A flame-retardant copper-clad laminate composite made of (metallocenebased cyclic olefin copolymer/glass)/ cresol-novolak epoxy with low dielectricity

Abstract

A CNE (cresol-novolak epoxy) composite of CCL (copper-clad laminate), comprising glass fabrics and mCOC (metallocenebased cyclic olefin copolymer) fabrics with various laminated structures, was fabricated and its dielectricity at high frequency was examined. The dielectric constant, D k , at 5 GHz of a conventional glass/CNE composite is 4.0, whereas that of a seven alternately layered mCOC/glass/CNE composite with an externally facing mCOC layer is 2.3. In the same manner, the former has a loss tangent, D f , of 0.035, whereas the latter has a loss tangent, D f , of 0.007. In addition, the decrease of D f with increasing mCOC content is not linear but logarithmical. The T g (glass transition temperature) and scanning electron microscope results reveal the good compatibility of the mCOC and CNE at the interface between them. An optimal compression process, which involved a pressure of 20 kg/cm 2 at 185 C for 120 min, was followed by setting at 120 C for 30 min, to relax the residual stress that built up inside the mCOC prepregs, with the purpose of fabricating a mCOC/glass/CNE CCL without any tilt angle. The worsening of the flame retardancy that is caused by replacing some of the nonflammable glass layers with organic mCOC layers can be overcome by blending more 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide dicyandiamide hardener into the CNE matrix. The highest flameretardant standard, of grade UL 94 V0, can be achieved with a phosphorus content of the glass/CNE and glass/ mCOC/CNE CCLs of 8000 and 12,500 ppm, respectively. Briefly, a flame-retardant mCOC/glass/CNE composite of CCL operated at high frequency is successfully produced.

A mini‐review of ultra‐low dielectric constant intrinsic epoxy resins: Mechanism, preparation and application

“…83 As the performance and running speed of electronic equipment will be greatly improved, thus the higher requirements of PCB substrates will be put forward. Rwei et al 84…”

“…As the performance and running speed of electronic equipment will be greatly improved, thus the higher requirements of PCB substrates will be put forward. Rwei et al 84 employed the phenolic‐formaldehyde‐based epoxy resins for PCB. The corresponding ε and tan δ values were 2.3 and 0.007 at 5 GHz, respectively.…”

Recent progress on polyphenylene oxide-based thermoset systems for high-performance copper-clad laminates

“…For conventional polymeric matrices for rigid PCBs, epoxy resin is extremely popular in the low-frequency (<1 GHz) electrical industry [17][18][19], however, it has undesirably high D f ∼ 0.02@1 GHz, as well as inferior thermal stability at high temperatures for lead-free application [18,[20][21][22][23][24][25][26]. Even though the modified epoxy with enhanced performance is being widely investigated, the polar hydroxyl groups in the cured epoxy resins still lead to high dielectric constant (D k ) and D f [27][28][29][30][31][32]. CE has also been well investigated and normally combined with other resins, which possess good dielectric properties (D f ∼ 0.006@1 GHz), heat resistance, and mechanical properties [33][34][35][36][37][38][39][40][41][42][43][44][45][46].…”

Thermally Stable Siloxane Hybrid Matrix with Low Dielectric Loss for Copper-Clad Laminates for High-Frequency Applications

“…10,11 Furthermore, epoxy based nanocomposite and modified glass fabric that can enhance the performances of CCLs have been reported. 12,13 Despite such efforts, the dielectric properties of such epoxy resins are not greatly improved because of the presence of polar hydroxyl groups, which drastically increase the values of Dk and Df in polymeric dielectrics via the curing of the epoxy resins. 14−16 To address this issue, researchers use engineering plastics (e.g., polyimide, poly(p-phenylene ether), bismaleimide, and polytetrafluoroethylene) for HPCCLs.…”

“…Modified epoxy resins (e.g., dicyclopentadiene epoxy), because of their enhanced thermal and dielectric properties with good process ability by introducing dicyclopentadiene (DCPD) groups that have excellent dielectric properties and thermal stability, are currently used as alternatives to conventional epoxy resins. , Furthermore, epoxy based nanocomposite and modified glass fabric that can enhance the performances of CCLs have been reported. , Despite such efforts, the dielectric properties of such epoxy resins are not greatly improved because of the presence of polar hydroxyl groups, which drastically increase the values of Dk and Df in polymeric dielectrics via the curing of the epoxy resins. − …”