Rheology Testing of Multilayer Prepregs

To meet higher requirements on multilayer PCBs, good control of the prepreg parameters is essential. The standard prepreg tests of gel time and flow are insufficient. New test methods such as melt viscosity, scaled flow test and differential scanning calorimetry give the required information. The test methods are compared for different materials. Rheology testing using a melt viscosimeter is an important tool for both prepreg and PCB manufacturers.