PCB Cavity Structure for Protecting Wiring During Laser Drilling

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Solution Overview

Problem

Current printed circuit board technologies face challenges in minimizing damage to wiring patterns during cavity formation and improving yield due to exposure and footing issues during the cavity formation process.

Innovation Solution

The use of an insulating material like thermosetting resist ink is applied to protect wiring patterns, followed by laser processing using CO2 drilling to form cavities, and subsequent removal of the insulating material remaining in the cavity, which prevents damage and reduces the occurrence of footings by forming a through-cavity structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional cavity formation process is used, then cavity can be formed, but wiring pattern damage occurs and footings are generated

Engineering Contradiction:

Improvecavity formation precisionVSAvoidwiring pattern integrity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

An insulating material is applied to the wiring pattern before cavity formation to protect it from damage during the laser drilling process. This preliminary protective action prevents wiring pattern damage while enabling precise cavity formation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The insulating material serves as an intermediary layer between the laser drilling process and the wiring pattern. It absorbs the harmful effects of the laser process and prevents direct damage to the wiring pattern, while still allowing the cavity to be formed through it.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Volume of moving object

If cavity formation process is applied, then package thickness is reduced, but footings occur in cavity

Engineering Contradiction:

Improvepackage thicknessVSAvoidcavity quality

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The insulating material is applied in advance to the cavity formation area before laser processing. This preliminary action prevents footing defects during cavity formation while maintaining the thickness reduction benefit.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The insulating material, which initially appears to add complexity, actually converts the harmful laser-direct-contact scenario into a beneficial protected process. The material absorbs excess energy and prevents footing formation, turning a potential defect source into a protective mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 approach effectively prevents damage to wiring patterns and reduces the occurrence of footings, enhancing product yield and allowing for improved design flexibility and cost-effective laser processing.

Implementation Method 1

forming the cavity by laser processing using CO2 drilling or the like

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentUS20240021486A1Printed circuit board

Publication Date: 2024.01.18 SAMSUNG ELECTRO MECHANICS CO LTD

AI summary

A printed circuit board includes a first insulating layer, a wiring pattern disposed in an upper side of the first insulating layer, a second insulating layer disposed on an upper surface of the first insulating layer and having a cavity exposing the wiring pattern, and an insulating pattern disposed between the first and second insulating layers, and having a side surface partially exposed by the cavity, while having an upper surface entirely covered by the second insulating layer.