Modified Polyimide Film for High-Frequency Impedance Matching
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Solution Overview
Problem
Flexible circuit boards with conventional polyimide films have a high dielectric constant, making it difficult to achieve impedance matching for high-frequency signal transmission.
Innovation Solution
A resin composition comprising a modified polyimide compound, an epoxy resin, and a solvent, with a molar ratio of 0.1:1 to 1:1, which undergoes a polymerization reaction to form a polyimide film with reduced dielectric constant and improved thermal resistance, incorporating acrylate groups and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide groups for flame retardancy, and optionally including porous materials like MCM-41 for further dielectric reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyimide films are used in flexible circuit boards, then the film provides good mechanical flexibility and chemical stability, but the high dielectric constant (greater than 3.0) prevents impedance matching for high frequency signals
Solution Approach 1:
The patent modifies the polyimide molecular structure by incorporating fluorinated aromatic rings and controlling the degree of polymerization to reduce the dielectric constant from greater than 3.0 to 2.55-2.95, while maintaining the film's mechanical flexibility and chemical stability for high frequency signal transmission
Solution Approach 2:
The patent creates a composite polyimide system by combining modified polyimide compounds with specific diamine and anhydride components, achieving optimized dielectric properties (Dk < 3.0) while preserving the mechanical and thermal performance required for flexible circuit board applications
2Reliability
If the polyimide film is designed for high frequency signal transmission with reduced dielectric constant, then impedance matching is improved, but the thermal resistance during soldering processes may be compromised
Solution Approach 1:
The patent optimizes the polyimide molecular structure by adjusting the degree of polymerization to 1-50 and incorporating specific aromatic ring structures, achieving a balance between reduced dielectric constant (2.55-2.95) and maintained thermal stability for soldering process resistance
Solution Approach 2:
The patent uses a multi-component polymerization system with diamine and anhydride compounds that forms a cross-linked polyimide network, providing thermal stability during soldering while maintaining the low dielectric constant required for high frequency applications
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 resulting polyimide film exhibits a lower dielectric constant, enhanced thermal resistance, and improved flame retardancy, enabling effective impedance matching for high-frequency signals and maintaining structural integrity during soldering processes.
Implementation Method 1
A resin composition comprising a modified polyimide compound, an epoxy resin, and a solvent, with a molar ratio of 0.1:1 to 1:1, which undergoes a polymerization reaction to form a polyimide film
Data Source
AI summary
A resin composition comprises a modified polyimide compound, an epoxy resin, and a solvent. The modified polyimide compound has a chemical structural formula ofthe Ar′ represents a group selected from a group consisting of phenyl having a chemical structural formula ofdiphenyl ether having a chemical structural formula ofbiphenyl having a chemical structural formula ofhexafluoro-2,2-diphenylpropane having a chemical structural formula ofbenzophenone having a chemical structural formula ofand diphenyl sulfone having a chemical structural formula ofand any combination thereof, the modified polyimide compound has a degree of polymerization n of about 1 to about 50, the epoxy resin and the modified polyimide compound are in a molar ratio of about 0.1:1 to about 1:1. A modified polyimide compound and a polyimide film are also provided.