Silica Filled Resin Viscosity Minimization during High Pressure Lamination Ramps
Silica-filled resin viscosity minimization requires synchronizing heating ramps with press pressure timing to ensure complete void encapsulation without core shift.
High Pressure Lamination
Bonding Process
Fabrication of multi-layer circuit boards utilizes significant mechanical force inside a hydraulic press to fuse copper foils and prepreg layers. Through high pressure lamination the epoxy resin flows into the vacancies around internal circuits to remove air pockets and create a solid structural block. It requires precise synchronization of force and temperature to ensure that the resin cures while maintained under a vacuum.
Void Prevention
Trapped air inside the internal layers expands during subsequent assembly operations and results in catastrophic delamination of the substrate. Constant force prevents the prepreg from moving laterally while the resin is in its liquid state during the middle of the cycle. This method compresses the glass fibers into a dense lattice that supports the electrical characteristics of the finished product.
Proper application depends on the specific rheology of the prepreg material selected by the designer.
Registration Control
Mechanical stability during the press cycle prevents individual cores from shifting away from their intended positions. High force creates enough friction to lock the layers against each other before the chemical cross-linking of the polymer is finalized. This stability ensures that the pads on internal layers align accurately with holes drilled after the pressing is complete.