Resin Sheet with Inorganic Layer for PCB Insulating Flatness

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Solution Overview

Problem

The challenge is to achieve an insulating layer with small surface undulations and suppress the haloing phenomenon in printed wiring boards, especially when using thin resin composition layers, as existing methods result in faulty adhesion and unevenness due to surface undulations and degradation around via holes.

Innovation Solution

A manufacturing method involving a resin sheet with an inorganic layer, comprising a support with an inorganic layer and a release layer, laminated onto an internal substrate, cured to form an insulating layer, and then perforated using a CO2 or UV laser, where the inorganic layer thickness is optimized to ensure flatness and prevent haloing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a thin resin composition layer is used to form the insulating layer, then the insulating layer thickness is reduced (achieving downsizing), but surface undulations occur corresponding to the internal layer circuit substrate, causing faulty adhesion and unevenness

Engineering Contradiction:
Improveinsulating layer thicknessVSAvoidsurface flatness
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

A release layer is introduced as an intermediary between the resin composition layer and the support. This release layer has controlled adhesion properties that allow the resin to be applied uniformly while preventing excessive adhesion to the support, thereby reducing surface undulations in the cured insulating layer even when using thin resin composition layers.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The adhesion strength between the resin composition layer and the support is adjusted by modifying the release layer properties. By controlling the adhesion parameter (through release layer material selection or thickness adjustment), the resin can be applied with minimal surface undulation, achieving both thinness and flatness in the insulating layer.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If a thin resin composition layer is used, then downsizing is achieved, but a haloing phenomenon occurs around via holes causing degradation and interlayer peeling

Engineering Contradiction:
Improveinsulating layer thicknessVSAvoidconduction reliability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The release layer serves as a mediator that controls the interaction between the resin composition layer and the support during via hole formation. This controlled adhesion prevents the haloing phenomenon by reducing excessive resin adhesion to the support, thereby preventing degradation and interlayer peeling while maintaining thin insulating layer dimensions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The release layer is applied beforehand to prevent the haloing phenomenon. By establishing this release layer prior to resin application and via hole formation, the patent preemptively counteracts the adhesion issues that would otherwise cause degradation and peeling around via holes in thin insulating layers.

Inventive Principle:
Principle #9Preliminary anti-action

3Device complexity

If conventional lamination is used without a release layer, then the process is simple, but surface undulations cause faulty adhesion with pattern-forming dry film

Engineering Contradiction:
Improvemanufacturing process complexityVSAvoidadhesion quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

A release layer is introduced as an intermediary component between the resin composition layer and the support. This additional layer, while increasing process complexity slightly, dramatically improves adhesion quality by controlling resin-surface interaction and minimizing surface undulations, enabling reliable pattern formation.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Device complexity

If conventional lamination without optimized inorganic layer is used, then manufacturing is simpler, but unevenness in roughness occurs after roughening treatment

Engineering Contradiction:
Improvemanufacturing process complexityVSAvoidsurface roughness uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The release layer acts as an intermediary that ensures uniform resin distribution and minimizes surface undulations during lamination. This preliminary control of surface flatness before roughening treatment ensures that the roughening process produces uniform roughness across the insulating layer surface, improving subsequent wiring formation.

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 method effectively reduces surface undulations and haloing, enhancing the reliability of electrical connections by maintaining flatness and preventing interlayer peeling, even with thin resin layers, thus improving the conduction reliability of printed wiring boards.

Implementation Method 1

perforating the insulating layer using a CO2 laser or a UV laser... suppress a haloing phenomenon... inorganic layer thickness is optimized to ensure flatness and prevent haloing

Methodology Applied
Scientific EffectLaser absorption: Absorption (EM radiation)

Data Source

PatentUS12120827B2Method for manufacturing printed wiring board and resin sheet with inorganic layer
Publication Date: 2024.10.15 AJINOMOTO CO INC

AI summary

Provided is a technique that can achieve an insulating layer with small surface undulations and can suppress a haloing phenomenon in manufacturing a printed wiring board even when using a thin resin composition layer. Specifically, provided is a method for manufacturing a printed wiring board that includes the steps of: (A) preparing a resin sheet with an inorganic layer including (i) a support with an inorganic layer including an inorganic layer, a support in contact with the inorganic layer, and a release layer and (ii) a resin composition layer in contact with the release layer of the support with an inorganic layer; (B) laminating the resin sheet with an inorganic layer onto an internal layer substrate so that the resin composition layer of the resin sheet with an inorganic layer is in contact with the internal layer substrate; (C) curing the resin composition layer to form an insulating layer; and (D) perforating the insulating layer.