Fat vs Slim technology

     In "Post-Moore" era which expresses an empirical trend for miniature devices requirement in the next future. The device integration has an enormous kind of elemental devices which has becoming more and more challenging for different aspects from suppliers to cope with. "More than Moore" can be achieved by integrating different kinds of process, using advanced material or high-end equipments, here come is my study today.

    The traditional under metal metallurgy(UBM) is a fat guy which is easy to be lost control of after reflow. Its pitch requirements need to be over 150um, which means the chipset cannot fit into more transistors into package.  Therefore the transistion copper pillars which is a slim guy which has wear a high heel and can be well controlled in its shape. It has been driven by as its size and pitch can be smaller and fits more space between features.

    You can see why recent generation people is more likely to be slimmer person instead of fat guy, even though some fat guy is cuter, haha!~~