Bismaleimide Resin for High-Frequency PCBs
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Solution Overview
Problem
Current insulating materials for high-frequency applications, such as bismaleimide resins, face challenges with low solvent solubility, brittleness, inadequate dielectric properties, and insufficient heat resistance, particularly in high-temperature environments.
Innovation Solution
A bismaleimide compound with a cyclic structure-containing tetravalent organic group and a dimer acid frame-derived divalent hydrocarbon group, combined with an aromatic ring-containing divalent group, is synthesized to enhance solubility, flexibility, and dielectric properties, achieving a low relative permittivity, dielectric tangent, and high glass-transition temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If bismaleimide resins are used for high-frequency applications, then heat resistance is improved, but solvent solubility deteriorates and the cured product becomes brittle
Solution Approach 1:
The patent modifies the molecular structure of bismaleimide resins by introducing specific cyclic structures ( formulas (1) and (2) ) and controlling molecular weight (3,000-50,000) to simultaneously achieve high heat resistance and improved solvent solubility. This structural parameter change resolves the contradiction between heat resistance and manufacturability.
Solution Approach 2:
The invention creates a composite resin system combining bismaleimide compounds with specific cyclic structures (formulas (1) and (2)) and controls the molecular weight distribution to achieve both high heat resistance and good solvent solubility, eliminating the need to choose between these opposing properties.
2Temperature
If bismaleimide resins are used for high-frequency applications, then heat resistance is improved, but the cured product becomes brittle and handling property deteriorates
Solution Approach 1:
The patent optimizes the molecular weight parameter (3,000-50,000) and introduces specific cyclic structures (formulas (1) and (2)) to achieve a balance between heat resistance and flexibility. The cyclic structures provide thermal stability while the controlled molecular weight prevents excessive brittleness.
3Temperature
If conventional bismaleimide resins are used, then heat resistance is achieved, but dielectric properties deteriorate
Solution Approach 1:
The patent introduces specific cyclic structures (formulas (1) and (2)) with controlled molecular weights to simultaneously achieve high heat resistance and excellent dielectric properties (low relative permittivity and dielectric tangent), resolving the contradiction between these two critical parameters for high-frequency applications.
4Reliability
If dimer acid frame-containing maleimide compounds are used, then dielectric properties are improved, but heat resistance deteriorates due to low Tg and high CTE
Solution Approach 1:
The patent creates a composite molecular structure combining dimer acid frame-derived groups (for good dielectric properties) with cyclic structures containing tetravalent organic groups (for high heat resistance). This composite approach at the molecular level achieves both low relative permittivity/dielectric tangent and high glass-transition temperature with low thermal expansion coefficient.
Solution Approach 2:
The invention introduces specific cyclic structures (formulas (1) and (2)) at key positions in the molecular chain to provide localized heat resistance enhancement without compromising the overall dielectric properties provided by the dimer acid frame structure. This local structural modification resolves the contradiction between dielectric performance and thermal stability.
5Temperature
If low molecular weight bismaleimide resins are used, then heat resistance is improved, but solvent solubility deteriorates and the cured product becomes hard and brittle
Solution Approach 1:
The patent optimizes the molecular weight parameter to a specific range (3,000-50,000) and introduces cyclic structures (formulas (1) and (2)) to achieve the optimal balance between heat resistance and solvent solubility. This parameter optimization resolves the contradiction between processing ease and thermal performance.
Data Source
AI summary
Provided is a bismaleimide compound where the compound itself has a superior solubility in various solvents; a resin composition containing this compound has a superior flexibility; and a cured product of such composition has a low relative permittivity and dielectric tangent, a low thermal expansion coefficient, and a superior heat resistance due to a high glass-transition temperature. The bismaleimide compound is represented by the following formula (1):wherein A independently represents a cyclic structure-containing tetravalent organic group; B independently represents a dimer acid frame-derived divalent hydrocarbon group; Q independently represents an aromatic ring-containing divalent group that has a fluorene frame or indene frame; W is B or Q; n is 1 to 100; m is 1 to 100; no restrictions are imposed on an order of each repeating unit identified by n and m, and a bonding pattern thereof may be alternate, block or random.