Copper foil for CCL and PCB can be divided into standard copper foil, high temperature and high elongation copper foil, high elongation copper foil, transfer resistant copper foil and low profile copper foil.
1. Standard copper foil
It is mainly used to press paper-based phenolic resin copper-clad laminate and epoxy resin glass fiber cloth copper-clad laminate. For the copper foil used in paper-based copper clad laminate, in order to improve the bonding strength between copper foil and substrate, a layer of special adhesive should be coated after the copper foil is roughened. The roughening surface roughness of the copper foil is relatively large, and the thickness of the copper foil is generally about 35-70um, and various performance requirements are required It's not very high. For the copper foil used in glass fiber cloth copper clad laminate, in addition to the necessary roughening treatment, but also heat-resistant treatment (such as zinc plating, brass plating, etc.), special high-temperature and anti-oxidation treatment, has a high binding force with the substrate, the heat-resistant temperature is about 200 ℃, it is mainly 18um copper foil.
2. High temperature and high elongation copper foil (the copper foil)
It is mainly used on multi-layer printed boards. Because the heat of multi-layer printed circuit board will cause the copper foil to recrystallize, it is necessary to have the same high elongation at high temperature (180 ℃) as that at normal temperature. Therefore, high-temperature extensible copper foil is needed to ensure that there is no ring crack during the production of printed circuit board.
3. High elongation copper foil (hd)
It is mainly used in flexible circuit board, which requires high bending resistance, so it must have high density and necessary heat treatment process.
4. Transfer resistant copper foil
It is mainly used in printed circuit board with high insulation requirements. If copper ion transfer occurs after copper foil is made into circuit board, the insulation reliability of the substrate will be greatly affected. Therefore, special treatment (such as nickel plating) on the surface of copper foil is necessary to inhibit further ionization and further transfer of copper.