Explain the PCB board assembly type in detail

There are many materials used to make pcb circuit boards. FR4 is the most common. What PCB materials are they? Now let's make a classification according to the material classification, different reinforcement materials and different flame retardancy. Let's go to learn more about it.

1、 According to different materials, PCB boards are divided into organic materials and inorganic materials.

Organic materials: phenolic resin, glass fiber/epoxy resin, polyimide, BT/Epoxy, etc.

2. Inorganic materials: such as aluminum, copper invar (non expanding steel) - copper, ceramic, etc., which mainly take its heat dissipation function.

There are also fire-resistant plates: FR-1, FR-2, FR-3 (the above three are paper substrates) and FR-5 (epoxy resin, CEM-1 paper fiber (generally white) are single-layer plates and composite epoxy resin copper foil substrates CEM-2 to 5. The flame-retardant board with fire rating of 94V-0 does not self ignite, and the fire source of 94HB non flame-retardant board will extinguish within about 5 seconds after leaving.

2、 According to the different reinforcement materials of pcb circuit board, it can be divided into five categories: paper base, glass fiber cloth base, composite base (CEM series), multilayer board base and special material base (ceramic, metal core base, etc.). Generally, PCB substrate materials for printed boards can be divided into two categories: rigid substrate materials and flexible substrate materials. In general, copper clad laminate is an important type of rigid substrate materials. It is made of Reinforeing Material, impregnated with resin adhesive, dried, cut and laminated into blanks, covered with copper foil, steel plate as a mold, and formed in a hot press under high temperature and pressure. Generally, the semi solidified sheet used for multilayer board is the semi-finished product of CCL during PCB manufacturing (mostly made of glass cloth soaked with resin and dried).

3、 According to CCL's flame-retardant pcb circuit boards, they can be classified into flame-retardant (UL94V-O, UL94V-1) and non flame-retardant (UL94HB) boards. In recent years, as more attention has been paid to environmental protection, a new type of bromine free CCL has been developed among flame retardant CCLs, which can be called "green flame retardant CCL". With the rapid development of electronic product technology, CCL has higher performance requirements. Therefore, according to the performance classification of CCL, it can be divided into general performance CCL, low dielectric constant CCL, high heat resistance CCL (L of general board is above 150 ℃), low thermal expansion coefficient CCL (generally used on packaging substrate) and other types.