Halogen-Free Prepreg for High Heat Resistance
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Solution Overview
Problem
Conventional laminates for semiconductor packages face challenges in achieving high heat resistance, chemical resistance, and flame resistance while avoiding the use of halogen compounds, particularly under severe conditions such as high temperatures and chemical treatments.
Innovation Solution
A prepreg composition is developed, comprising a naphthol aralkyl type cyanate ester resin, a nonhalogen epoxy resin, boehmite, and a silicone powder, with specific ratios and structures to enhance curability, heat resistance, and chemical resistance, and a metal-clad laminate is produced by laminating this prepreg with a metal foil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If aluminum hydroxide is used as a flame retardant, then flame resistance is improved, but resistance to chemical (alkali or acid) deteriorates
Solution Approach 1:
The invention uses a composite flame retardant system combining aluminum hydroxide with specific cyanate ester resins and silane coupling agents. This composite approach allows the aluminum hydroxide to provide flame resistance while the resin matrix and coupling agents protect against chemical degradation, resolving the contradiction between flame resistance and chemical resistance
Solution Approach 2:
Silane coupling agents are introduced as intermediaries between the aluminum hydroxide filler and the resin matrix. These coupling agents improve the interfacial bonding and chemical stability, preventing the resin from degrading under alkaline or acidic conditions while maintaining the flame retardant effect of aluminum hydroxide
2Ease of manufacture
If novolak type cyanate ester resins are used, then curability is improved, but water absorption coefficient increases and heat resistance after moisture absorption decreases
Solution Approach 1:
The invention modifies the chemical structure of cyanate ester resins by introducing specific aromatic hydrocarbon groups and controlling the ratio of cyanate groups to epoxy groups. This parameter optimization allows achieving good curability while maintaining low water absorption and high heat resistance after moisture absorption
Solution Approach 2:
The invention creates a composite resin system combining modified cyanate ester resins with epoxy resins and inorganic fillers. This composite structure balances the curability benefits of novolak-type resins while mitigating their high water absorption through the epoxy resin matrix and hydrophobic fillers
3Object-affected harmful factors
If bromine-containing flame retardant is used, then flame resistance is improved, but environmental compatibility deteriorates
Solution Approach 1:
The invention extracts and eliminates bromine-containing flame retardants from the composition, replacing them with aluminum hydroxide-based flame retardant systems. This removal of harmful halogen compounds maintains flame resistance through alternative mechanisms while improving environmental compatibility
Solution Approach 2:
The invention changes the flame retardant mechanism from halogen-based chemical inhibition to aluminum hydroxide-based thermal decomposition and char formation. This parameter change in the flame retardant chemistry eliminates environmental harm while maintaining effective flame resistance
Data Source
AI summary
A prepreg, for printed wiring boards, comprising a flame resistant resin composition containing a specific cyanate ester resin, a nonhalogen epoxy resin, boehmite which is hardly soluble in acids or alkalis and a silicone powder which is a flame retardant assistant, and a base material, which prepreg retains high-degree flame resistance without a halogen compound and has excellent resistance to chemical, high glass transition temperature, excellent soldering heat resistance and excellent heat resistance after moisture absorption, and a laminate or metal-foil-clad laminate obtained by curing the above prepreg.