The high-performance organic rigid PCB substrate is usually composed of both a dielectric layer (epoxy resin, glass fiber) and a high-purity conductor (copper foil). We evaluate the relevant parameters of printed circuit board substrate quality, mainly including glass transition temperature Tg, thermal expansion coefficient CTE, thermal decomposition time and decomposition temperature Td of the substrate, electrical properties, PCB water absorption, electromigration CAF, etc.

Generally, substrate materials for printed boards can be divided into two categories: rigid substrate materials and flexible substrate materials. Generally, an important variety of rigid substrate materials is copper clad laminate.

According to PCB board reinforcement materials, it is generally divided into the following types:

1. Phenolic PCB paper substrate

Because this kind of PCB board is composed of paper pulp, wood pulp, etc., it sometimes becomes cardboard, V0 board, flame-retardant board and 94HB, etc. Its main material is wood pulp fiber paper, which is a kind of PCB synthesized by phenolic resin pressure. plate.

Features: Not fireproof, can be punched, low cost, low price, low relative density.

2. Composite PCB substrate

This kind of powder board is also called powder board, with wood pulp fiber paper or cotton pulp fiber paper as reinforcement material, and glass fiber cloth as the surface reinforcement material at the same time. The two materials are made of flame-retardant epoxy resin.

There are single-sided half-glass fiber 22F, CEM-1 and double-sided half-glass fiber board CEM-3, among which CEM-1 and CEM-3 are the most common composite base copper clad laminates.

3. Glass fiber PCB substrate

Sometimes it also becomes epoxy board, glass fiber board, FR4, fiber board, etc. It uses epoxy resin as adhesive and glass fiber cloth as reinforcing material.

Features: The working temperature is high, and it is not affected by the environment. This type of board is often used in double-sided PCBs.

4. Other substrates

In addition to the three frequently seen above, there are also metal substrates and build-up multi-layer boards (BUM).

Substrate material technology and production have gone through half a century of development, and the world’s annual output has reached 290 million square meters. This development has been driven by the innovation and development of electronic products, semiconductor manufacturing technology, electronic mounting technology, and printed circuit board technology. Driven by.