Resin Composition for High-Density PCBs via Photocuring

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Solution Overview

Problem

Existing resin compositions for multilayer printed wiring boards face challenges with poor light transmissivity and alkaline developability, leading to inhibited photocuring reactions and insufficient detail in resist patterns, particularly when using bismaleimide compounds and polyvalent carboxy group-containing compounds.

Innovation Solution

A specific carboxyl group-containing compound is used in the resin composition, allowing for effective photocuring and alkaline developability, enabling the production of high-density printed wiring boards with improved pattern detail and reduced processing time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a bismaleimide compound is used as a curable resin, then the resin composition can be cured by heating, but light transmissivity becomes poor and photocuring reaction is inhibited

Engineering Contradiction:
Improvecuring reliabilityVSAvoidlight transmissivity
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent changes the fundamental curing mechanism from thermal to photocuring by selecting curable resins with high light transmissivity (acrylic, vinyl, epoxy, phenolic resins) that can be cured by light irradiation rather than heating, thereby resolving the contradiction between curing reliability and light transmissivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite resin compositions combining multiple curable resins (acrylic, vinyl, epoxy, phenolic) with specific photoinitiators to achieve both high light transmissivity for photocuring and adequate curing reliability, eliminating the need for heating while maintaining pattern detail

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If conventional resin compositions are used, then processing can be performed, but alkaline developability is insufficient and unexposed resin remains after development

Engineering Contradiction:
Improvedevelopment processabilityVSAvoidpattern detail
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent modifies the chemical composition parameters by selecting specific curable resins and photoinitiators that provide inherent alkaline developability, allowing unexposed resin to be completely removed by alkaline developers while maintaining high pattern detail and eliminating residual unexposed material

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the need for additional chemical treatments or heating steps with a directly alkaline-developable resin composition that can be processed through simple exposure and development, simplifying the manufacturing process while improving pattern precision

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If heating is performed before development to cure maleimide compound, then curing can be achieved, but highly detailed resist patterns cannot be obtained

Engineering Contradiction:
Improvecuring completionVSAvoidresist pattern detail
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces thermal curing (heating) with photocuring using light irradiation and appropriate photoinitiators, eliminating the need for heating steps while achieving complete curing and highly detailed resist patterns with better alignment accuracy

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the curing activation parameter from temperature (heating) to light wavelength and intensity (photocuring), using specific photoinitiators that respond to light irradiation to achieve both complete curing and high pattern detail without thermal effects

Inventive Principle:
Principle #35Parameter changes

4Reliability

If laser processing is used for drilling holes, then conduction between insulation layers can be achieved, but processing time becomes longer as hole density increases

Engineering Contradiction:
Improveconduction reliabilityVSAvoidprocessing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces laser drilling with a photosensitive resin composition process where patterns are directly formed through light exposure and alkaline development, enabling batch processing of high-density substrates and significantly improving productivity while maintaining conduction reliability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs preliminary pattern formation on the resin composition layer before final assembly, allowing high-density wiring patterns to be created in advance through direct imaging or photomask exposure, reducing subsequent processing time and improving overall productivity

Inventive Principle:
Principle #10Preliminary action

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 compound enhances photocuring reactions and alkaline developability, enabling the production of high-density printed wiring boards with improved pattern detail and reduced processing time, addressing the limitations of existing resin compositions.

Implementation Method 1

a photo initiator (D) and a curable resin which is curable by a radical polymerization reaction or the like initiated by radicals generated by photolysis of the photo initiator (D)

Methodology Applied
Scientific EffectPhotolysis: Photodissociation

Implementation Method 2

a curable resin which is curable by a radical polymerization reaction or the like initiated by radicals generated by photolysis of the photo initiator (D)

Methodology Applied
Scientific EffectRadical polymerization: Photopolymerisation

Data Source

PatentEP4043419B1Compound and method for producing same, resin composition, resin sheet, multilayer printed wiring board, and semiconductor device
Publication Date: 2023.10.18 MITSUBISHI GAS CHEM CO INC
  • EP4043419B1 patent drawingFigure 1
  • EP4043419B1 patent drawingFigure 2
  • EP4043419B1 patent drawingFigure 3

AI summary

A compound (A) of the present invention is represented by the formula (1): wherein each R1 independently represents a group represented by the formula (2) or a hydrogen atom, and each R2 independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, provided that at least one R1 is a group represented by the formula (2); and wherein -* represents a bonding hand.