Detailed parameters and uses are as follows:
94HB: ordinary cardboard, not fireproof (the lowest material, die-cutting, not power board)
94V0: Flame Retardant Cardboard (Stamping)
22F: Single-sided semi-glass fiber board (stamping)
CEM- 1: Single-sided glass fiber board (computer drilling is required, and punching with a die is not required).
CEM-3: Double-sided semi-glass fiber board (except for double-sided cardboard, it belongs to the bottom material of double-sided board, and this material can be used as a simple double-sided board, which is 5~ 10 yuan/square meter cheaper than FR-4).
FR-4: The flame retardancy of double-sided glass fiber board can be divided into four kinds of prepregs: 94VO-V-1-V-2-94HB:1080 = 0.0712mm, 2116 =.
FR4 is a glass fiber board and CEM-3 is a composite substrate. Halogen-free refers to the substrate without halogen (fluorine, bromine, iodine and other elements), because bromine will produce toxic gases when burning, which needs environmental protection. Tg is the glass transition temperature, that is, the melting point. The circuit board must be flame-retardant and cannot burn at a certain temperature, but can only be softened. The temperature point at this time is called glass transition temperature (Tg point), which is related to the dimensional durability of PCB.
What is high Tg? PCB circuit board and advantages of using high Tg PCB When the temperature of high Tg PCB rises to a certain threshold, the substrate will change from "glass state" to "rubber state", and the temperature at this time is called the glass transition temperature (Tg) of the board. That is, Tg is the highest temperature (℃) at which the substrate remains rigid. That is to say, the common PCB substrate materials are constantly softened, deformed and melted at high temperature, and at the same time, the mechanical and electrical characteristics drop sharply, which affects the service life of products. Generally, the board with Tg above 130℃ has high Tg above 170℃ and medium Tg around 150℃. Generally, PCB printed boards with Tg≥ 170℃ are called high Tg printed boards; With the increase of Tg of the substrate, the heat resistance, moisture resistance, chemical resistance, stability and other characteristics of printed boards will be improved and improved. The higher the Tg value, the better the temperature resistance of the plate, especially in the lead-free process, high TG is widely used; High Tg means high heat resistance. With the rapid development of electronic industry, especially the electronic products represented by computers are developing to high functions and high layers, which requires PCB substrate materials to have higher heat resistance as a prerequisite. With the emergence and development of high-density mounting technology represented by SMT and CMT, PCB relies more and more on the support of high heat resistance of the substrate in terms of small aperture, fine wiring and thinning. Therefore, the difference between general FR-4 and high Tg is that the mechanical strength, dimensional stability, adhesion, water absorption, thermal decomposition, thermal expansion and other conditions of FR-4 are different at high temperature, especially after moisture absorption and heating, high Tg products are obviously superior to ordinary PCB substrate materials.
PCB knowledge and standards There are several types of copper clad laminate widely used in China at present, and their characteristics are: types of copper clad laminate, knowledge of copper clad laminate, and various classification methods of copper clad laminate.
Generally speaking, according to the difference of plate reinforcement materials, it can be divided into five categories: paper base, glass fiber cloth base, composite base (CEM series), laminated multi-layer board base and special material base (ceramics, metal core base, etc.). ).
If classified according to the different resin binders used in paperboard, paper CCI is common. There are: phenolic resin (XPc, XxxPC, FR- 1, FR-2, etc. ), epoxy resin (FE-3), polyester resin and other types. Common glass fiber cloth CCL includes epoxy resin (FR-4, FR-5), which is the most widely used glass fiber cloth at present. In addition, there are other special resins (glass fiber cloth, polyamide fiber, non-woven fabric, etc. ): Bismaleimide modified triazine resin (BT), polyimide resin (PI), diphenyl ether resin (PPO), maleic anhydride imine-styrene resin (MS), polycyanate resin, polyolefin resin, etc. According to the flame retardancy of copper clad laminate, it can be divided into two types: flame retardant (UL94-VO, UL94-V 1) and non-flame retardant (UL94-HB). In recent 12 years, with people's increasing attention to environmental protection, a new type of bromine-free copper clad laminate was separated from the flame-retardant copper clad laminate, which was called "green flame-retardant copper clad laminate". With the rapid development of electronic product technology, higher requirements are put forward for the performance of copper clad laminate. Therefore, according to the performance classification of copper clad laminate, it can be divided into three types: copper clad laminate with general performance, copper clad laminate with low dielectric constant, copper clad laminate with high heat resistance (L of general board is above 150℃), copper clad laminate with low thermal expansion coefficient (generally used on packaging substrates) and so on. With the development and continuous progress of electronic technology, new requirements are constantly put forward for PCB substrate materials, which promotes the continuous development of copper clad laminate standards.
At present, the main standards of substrate materials are as follows. ① National standards: China's national standards for substrate materials include GB/T 4721-47221992 and GB 4723-4725-1992. The standard of copper clad laminate in Taiwan Province Province of China is CNS standard, which is based on Japanese JIs standard and published in 1983. Ggfggdgeeejjj ② international standards: Japanese JIS standard, American ASTM, NEMA, MIL, IPc, ANSI and UL standard, British Bs standard, German DIN and VDE standard, French NFC and UTE standard, Canadian CSA standard, Australian AS standard, former Soviet FOCT standard, international IEC standard, etc.