Thick Copper Circuit Board
Thick Copper PCB Manufacturer & Assembly – One-stop service
Printed circuit boards (PCB) are usually coated with thick copper foil on a glass epoxy substrates commonly thickness of copper foil are 18μm, 35μm, 55μm, and 70μm. The most common copper foil is 35μm. The ones we normally used in China is generally 35 to 50μm. Others as thin as 10μm or 18μm; And 70μm thicker than that.
1. Definition of thick copper plate
There is no exact definition of a thick copper plate in the circuit board industry. Generally, the outer layer of finished copper thickness≥ 2oz will be treated as a thick copper plate.
2. Common substrates
FR-4 ， CEM-3 ， CEM-1, 94HB，94VO， polytetrafluoroethylene, polyester 、polyimi。Common substrates are fr-4, cem-3, cem-1, 94HB,94VO, poly tetrachloroethylene, polyacrylamide.
3. Electrical performance
D, The thickness of composite copper foil on l~3mm thick substrate is about 35 μm, the thickness of composite copper foil on substrate smaller than mm thickness is about 18 μm, and the thickness of composite copper foil on 5mm thick substrate is about 55 μm.
If the thickness of copper foil on PCB is 35 μ m and the printed linewidth is 1mm, the resistance of each 10mm is about 5m Ω, and the inductance is about 4nH。When the di/dt of digital integrated circuit chip on PCB is 6mans and the working current is 30mA, the noise voltage produced by each part of the circuit is estimated to be 0.15mV and 24mV. when the resistance and inductance of each 10mm long printed line are estimated to be 0.15mV and 24mV, respectively.
- Improve the uniformity and symmetry of copper coating
- Improve copper residue rate of the inner layer
- Increase line width and line spacing
- Optimize the design of inner layer pad
5. Control processing difficulty
- Etching the difficulty
- Laminated difficulties
- Drilling difficulties
- Difficulty in ink solder resistance
When the copper thickness of the outer layer is 2oz, the thickness of the finished product is≥70um. For silkscreen and solder mask. the ink thickness of line surface and corner cannot be guaranteed by one-time printing, and generally, two times printing is required.
6. Application field
A thick copper plate is mainly used for power supply products, As the conductive layer or inner core heat dissipation layer of the high current substrate, the thick copper plate is characterized by stable performance and better emission of high heat generated by the high current load in the substrate. Therefore, the thick copper plate is widely used in power module, automobile electronic components and base station equipment for network.when the requirement on voltage and current are relatively high.
Lastly, How should we choose the thickness of copper foil for our products?
It mainly depends on the application and voltage& the current magnitude of the signal of our products.