Dear All,
ADT is pleased to announce, ADT TW has received the purchase order for 4 X 8030 fully automatic twin dicing machines from one of the biggest OSAT in Taiwan and one of the biggest in the world.
The 8030 dicing saw for this project includes a special cassette compartment and handling system for extracting the two QFN substrates from the Lead Frame magazines and placing the QFN substrates on the cutting chuck. They also include a barcode reader, special dicing and cleaning chucks, and the Height Measuring Tool (HMT) option for accurately measuring the substrate's thickness to enable accurate tapeless shallow cuts.
This unique project will open a new opportunity to lead on the growing Wettable flanks process.
What is Wettable Flanks Process?
Wettable flanks (WF) are modifications to the exposed terminal ends, which "promote solder wetting for the formation of a solder fillet" that is visible. Using a QFN package with a wettable flank enables optical inspection of the soldering, which can increase reliability while reducing cost at the same time.
For QFN packages with multiple I/Os (above 6) and lead-frame thicknesses of 200µm and above, one alternative is to use dimples on the side pads. Dimples are pre-etched, and NiPdAu plated together with the bottom pads by the lead-frame supplier (Costly).
Another alternative (ADT solution) is partial separation of the QFN packages after the molding but prior to tin plating, also known as the "saw plate saw" method. Sawing is performed to a depth that partially exposes the side flank. This means that the pads are still connected by the remaining metal part of the pad flanks ensuring that the continuity of the lead-frame is maintained for the galvanized plating process. Full device separation, with a thinner saw blade, is done after tin plating. Due to the necessary sawing tolerances, this method is — like the dimple's alternative — only suitable for lead-frames greater than 200µm thick.
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