacent connection pads on wiring boards for high definition and miniaturization leads to increased short circuit risks and manufacturing difficulties.

Innovation Solution

A wiring board design featuring non-conductive protruding parts with a greater height than the connection terminals, arranged between adjacent pads to maintain spacing and protect the terminals, combined with a manufacturing method using materials with different thermal shrinkage rates to form these protrusions during heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the coating layer is formed to overlap and cover parts of the connection pads to prevent damage and foreign matter entry, then the connection terminals are protected, but the intervals between adjacent connection terminals cannot be narrowed

Engineering Contradiction:
Improveprotection of connection terminalsVSAvoidinterval between connection terminals
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The invention transitions from a two-dimensional planar coating approach to a three-dimensional protruding structure. By forming non-conductive protruding parts that rise vertically from the coating layer to a height exceeding the connection terminal height, the solution provides protection in the vertical dimension while maintaining horizontal spacing for narrow intervals between connection terminals.

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

Solution Approach 2:

The non-conductive protruding parts act as intermediary protective elements between the external environment and the connection terminals. These protrusions extend beyond the connection terminals to form an overhang that shields the terminals from damage and foreign matter entry without requiring the coating layer to cover the terminal surfaces directly.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the intervals between adjacent connection pads are narrowed for high definition and miniaturization, then the wiring board achieves higher definition and miniaturization, but the manufacturing difficulty increases and short circuit risk rises

Engineering Contradiction:
Improvedefinition and miniaturization of wiring boardVSAvoidmanufacturing difficulty and short circuit risk
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention resolves the manufacturing contradiction by adding vertical dimension to the protective structure. The non-conductive protruding parts extend vertically beyond the connection terminals, providing physical protection and electrical isolation that enables narrow horizontal intervals between terminals without increasing short circuit risk or manufacturing difficulty.

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

Solution Approach 2:

The protective function is localized to specific regions where connection terminals are present. The non-conductive protruding parts are formed only in areas corresponding to connection terminals, providing targeted protection while maintaining ease of manufacture through localized material deposition and processing.

Inventive Principle:
Principle #3Local quality

3Reliability

If the coating layer covers outer peripheral portions of pad conductors to prevent damage, then connection terminals are protected from surface damage and foreign matter, but the actual diameter of connection pads must be larger than exposed portions

Engineering Contradiction:
Improveprotection from surface damage and foreign matterVSAvoiddiameter relationship between actual and exposed connection pads
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The invention resolves the diameter constraint by transitioning to a three-dimensional protective structure. The non-conductive protruding parts extend vertically beyond the connection terminals, providing protection through vertical overhang rather than horizontal coverage. This allows the actual pad diameter to match the exposed portion diameter without compromising protection effectiveness.

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

Solution Approach 2:

Instead of having the coating layer extend horizontally beyond the connection terminals to provide protection, the invention inverts the approach by having protective protrusions extend vertically beyond the terminals. This inversion eliminates the need for larger actual pad diameters while maintaining comprehensive protection.

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 design effectively prevents short circuits and surface damage while allowing for close pad placement without narrowing intervals, enhancing manufacturing feasibility and reducing defect rates.

Implementation Method 1

heating or firing the insulating substrate on which the non-conductive material has been deposited, so as to allow the columnar parts to partially protrude from the insulating substrate due to a difference in thermal shrinkage rate between the insulating substrate and the columnar parts

Methodology Applied
Scientific EffectThermal shrinkage: Thermal Contraction

Data Source

PatentEP3740048B1Wiring board and manufacturing method thereof
Publication Date: 2025.08.13 NITERRA CO LTD
  • EP3740048B1 patent drawingFigure 1
  • EP3740048B1 patent drawingFigure 2
  • EP3740048B1 patent drawingFigure 3

AI summary

Disclosed is a wiring board including (1; 1a; 101; 201; 301): an insulating substrate (11); a plurality of connection terminals (12) arranged on the insulating substrate (11); and a plurality of non-conductive protruding parts (13; 113; 213; 313a; 313b; 313c; 313d; 313e; 313f) respectively arranged on areas of the insulating substrate (11) except areas on which the plurality of connection terminals (12) are arranged. The non-conductive protruding parts (13; 113; 213; 313a; 313b; 313c; 313d; 313e; 313f) has a height greater than that of the connection terminals (12).