Projects / Programmes
Pulse Curent Source for Plating of Complex Printed Circuit Boards
| Code |
Science |
Field |
Subfield |
| 2.12.00 |
Engineering sciences and technologies |
Electric devices |
|
| Code |
Science |
Field |
| T170 |
Technological sciences |
Electronics |
Pulse Current Source, High density PCB, Multilayer PCB, Microvias, Periodic Pulse Reverse Plating
Researchers (15)
Organisations (2)
Abstract
In the frame of the applied research project, a new topology of a pulse current source for plating of complex printed circuit boards (PCB) is to be investigated. Experimental results of the effect of pulse parameters on laboratory prototypes have shown, that with an appropriate current waveform-shaping, an outstanding improvement in the distribution of copper on the PCB (copper layer thickness on the surface and in the microvias, where the ratio between the PCB thickness and the microvia diameter is very high) can be achieved. This is a characteristic of high density PCB's, multilayer PCB's and connecting panels. Duration of the current pulse can be in the range of just a few microseconds, whereas the amplitudes are compared to DC current procedures several times higher. The pulsed current technology therefore requires amplitudes of several 1000 amperes. In the development phase of the proposed project of a new pulse current source, various topologies that would cover the afore mentioned pulse parameters (maximum current amplitude 300 A and minimum pulse duration time of 50 microseconds) will be investigated. Furthermore, the research work will be focused on a new current regulation principle that beside providing for a better efficiency of the source also enables parallel connection of several power modules. With this solution, pulse parameter setting capability will be improved to the stage where the amplitude of the pulse could be changed even during the current pulse forming, which is not the case with common solutions. A modular approach will provide for an inclusion of several current sources with arbitrary amplitudes into the process of pulse plating, which is of great interest especially in the case of metal plating on extremely asymmetrical surfaces of the PCB's or other objects.
With the proposed modular pulse current source, copper plating of complex PCB's will be tested. Due to a very high dynamics of the pulse current, an optimum space distribution of electrodes in the galvanic bath that would reduce the parasitic inductivities of the load circuit is to be found. During the experiments, a special attention will be paid to the influence of the anode and cathode current in the galvanic bath on the crystallization of copper and on the distribution of copper on the PCB surface and walls of the microvias. Analysis of the copper distribution will be made using well known metalographic methods.
