Filled Epoxy Prepreg

General Information

Arlon’s 44N is a high resin content multifunctional (175°C) epoxy prepreg system with a proprietary microdisperse ceramic filler system. 44N is engineered for the filling of clearance holes in thin metal cores such as 0.006″ Copper-invar-Copper or via holes in sequentially laminated MLB designs. Based on Arlon’s 45N, the 44N system is compatible with conventional epoxy lamination and fabrication. Meets requirements of IPC-4101/98.

Detailed Specs

We suggest the use of vacuum or vacuum assist lamination. Pressure, temperature and time may vary depending on the available equipment, panel size and complexity and other factors.

Controlling the heat-up rate, of the multilayer package, to 8-12°F/4-7°C per minute between 150°F and 300°F/65-150°C is recommended. See start point recommendations for pressure in table below:

A 90 minute cure at a temperature of 365°F/185°C should achieve a Tg of >170°C. When the lamination package contains layers of metal core, the cure time may need to be extended to offset the heat lagging effects of the metal.

NOTE: for sequential lamination use 60 minutes for the first lamination and 90 minutes for the final. Cool down under pressure at < 10°F/min (5.5°C/min). Cool down at < 5°F/min (3°C/min) can enhance reliability and resistance to cracking.

  • Drill at 350 SFM. Undercut bits are recommended for vias 0.018” (0.45cm) and smaller De-smear using alkaline permanganate or plasma with settings appropriate for FR-4. slightly longer dwell times may be needed for multifunctional compared with difunctional FR-4.
  • Bake for 1 – 2 hours at 250°F (121°C) prior to solder reflow or HASL.

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