What is 94V on PCB?
We often see words like 94-VO on the PCB, which are added by the circuit board factory. PCB LAYOUT boards can be distinguished by flame-retardant characteristics, and they can basically be divided into flame resistant PCB (UL94-VO, UL94-V1 grade) and non-flame resistant (UL94-HB grade) substrates. With the rapid development of electronic product technology, there are higher performance requirements for CCL. In recent years, as more attention has been paid to environmental protection issues, a new type of non-bromine-free CCL has been divided into flame-retardant CCL, which can be called "green flame-retardant CCL". PCB design is classified from the performance of CCL, and is divided into general performance CCL, low dielectric constant CCL, high heat resistance CCL (normal board L is above 150 ℃), low thermal expansion coefficient CCL (usually used on package substrates) ) And other types.
As the functions of electronic products are becoming more and more complex, and the requirements for frequency and performance are getting higher and higher. In order to meet the above requirements, PCBs must also take into account the product size. Therefore, almost all of them are developed in the direction of multi-layer boards. Therefore, based on glass fiber cloth Copper foil substrates are currently the mainstream in the market.
According to the different reinforcing materials of the board, it can be divided into: paper base, glass fiber cloth base, composite base (CEM series), multilayer multilayer board base, special material base: ceramics base copper-clad laminates, metal core ( Five categories including Metal Core PCB (MCPCB). According to the different resin adhesives used in the substrate, the common paper-based (using insulating paper as a reinforcing material) CCI includes phenolic resin (XPc, XxxPC, FR-1, FR-2, etc.), epoxy resin ( FE-3), polyester resin and other types. In terms of fiberglass cloth, epoxy resin (FR-4, FR-5) is the most widely used, and there are other special resins (glass fiber cloth, polyamide fiber, non-woven cloth, etc.) as additional materials ) Substrate type, these special resins include: resin (BT), imine resin (PI), diphenylene ether resin (PPO), maleic anhydride imine-styrene resin (MS), polycyanide Acid ester resin, polyolefin resin, etc.
In the manufacture of PCB, the materials are basically composed of copper foil substrate (CCL), copper foil, film and various chemical products. In terms of the proportion of raw material cost, the cost of copper foil substrate is the highest, and with the number of layers The difference is about 50% to 70%. The main components of the copper foil substrate are glass fiber cloth and electrolytic copper foil. The function of glass fiber cloth is to strengthen the hardness, and its material is made of glass fiber yarn with a plain weave method. Electrolytic copper foil is one of the basic materials in the electronics industry. Because the copper foil substrate composed of it is an essential material for PCB, the quality requirements are quite high. It not only requires heat resistance and oxidation resistance, but also requires no needles on the surface. Holes, wrinkles, and laminates must have high peel strength, and they must be able to form printed circuits with general etching methods, and they must not deal with substrate contamination such as particle migration. They are copper processing materials with a higher technical level.
