Bismaleimide Resin Composition for Low-Dielectric PCB Laminates
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Solution Overview
Problem
Existing thermally curable resins face challenges in achieving low dielectric characteristics, high heat resistance, low elastic modulus, and low water absorption rates, while also ensuring adhesiveness to substrates, due to issues such as phase separation, solvent residue, and insufficient heat resistance under temperature changes.
Innovation Solution
A thermally curable resin composition comprising a bismaleimide compound with maleimide groups at both ends of the molecular chain, combined with other curable resins and a polymerization initiator, which facilitates easy reaction and crosslinking, resulting in a cured object with improved adhesiveness, low dielectric properties, and reduced water absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If phenol novolac type cyanic acid ester resin is used, then heat expansion resistance is improved, but water absorption rate increases and dielectric characteristics deteriorate
Solution Approach 1:
The patent uses a composite resin system combining cyanic acid ester resin with other thermally curable resins (polyimide, phenolic, or epoxy) to achieve both heat expansion resistance and low water absorption. The synergistic combination allows the cured object to maintain excellent thermal properties while reducing water uptake compared to using cyanic acid ester resin alone.
2Strength
If thermoplastic high-molecular-weight polyamide imide resin is used, then mechanical strength and adhesive strength are improved, but low-temperature meltability deteriorates and phase separation occurs
Solution Approach 1:
The patent changes the molecular weight parameter of the polyamide imide resin from high-molecular-weight to low-molecular-weight, enabling the resin to melt at lower temperatures and maintain good flowability during lamination while still achieving adequate mechanical strength after curing.
Solution Approach 2:
The patent discards the high-molecular-weight polyamide imide resin that causes processing difficulties and recovers the essential functional properties (adhesiveness and mechanical strength) by using low-molecular-weight polyamide imide resin combined with other curable resins that provide the necessary strength after curing.
3Strength
If epoxy resin composition is used, then adhesiveness is improved, but heat resistance deteriorates due to cracks under temperature cycling
Solution Approach 1:
The patent creates a composite curing system where epoxy resin provides adhesiveness and crosslinks with cyanic acid ester resin or other thermally curable resins to form a synergistic network. This composite structure maintains strong adhesion while developing superior heat resistance and crack resistance under temperature cycling compared to epoxy resin alone.
Solution Approach 2:
The patent merges the curing mechanisms of epoxy resin with cyanic acid ester resin or other thermally curable resins, combining the adhesive benefits of epoxy with the thermal stability of the other resins to achieve both high adhesiveness and excellent heat resistance in the cured object.
4Stability of the object's composition
If high-boiling-point solvent such as NMP is used, then resin compatibility is improved, but solvent remains in the B stage causing voids
Solution Approach 1:
The patent extracts and removes the high-boiling-point solvent (NMP) from the resin composition, replacing it with solvent-free or low-solvent formulations. This eliminates the harmful residue and void formation while maintaining resin compatibility through proper formulation of the thermally curable resin components.
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 composition achieves low-dielectric, high-heat-resistant, and low-water-absorption properties, enhancing the performance of laminates and electronic components by improving adhesiveness and reducing voids.
Implementation Method 1
a bismaleimide compound (A) including a constituent unit represented by the following Formula (1) and maleimide groups at both ends of a molecular chain, a thermally curable resin or compound (B) other than the bismaleimide compound (A), and a polymerization initiator (C) and/or a curing accelerator (D)
Data Source
AI summary
Provided is a thermally curable resin composition which can give cured objects having low-dielectric characteristics, high heat resistance, a low modulus, and a low water absorption and which has satisfactory adhesiveness to substrates. The thermally curable resin composition comprises: a bismaleimide compound (A) including a constituent unit represented by formula (1) and containing maleimide groups at both ends of the molecular chain; a thermally curable resin or compound (B); and a polymerization initiator (C) and/or a curing accelerator (D).