Multi layer blanks consist of two outer layers and a number of cores (two layers per core). An eight-layer board comprises three cores and two outer layers. The cores are aligned and bonded into a panel ready for drilling. The production of the bonded blank is the function of this department.
Checked core material is automatically loaded onto a chemical cleaning line where the surface copper is prepared for the application of a photosensitive chemical resistant layer. The cleaned layer passes on a conveyor into a positive pressure clean room where a photo polymer is simultaneously auto-laminated to both surfaces.
Using precision photo tools mounted in glass to glass printing frames the cores are exposed with the appropriate image.
The exposed core is transferred to a conveyor line where it is developed, etched and stripped. Fiducial alignment sites are used to punch registration holes into the core. These holes will be used to maintain layer to layer registration during the bonding process.
These cores are then 100% checked to Net List. The checking takes place on two A.O.I. (Automatic Optical Inspection) machines that look for microscopic shorts and opens while ensuring that the integrity of the net list is maintained.
The copper surfaces of the cores are then treated to promote bond adhesion. The layers and prepregs are assembled in registration with each other.
Bonding takes place in one of our vacuum assisted presses. Our expert knowledge system stores a library of press cycles that have been developed to ensure that different builds are correctly bonded and within tolerance to specified thickness. Bonded blanks are 100% checked for thickness before further processing.
