Resin Composition for Printed Wiring Boards

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Solution Overview

Problem

Conventional resin compositions, particularly those containing bismaleimide compounds, face issues with poor light transmissivity, low reactivity, and poor alkaline-developability, limiting their use in high-density printed wiring boards and resulting in insufficient physical properties and tackiness in resin sheets.

Innovation Solution

A resin composition incorporating a specific bismaleimide compound with maleimide groups and additional maleimide compounds, along with a photo initiator and a compound containing carboxyl groups, enhances light transmissivity, photocurability, and alkaline-developability, while reducing tackiness in the resin sheet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional bismaleimide compounds are used as resin composition, then the resin sheet provides structural integrity, but the light transmissivity is poor and photocurability is low

Engineering Contradiction:
Improvelight transmissivityVSAvoidphotocurability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent combines conventional bismaleimide compounds with specific maleimide compounds containing ethylenically unsaturated groups (vinyl or allyl groups) to create a composite resin composition. This composite structure allows the material to maintain structural integrity while enabling effective light transmission and photocurability, as the maleimide compounds with unsaturated groups can undergo photo-initiated polymerization while the bismaleimide provides the base resin matrix

Inventive Principle:
Principle #40Composite materials

2Strength

If conventional bismaleimide compounds are used, then the resin provides mechanical strength, but alkaline-developability is poor

Engineering Contradiction:
Improvemechanical strengthVSAvoidalkaline-developability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent introduces maleimide compounds with specific functional groups (carboxyl, hydroxyl, or amino groups) that provide localized chemical reactivity for alkaline development. These functional groups are distributed within the resin matrix, creating local sites that can interact with alkaline developers while the overall bismaleimide structure maintains mechanical strength

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent modifies the chemical composition parameters of the resin by incorporating maleimide compounds with specific functional groups in controlled amounts (5-50 mass%). This parameter change enables the resin to achieve both mechanical strength and alkaline-developability, as the functional groups provide development sites while the bismaleimide matrix provides structural integrity

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional resin compositions are used, then the material provides adequate physical properties, but the resin sheet exhibits excessive tackiness

Engineering Contradiction:
Improvephysical propertiesVSAvoidtackiness
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the compositional parameters by incorporating specific maleimide compounds with functional groups that reduce surface tackiness. The presence of carboxyl, hydroxyl, or amino groups in the maleimide compounds modifies the surface properties of the cured resin, reducing tackiness while maintaining bulk physical properties through the bismaleimide matrix

Inventive Principle:
Principle #35Parameter changes

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 resin composition achieves improved solubility, photocurability, and alkaline-developability, leading to enhanced physical properties and reduced tackiness in resin sheets, suitable for high-density printed wiring boards and semiconductor devices.

Implementation Method 1

a resin composition in which an exposed portion is cured by, for example, irradiation of rays of light (exposure step)

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP4074740B1Resin composition, resin sheet, multilayer printed wiring board, and semiconductor device
Publication Date: 2024.11.20 MITSUBISHI GAS CHEM CO INC
  • EP4074740B1 patent drawingFigure 1
  • EP4074740B1 patent drawingFigure 2
  • EP4074740B1 patent drawingFigure 3

AI summary

Provided is a resin composition which has good solubility and photocurability, further has good alkaline-developability when containing a photo initiator and a compound containing one or more carboxyl groups, and in addition, is capable of providing a resin sheet having suppressed tackiness; and a resin sheet, multilayer printed wiring board, and semiconductor device using the same. The resin composition of the present invention contains a particular bismaleimide compound (A), and at least two maleimide compounds (B) selected from the group consisting of six kinds of particular compounds which are different from this bismaleimide compound (A).