Copper Foil with Steel Carrier

ACF2-STEEL: This product is comprised of one piece of copper foil and one panel of steel. It is designed as a carrier sheet for the top or bottom copper layer in an MLB stackup. The copper sheet is attached to the steel carrier with an inert adhesive. The steel separator is plated, providing excellent corrosion resistance.

ACF3-STEEL: This product is comprised of two pieces of copper foil and one panel of steel. It can be used as the top and bottom copper layers on a multiple MLB stackup.

What is Image Transfer?

Image transfer is a condition that refers to an outer-layer of a circuit board displaying the image of the adjacent circuit layer, coming out of lamination. This condition causes uneven topography on the copper surface, which could result in poor-dry-film adhesion, and uneven plating. These defects can lead to increased scrap and poor yields related to shorts. One of the root causes of image transfer is heavier copper traces. ACF addresses this issue by utilizing hardened steel separators.

Our ACF- STEEL can be used as the top or bottom copper layer in an MLB stackup.


Copper Foil
ACF is available with different copper foil types:

  • Standard copper, HTE (IPC Grade-3) for conventional FR-4 circuit boards
  • High bond strength copper, for BT and Polyimide
  • And Very Low Profile copper, for advanced HSLL applications

ACF is available in different copper foil thicknesses:

9 µm 0.25 oz
12 µm 0.375 oz
18 µm 0.5 oz
35 µm 1.0 oz
70 µm 2.0 oz

ACF Steel is available as follows:

Hardness RW-73/DR-8
ASTM A623 Scale 30T
Yield Strength 550
.0063" 0.16 mm

ACF is built with an "inert adhesive" that becomes weaker with heat. After the lamination cycle, the aluminum or poly separators are easily broken-down.

Panel Sizes
Panels are available in sizes 12" x 18" through 25" x 43".

Tooling Configuration
All panel sizes are available with standard multi-line tooling (0.188" offset in short dimension). Other configurations are available on special order basis.