Printed circuit boards are divided into two types: organic CCL and inorganic substrates. The commonly used is organic CCL, which contains rigid CCL and flexible CCL. So what are the features of these substrates?
There are several types of rigid CCL materials:
(1) Paper-based CCL, which is divided into two types, one is phenolic resin paper-based CCL, its code is FR-1 in economic performance, flame retardant; FR-2 high electricity, flame retardant, cold punch; XXXPC cold punch ; XPC economical, cold-punching; another epoxy resin paper-based CCL, its code is FR-3 high electrical, flame retardant.
(2)Glass cloth based CCL, known in the pcb manufacturing industry as epoxy glass fiber cloth based CCL. Code FR-4 of high speed drilling, flame retardant; FR-5 flame retardant, of high heat resistance; G10/G11 of high heat resistance, among them FR-4 is the most commonly used variety, the dosage accounts for more than 90% of the total application.
(3) The composite base CCL is divided into two types, one is paper (core) glass cloth (surface), epoxy resin CCL, CEM1 paper base dipped epoxy resin, then double-sided composite glass fiber cloth, and then formed with copper Foil composite hot pressing, flame retardant; the other is glass felt (core) glass cloth (surface), epoxy resin CCL, CEM3 glass felt dipped epoxy resin, then double-sided composite fiberglass cloth, and then formed with Copper foil composite hot pressing, flame retardant.
(4) Metal type CCL is divided into two types, one is metal substrate type CCL, copper plate, steel plate or aluminum plate, epoxy resin prepreg, copper foil are made by hot pressing, in good mechanical properties, and good heat dissipation performance; The other metal core substrate type CCL is made of copper, indium and copper, which is then hot pressed with an epoxy resin prepreg and a copper foil. The CTE is low and the heat dissipation is good.
There are two types of flexible CCL materials:
Polyester film type flexible CCL and polyimide film type flexible CCL, which with bending performance, ultra-thin, can form a three-dimensional circuit board, flame retardant. The inorganic substrate has a ceramic substrate, which are alumina substrate and an ammonium oxide substrate, respectively. The CTE is low, the high temperature resistance and chemical stability are good,but it is brittle, so that it is not suitable to make large size PCB.