Wiring Board Adhesion Promoting Layer for Short Circuit Prevention

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

As line widths and pitches on printed circuit boards shrink, abnormal interface penetration during electroless plating surface treatments can cause short circuits, affecting yield and reliability.

Innovation Solution

A wiring board design incorporating thin adhesion promoting material layers made of chlorinated polyolefin and olefin-based block copolymers, strategically positioned between solder mask and circuit layers, to enhance bonding forces and prevent abnormal interface penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If line width and line pitch are reduced to increase circuit integration, then circuit density is improved, but abnormal interface penetration occurs causing short circuits

Engineering Contradiction:

Improvecircuit densityVSAvoidshort circuit prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces an adhesion promoting material layer as an intermediary between the solder mask layer and the circuit board substrate. This intermediate layer prevents direct contact and potential penetration between the solder mask and conductive elements, thereby eliminating the short circuit issue while allowing continued miniaturization of line widths and pitches.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a composite structure consisting of multiple layers including the solder mask layer, adhesion promoting material layer, and circuit board substrate. This composite material approach creates a more reliable interface that prevents abnormal penetration while maintaining the electrical performance required for high-density circuits.

Inventive Principle:

Principle #40Composite materials

2Reliability

If electroless plating surface treatment is applied to improve conductivity, then electrical conduction is improved, but abnormal interface penetration occurs at opening interfaces

Engineering Contradiction:

Improveelectrical conductionVSAvoidinterface penetration control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The adhesion promoting material layer is applied in advance before the electroless plating process. This preliminary action creates a protective barrier that prevents interface penetration during subsequent plating operations, ensuring both good electrical conduction and precise interface control.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The adhesion promoting material layer serves as a mediator between the solder mask and the plated surface, preventing direct interface penetration while allowing the electroless plating to proceed and establish proper electrical connections.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If solder mask layer is applied to protect circuits, then circuit protection is improved, but abnormal interface penetration occurs at opening edges

Engineering Contradiction:

Improvecircuit protectionVSAvoidinterface penetration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The adhesion promoting material layer acts as an intermediary between the solder mask layer and the circuit board, preventing the harmful interface penetration effect while maintaining the protective function of the solder mask. This eliminates the short circuit risk at opening interfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies the adhesion promoting material specifically at the interface regions where penetration problems occur, rather than uniformly throughout the entire structure. This localized approach addresses the harmful interface penetration effect precisely where it occurs, maintaining circuit protection while eliminating the defect.

Inventive Principle:

Principle #3Local quality

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 avoids short circuits and ensures better soldering effects and electrical conduction characteristics, thereby improving yield and reliability of the wiring board.

Implementation Method 1

a first adhesion promoting material layer is formed on the first surface of the build-up circuit layer... a second adhesion promoting material layer is formed on the second surface of the build-up circuit layer and the patterned conductive layer

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS11166387B2Wiring board and manufacturing method thereof

Publication Date: 2021.11.02 UNIMICRON TECH CORP

AI summary

A wiring board including a build-up circuit layer, a patterned conductive layer, first and second adhesion promoting material layers and first and second solder mask layers is provided. The build-up circuit layer has a first surface and a second surface opposite thereto. The patterned conductive layer is disposed on the second surface. The first adhesion promoting material layer is disposed on the first surface and includes at least one first opening. The second adhesion promoting material layer is disposed on the second surface and the patterned conductive layer, and includes at least one second opening. The first solder mask layer is disposed on the first adhesion promoting material layer and includes at least one third opening provided corresponding to the first opening. The second solder mask layer is disposed on the second adhesion promoting material layer and includes at least one fourth opening provided corresponding to the second opening.