How to choose the PCB board sheet?

Select the PCB material must meet the design requirements and production and cost the middle to strike a balance. The design requirements include these two parts of the electrical and institutions. This material is usually in the design of very high-speed PCB board (greater than GHz frequency) problem would be more important. For example, the now commonly used FR-4 material, when the frequency of several GHz, the dielectric losses (dielectric loss) would signal attenuation has a great influence, and may not be combined. In respect of electrical, pay attention to the permittivity (dielectric constant) and dielectric loss of the suitability of the design frequency.
 94HB: cardboard, do not fire (most low-grade materials, die punching, can not do the power board)
 94V0: flame retardant cardboard (mold punching)
 22F: single-sided glass plate (modulus punching)
 Of CEM-1: single-sided glass plate (must be computer drilling, not punches)
 Of CEM-3: two-sided glass plate (in addition to double-sided cardboard a dual-panel low-end materials, a simple two-panel can use this material, cheaper than FR-4)
 FR-4: double-sided fiberglass board

The classification of the flame retardant characteristics can be divided into 94VO-V-1-V-2-94HB four kinds of
Prepreg: 1080 = 0.0712mm, 2116 = 0.1143mm, 7628 = 0.1778mm
FR4 CEM-3 are expressed sheet, fr4 glass fiberboard, cem3 composite substrate
Halogen-free refers to do not contain halogens (fluorine bromine iodine and other elements) substrate, because bromine is a toxic gas when burned, environmental requirements.
Tg is the glass transition temperature, ie the melting point.
The board must fire does not burn, only to soften at a certain temperature. At this point the temperature is called the glass transition temperature (Tg point), this value is related to the size of the durability of the PCB board.
What is the high Tg PCB circuit board and use the advantages of high Tg PCB
  High Tg printed circuit board when the temperature rises to a certain threshold when the substrate is glassy into the rubbery state, the temperature at this time is called the glass transition temperature (Tg) of the board. In other words, the Tg substrate to maintain the rigidity of the highest temperature (° C). That is the common PCB substrate materials at high temperatures, the continuous generation of softening, deformation, melting and other phenomena, also show a sharp decline in mechanical, electrical characteristics, like this affect the life of the product, general plate of Tg 130 ° C or more, high Tg is generally greater than 170 ° C, the middle-Tg greater than about 150 ° C; usually the Tg ≥ 170 ° C PCB printed circuit board, called the high Tg printed circuit board; the Tg of the substrate to improve the heat resistance of the printed circuit board , moisture resistance, chemical resistance, resistance to stability characteristics will enhance and improve. TG values ​​higher the sheet resistance of the temperature the better the performance, especially in the lead-free process, the application of high Tg; high Tg refers to the high heat resistance. With the rapid development of electronics industry, especially the computer as the representative of electronic products, toward the high function, high multi-storey development, need a higher heat resistance of the PCB substrate material as a prerequisite. The emergence and development of high-density mounting technology SMT CMT, PCB become increasingly dependent on the substrate in the small pore size, fine lines, thin, high heat resistance of the support.
The difference between FR-4 High Tg: at high temperatures, especially under the heat of the moisture after its mechanical strength, dimensional stability, adhesion, water absorption, thermal decomposition, thermal expansion and other kinds of situations are different, the high Tg significantly better than the common PCB substrate materials.
   Bonded Copper knowledge and standards of PCB material is heavily used in China, there are the following types, their characteristics are as follows: a variety of Bonded Copper species, Bonded knowledge, the classification of copper clad board. The general board of reinforcements, can be divided as follows: paper-based, glass fiber cloth, composite base (CEM series), laminated multilayer base and the base of special materials (ceramics, metal core base, etc.) five categories. Resin adhesive board classification, the paper base the CCI. : Various types of phenolic resin (XPc, XxxPC, FR-1, FR-2, etc.), epoxy (FE-3), polyester resin. Common glass fiber Burkina CCL epoxy (FR-4 FR-5), it is currently the most widely used type of glass fiber Burkina Faso. There are also other particularity resin (glass fiber cloth, polyethylene-based amide fiber, non-woven for added material): bismaleimide modified triazine resin (BT), polyimide resin (PI) two phenylene ether resin (PPO), maleic anhydride imide - styrene resin (MS), cyanuric acid ester resin, polyolefin resin, and so on. CCL's flame-retardant performance of classification can be divided into the flame retardant (UL94 the VO, the UL94 one V1 class) and non-flame retardant (UL94, one HB grade), two types of board. Nearly two years, with more emphasis on environmental issues, in a flame retardant CCL CCL varieties of the separation of a new type of non-brominated compounds, can be called "green-type the retardant cCL". With the rapid development of electronic products, cCL have higher performance requirements. Therefore, the performance from the CCL classification is divided into the general performance of CCL, low dielectric constant of CCL, high heat resistance of CCL (General board above 150 ° C), low thermal expansion coefficient of CCL (generally used on the package substrate ) and other types. With the development of electronic technology and continuous improvement on the printed circuit board substrate material continuously put forward new requirements, so as to promote the continuous development of the copper clad board standard. At present, the main criteria of the substrate material below.

1 National standards: national standard for the relevant substrate materials GB/T4721-47221992 and GB4723-4725-1992, China's Taiwan region, the copper clad board standard CNS standards, is developed by Japan JIS standard modeled in 1983 release.
International standard: Japan's JIS standard, the United States of ASTM, NEMA, MIL, IPC, ANSI, UL standards, the United Kingdom Bs Standard, German DIN and VDE standards, French NFC, the UTE standards, Canadian CSA standards, Australia AS standards, the former Soviet Union FOCT standard international IEC standards; PCB design materials suppliers, common and commonly used there: Shengyi \ Jian-tao \
Accept the file: Protel autocad, PowerPCB orcad the gerber or solid board copy board, etc.
Plate types: CEM-1 CEM-3 FR4, high TG materials;
Maximum board size: 600mm * 700mm (24000mil * 27500mil)
Processing board thickness: 0.4mm-4.0mm (15.75mil-157.5mil)
● The highest processing layers: 16Layers,
● copper foil thickness: 0.5-4.0 (oz)
Finished Product Thickness Tolerance: + /-0.1mm (4mil)
Outline Tolerance: computer milling: 0.15mm (6 mil) Punch board: 0.10mm (4mil)
Minimum line width / spacing: 0.1mm (4mil) linewidth control capability: <+ -20%
● Minimum finished drilling Aperture: 0.25mm (10mil)
● product Minimum Hole Size: 0.9mm (35mil)
● Finished aperture Tolerance: PTH: +-0.075mm (3mil)
● NPTH: +-0.05mm (2mil)
Finished hole wall copper thickness: 18-25um (0.71-0.99mil)
● smallest SMT chip spacing: 0.15mm (6 mil)
Surface coating: Immersion gold, HAL, the entire board nickel-plated gold (water / soft gold), screen printing Lan, such as plastic
● board solder mask thickness: 10-30μm (0.4-1.2mil)
● Peel Strength: 1.5N/mm (59N/mil)
● Solder Mask Hardness: 5H
Solder plug hole capacity: 0.3-0.8mm (12mil-30mil)
● dielectric constant: ε = 2.1-10.0
● Insulation resistance: 10KΩ-20MΩ
● Characteristic impedance: 60 ohm ± 10%
● Thermal Shock: 288 ℃, 10 sec
● finished board warpage: <0.7%
● Applications: communications equipment, automotive electronics, instrumentation, global positioning system, computer, MP4, power supplies, appliances and other.