Ultrasound Assisted PCB Manufacturing

Hole preparation and metallization are critical processes in the creation of reliable plated through-holes and blind vias. Adhesives used in PCB manufacturing such as acrylic are susceptible to being drawn-out during drilling leaving a type of smear which causes problems on metallisation.

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The function of the desmear process is to remove the residues from the drilling process. It is also designed to create topography or micro-roughening of the resin to improve coating adhesion. Normally the process is achieved by permanganate or plasma treatment.


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Fig 1 - Improved smear weight removal using permanganate with ultrasound


The Susonence project focuses on the improvements which can be gained by the use of ultrasound combined with the permanganate desmear process. Significantly more material can be removed with this technique, reducing the chemical use and the temperature. Consequently large cost savings and environmental benefits can be achieved. 

The use of ultrasound is also being applied to various other materials used in the PCB industry such as polyimide. The use of ultrasound in etching processes can reduce the chemical consumption required.

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