High Tg PCB (printed circuit board) is a type of PCBs. In the case of PCB selection as substrate board, FR4 epoxy fiberglass wiki board is used for electrical applications, polyimide fiberglass wiki board is used for high ambient temperature or flexible circuit board, and polytetrafluoroethylene fiberglass wiki board is used for high-frequency circuit. Due to the high-temperature requirements of electrical wiring, metal substrate should be used.
Factors to consider when choosing PCB materials:
· Substrates with high glass temperature change (Tg) should be selected appropriately.
· a low coefficient of thermal expansion (CTE) is required. Due to the oil incompatibility to increase the coefficient of X, Y and the thickness of the lead, it is easy to cause PCB deformation, which causes cracks in the metal hole and damage to the components.
· Extreme heat is required. PCB is usually required to have a temperature of 250 ℃ / 50S.
· Good balance is needed.
Advantages of using high Tg PCB materials:
· First, CAMTECH PCB high Tg means high temperature with the rapid development of the electronics industry, especially electronic devices represented by computers, to the development of high-quality and high-volume multi-layer, high-temperature PCB substrate materials are required as an important guarantee.
· With the emergence and growth of high density insertion technology represented by SMT and CMT, PCB increases and is not separated from the support of high temperature substrate in sections of small opening, fine wiring and narrow types.
· PCB substrates materials under high temperatures, not only producing softness, deformation, melting and other phenomena, but also manifestations in electrical, mechanical properties of sharp penetration (I think we do not want to see their own products reflected in this issue).
· So, the difference between general fr-4 and high Tg fr-4 is that under low-temperature conditions, especially under heat after hygroscopicity, electrical energy, dimensional stability, adhesion, water intake, oil loss, temperature increase and increase. Some conditions are different, and high Tg products are clearly better than conventional PCB substrate materials.
High Tg PCB description:
High Tg refers to extreme heat. Typically, Tg boards exceed 130 degrees, high Tg usually exceeds 170 degrees, and intermediate Tg is approximately more than 150 degrees. Generally, printed PCB boards with Tg≥170 ℃ are called printed boards mounted Tg. With the rapid development of the electronics industry, especially electronic devices represented by computers, to the development of high-quality and high-volume multi-layer, high-temperature PCB substrate materials are required as an important guarantee. With the emergence and growth of high-density insertion technology represented by SMT and CMT, the PCB expands and is indistinguishable from the thermal support of the substrate in small internal aperture, fine wiring, and narrow types.
With the development of Tg of the substrate, heat resistance, moisture resistance, chemical resistance, and PCB stability will be improved. The higher the TG value, the better the resistance of the plate, especially in the lead-free system, and the higher the TG application.
Therefore, the difference between general fr-4 and high Tg fr-4 is that the lower the temperature, especially the lower temperature after hygroscopicity, the mechanical strength, dimensional stability, adhesion, water absorption, heat dissipation, temperature increase, and other conditions. The materials are different, and high Tg pcb products are clearly better than conventional PCB substrate materials.
High frequency Tg PCB method selection:
· Tg value refers to the conversion temperature of the CORE glass, which you can understand as softening the temperature of the dish.
· For manufacturers, the choice of Tg value of PCB depends on the operating temperature or the weather conditions of the PCB products involved. Here we must first talk about the common Tg culture:
· 135 ~ 140 ℃, which is Tg value of common fr-4 plates;
· At about 170 ° c, this is the value of Tg plate in fr-4 high-temperature ladder section;
· About 260 ℃, which is the Tg value of polyimide materials;
Depending on the temperature of the various materials above, they can be distributed on the seat. If some experienced manufacturers consider a temperature of about 40 °, such as a temperature of about 100 °, they can consider a Tg plate of 134-140 °. If it is a safe product (24 hours continuous trouble-free service problem), consider raising the gradient of choice.
High Tg PCB, consisting of the substrate and cover over the substrate, copper-coated, characteristic: the substrate consists of a medium glass fiber cloth and fixed in the middle of the glass curtain on all sides hot plasticity resin mixed plate, hot plasticity resin mixed plate and medium glass fiber cloth fabric with flame retardant mixed plate.