PCB Cavity Dummy Layer for Depth Control and Contact Protection

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Solution Overview

Problem

Existing methods for forming cavities in printed circuit boards face challenges in controlling cavity depth, damaging contact patterns, and accurately mounting electronic components.

Innovation Solution

A printed circuit board design featuring insulating layers, a cavity with contact portions, and a dummy layer on the cavity's side wall, along with a manufacturing method that includes forming contact portions, blocking layers, sacrificial layers, and dummy layers to control cavity formation and protect contact patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If cavity depth is increased to mount more electronic components, then component installation capacity is improved, but contact pattern damage risk increases

Engineering Contradiction:

Improvecomponent installation capacityVSAvoidcontact pattern integrity

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A dummy layer is introduced as an intermediary structure between the cavity bottom and the contact portions. This dummy layer serves as a protective mediator that prevents direct damage to contact patterns during cavity formation and component mounting processes, while still allowing the cavity to achieve sufficient depth for component installation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The dummy layer is formed in advance before the cavity is fully processed and before contact portions are finalized. This preliminary action establishes a protective structure that prevents subsequent damage to contact patterns during deeper cavity processing and component mounting operations.

Inventive Principle:

Principle #10Preliminary action

2Volume of moving object

If cavity depth is increased to reduce product thickness, then packaging efficiency is improved, but manufacturing precision deteriorates

Engineering Contradiction:

Improveproduct thicknessVSAvoidcavity depth control

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The dummy layer acts as a reference intermediary that facilitates precise cavity depth control. By forming the dummy layer with a known thickness and using it as a reference structure, the manufacturing process can achieve better depth precision even for deeper cavities, enabling product thinning while maintaining manufacturing accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If cavity depth control is improved to prevent contact pattern damage, then contact pattern integrity is improved, but component installation accuracy deteriorates

Engineering Contradiction:

Improvecontact pattern integrityVSAvoidcomponent installation accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The dummy layer serves as a dual-function intermediary: it protects contact patterns from damage during cavity formation while simultaneously providing a reference structure that improves component installation accuracy. The dummy layer's positioned structure allows both contact pattern protection and precise component placement.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250159802A1Printed circuit board and manufacturing method thereof

Publication Date: 2025.05.15 SAMSUNG ELECTRO MECHANICS CO LTD

AI summary

A printed circuit board includes: insulating layers; a cavity disposed in the insulating layers; contact portions disposed in the cavity; and a dummy layer disposed on a bottom portion of a side wall of the cavity and disposed between the insulating layers. A first thickness of the dummy layer is less than a second thickness of the contact portions.