Copper foil for PCBs
1 May 2002
Gould Electronics has unveiled four copper foil products to meet the needs of the printed circuit board industry.
They comprise the TCR foil with integrated thin film resistor, the TCU ultrathin copper foil, the TCC planar capacitor foil, and the LD foil for laser drilling.
TCR thin film resistor foil was developed to meet the increasing challenges of packaging high speed, high density electronic devices. It consists of a resistive metal which is applied to the matte side of Grade 3 reverse treat copper (RTC) foil using roll-to-roll vacuum deposition techniques. The resistive material is also available on other base foils.
TCU ultrathin copper foil was created for high speed circuit boards. Its very low profile structure suits it to applications involving controlled impedance, high frequencies and very fine lines. TCU is a copper carrier foil with a thin copper layer applied using proprietary technology. The copper carrier can be removed even after exposure to temperatures as high as 225 degrees C.
TCC planar capacitor foil consists of a polymeric substrate with a thin metal tiecoat, copper seedcoat and a layer of electrodeposited copper on both sides. The polyimide dielectric is free standing and non-brittle so designers need not be concerned about overlapping etched features and copper on card edge.
LD laser drillable foil is intended for high density circuitry with small microvia interconnects in advanced printed wiring boards. It allows manufacturers using CO2 laser drills to lase less than 100 micron diameter microvias at reduced power thereby avoiding the issues of copper overhang and resin crack defects associated with conventional foils. Cycle times are shortened by eliminating conventional conformal mask process steps for CO2 lasers. LD foil is manufactured by applying a microthin, nickel-based surface treatment to copper foil in a proprietary process. The finished product is a foil with a low reflectivity, energy absorbing surface treatment.
