A laminate is a composite of woven glass cloth or another reinforcement impregnated with resin and cured under heat and pressure, usually with copper foil bonded to one or both sides (copper-clad laminate). Its glass transition temperature, dielectric constant, loss tangent, thermal expansion and decomposition temperature decide what a board can survive in assembly and how fast signals can run on it. Laminates are specified by family, such as epoxy FR-4, polyimide, PTFE or hydrocarbon ceramic, and by slash sheet number in IPC-4101.
Customer called out a laminate we don't stock, ask if the IPC-4101 /126 equivalent from our usual supplier is acceptable.
Also heard as
- copper-clad laminate
- CCL
- base material
- substrate
Related terms
FR-4
Flame-retardant glass-epoxy laminate grade that is the default base material for rigid circuit boards.
Core
Fully cured laminate with copper on both sides, etched into inner layers and bonded with prepreg into a multilayer.
Prepreg
Glass cloth soaked in partly cured resin, used as the bonding layer that glues cores together in a multilayer board.
Tg
Glass transition temperature: the point where a board's resin turns from rigid to rubbery and expands much faster.