Polyimide Resin Composition for Low-k and Low Thermal Expansion

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Solution Overview

Problem

Existing polyimide resins for high-frequency substrates face a challenge in simultaneously achieving a low dielectric constant and a low linear expansion coefficient, as these properties are generally in a trade-off relationship.

Innovation Solution

A polyimide resin composition comprising specific acid anhydrides and diamines, defined by certain chemical formulas, which are optimized through molecular dynamics simulation to achieve a low dielectric constant and low linear expansion coefficient, characterized by specific free volume fraction and average neighboring atom number.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If polyimide resin is designed to achieve low dielectric constant, then dielectric constant is reduced, but linear expansion coefficient increases

Engineering Contradiction:
Improvedielectric constantVSAvoidlinear expansion coefficient
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical structure parameters of the polyimide resin by introducing specific fluorinated cyclic structures and controlling the ratio of aromatic to aliphatic components. This structural parameter modification enables simultaneous reduction of dielectric constant to 2.6 or less and linear expansion coefficient to 50 ppm/K or less, resolving the trade-off relationship between these two properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite molecular structure within the polyimide resin by combining fluorinated cyclic acid anhydride units with specific diamine units. This composite approach at the molecular level allows the material to exhibit both low dielectric constant and low linear expansion coefficient properties that cannot be achieved with single-structure polyimides.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If polyimide resin is designed to achieve low linear expansion coefficient, then linear expansion coefficient is reduced, but dielectric constant increases

Engineering Contradiction:
Improvelinear expansion coefficientVSAvoiddielectric constant
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent modifies the molecular structure parameters by incorporating fluorinated cyclic structures and controlling the aromatic/aliphatic ratio. This structural change simultaneously achieves low linear expansion coefficient (50 ppm/K or less) and low dielectric constant (2.6 or less), overcoming the inverse relationship between these properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite molecular architecture combining fluorinated cyclic acid anhydride units with specific diamine units. This composite structure enables the polyimide resin to exhibit both low thermal expansion and low dielectric constant properties, resolving the contradiction between these two characteristics.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP4663687A1Polyimide resin for high-frequency substrate material, composition, polyimide film, laminate, substrate for circuit, antenna, polyamic acid for high-frequency substrate material, and composition
Publication Date: 2025.12.17 DAIKIN INDUSTRIES LTD
  • EP4663687A1 patent drawingFigure 1~2
  • EP4663687A1 patent drawingFigure 3
  • EP4663687A1 patent drawingFigure 4

AI summary

A polyimide resin for a high-frequency substrate material includes an acid anhydride and a diamine. The acid anhydride is one or more selected from the group consisting of compounds represented by general formula (A-1) below, and the diamine is one or more selected from the group consisting of compounds represented by general formula (B-1) below and compounds represented by general formula (B-2) below: and