Calculating Layer Registration Drift Budgets for High Layer Count Multilayers
Layer registration drift budgets require RSS vector stacking of material shrink, tooling clearance, and drill wander to protect inner layer annular rings.
Lamination Press
Thermal Compression
High-pressure hydraulic machinery utilizing controlled heating and cooling cycles fuses individual circuit layers into a single multi-layer substrate. In board fabrication, a lamination press applies uniform heat and mechanical force to stackups of prepreg and copper foils. This process liquifies and then cures the resin, bonding the distinct layers together permanently.
Pressure Distribution
Precision hydraulic cylinders and heavy steel platens apply equal pressure across the entire surface of the panel stack to prevent thickness variations. The press uses heated platens or induction heating to raise the temperature of the layup, allowing the epoxy resin to flow and fill all voids around the internal copper patterns. Vacuum systems extract trapped air and volatile gases during this flow phase to eliminate internal voids and delamination defects.
After the cure cycle, the press circulates coolant through the platens to reduce the temperature gradually, minimizing the formation of internal stresses.
Mechanical Structure
Multilayup fixtures hold several panels separated by steel plates to maximize production throughput during a single run. These fixtures must be designed to distribute both pressure and temperature evenly across each layer in the stack. Inconsistent heating or pressure across the platens leads to thickness variations, which can cause drill bit breakage and impedance anomalies.