A core is a rigid sheet of cured laminate clad with copper foil on both faces, supplied in fixed thicknesses such as 0.1, 0.2 or 0.36 mm. In multilayer fabrication the inner-layer patterns are imaged and etched onto cores, which are then stacked with prepreg and outer foils and pressed together. Because a core's thickness is tightly controlled and does not flow during lamination, designers like to put their tightest impedance layers against core dielectrics.
Put the high-speed pairs on layer 3 against the core, the prepreg side moves too much in the press.
Also heard as
- inner layer core
- core laminate
Related terms
Prepreg
Glass cloth soaked in partly cured resin, used as the bonding layer that glues cores together in a multilayer board.
Stackup
Ordered arrangement of copper layers, cores and prepregs that makes up a multilayer board, with each thickness.
Laminate
Sheet of reinforced resin, usually clad with copper foil, that rigid printed circuit boards are built from.
Copper weight
Thickness of copper on a board layer, expressed as ounces of copper per square foot.
Same word, different worlds
The central glass region of an optical fiber where the light actually travels.
Concrete & CementA cylinder of hardened concrete drilled out of a structure to test its strength or inspect its condition.
Asphalt PavingA cylinder of pavement drilled out of the finished mat and sent to the lab for density and thickness.
NonwovensTube, usually paperboard, on which nonwoven fabric is wound to make a roll.