RTF, reverse treated electrolytic copper foil is a copper foil that has been roughened to varying degrees on both sides. This strengthens the peel strength of both sides of the copper foil, making it easier to use as an intermediate layer for bonding to other materials. Moreover, the different levels of treatment on both sides of the copper foil make it easier to etch the thinner side of the roughened layer. In the process of making a printed circuit board (PCB) panel, the treated side of the copper is applied to the dielectric material. The treated drum side is rougher than the other side, which constitutes a greater adhesion to the dielectric. This is the main advantage over standard electrolytic copper. The matte side does not require any mechanical or chemical treatment prior to the application of photoresist. It is already rough enough to have good laminating resist adhesion. CIVEN can supply RTF electrolytic copper foil with nominal thickness of 12 to 35µm up to 1295mm width.
The high temperature elongation reversed treated electrolytic copper foil is subjected to a precise plating process to control the size of the copper tumors and distribute them evenly. The reversed treated bright surface of the copper foil can significantly reduce the roughness of the copper foil pressed together and provide sufficient peel strength of the copper foil. (See Table 1)
| Classification | Unit | 1/3OZ (12μm) | 1/2OZ (18μm) | 1OZ (35μm) |
| Cu Content | % | min. 99.8 |
| Area Weigth | g/m2 | 107±3 | 153±5 | 283±5 |
| Tensile Strength | R.T.(25℃) | Kg/mm2 | min. 28.0 |
| H.T.(180℃) | min. 15.0 | min. 15.0 | min. 18.0 |
| Elongation | R.T.(25℃) | % | min. 5.0 | min. 6.0 | min. 8.0 |
| H.T.(180℃) | min. 6.0 |
| Roughness | Shiny(Ra) | μm | max. 0.6/4.0 | max. 0.7/5.0 | max. 0.8/6.0 |
| Matte(Rz) | max. 0.6/4.0 | max. 0.7/5.0 | max. 0.8/6.0 |
| Peel Strength | R.T.(23℃) | Kg/cm | min. 1.1 | min. 1.2 | min. 1.5 |
| Degraded rate of HCΦ(18%-1hr/25℃) | % | max. 5.0 |
| Change of color(E-1.0hr/190℃) | % | None |
| Solder Floating 290℃ | Sec. | max. 20 |
| Pinhole | EA | Zero |
| Preperg | ---- | FR-4 |
Note: 1. The Rz value of copper foil gross surface is the test stable value, not a guaranteed value. 2. Peel strength is the standard FR-4 board test value (5 sheets of 7628PP). 3. Quality assurance period is 90 days from the date of receipt. Good bonding strength, direct multi-layer lamination, and good etching performance. It also reduces the potential for short circuit and shortens the process cycle time.
Can be used for high-frequency products and inner laminates, such as 5G base stations and automotive radar and other equipment.