Additive ProcessAPT's Focussed Field Deposition (FFD) is size and throughput scalable. FFD produces bulk metal copper conductors via an ultra high current density (250A/dm2) bathless and environmentally benign electroplating system where elements within specification need not be interconnected.
In a basic/traditional plating bath, it is often found that the current density, which determines the rate of copper deposition, is not constant over the full area of the substrate being plated. There are several potential sources of varying current density leading to thickness variation. These include, either alone or in combination:
- resistive substrate causing voltage drop which increases with distance from the cathode connection point(s)
- geometry of the plating tank causing variation in the current field pattern
- curvature of the anode and/or cathode surface
- mechanical tolerances in the plating system
For many applications it is desired to maintain plating thickness within controlled limits. For example, this may be because a particular resistance is needed for correct circuit performance (e.g., controlled heating, solar) or because a downstream process, such as chemical mechanical planarisation/polishing (CMP), depends on a uniform covering of copper, or simply for optimum use of raw materials.
Instead of using a single anode, the APT system uses many individually controlled anode segments. The system is able to measure, in real time, the current supplied by each of the anode segments and adjust the plating waveform of each individual segment to equalise the effective current density across the workpiece. These corrections can be varied with time to react to changing characteristics. For example, the voltage drop in a resistive substrate may change as plating proceeds.
Even if thickness variation is not of direct concern, APT’s high volume segmented anode system has the potential for throughput improvement since the average current density over the workpiece can be maintained closer to the optimum value for maximum throughput.
The main features of this technology are:
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Single and multi-layer copper conductors and circuits, reel-to-reel, one metre wide × length of reel of substrate (>1,000 metres). An APT selective FFD system can be built to produce conductor circuits two+ metres wide. Wide sheet system under development.
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Zero waste deposition of copper conductors onto substrates including polymers, metals as well as epoxy-glass materials; even paper.
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Conductors and circuits with passive components (resistors, capacitors and inductors) embedded as part of the production process.
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Sculptured circuits, i.e., adjustable conductor depth; progressively thinner/thicker deposition along independent conductors on the same circuit/pattern and on any portion, on demand at no additional cost, regulated automatically by the system based on design input.
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System speed nominally 5 metres/min single layer, scalable for higher speeds and/or thicker depositions.
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Designed for fast response to support just-in-time, digitally based fabrication of conductors for myriad applications in mass-produced ultra-large volumes and one-off on-demand rapid prototyping; all at no additional cost and all on the same highly flexible system.