Thin die - Novel process for stack die packages and yield optimization

Stacking dice using die attach films is a very common approach to pack more and more memory and functionalities into the same foot print area. Devices with up to eight 35 μm thick electronic components stacked using 30 μm thick die attach materials are in mass production today. The next generation devices target die thicknesses of 25 μm and even 15 μm to be stacked using 5 μm thick adhesive layers. Picking and placing these types of ultra thin dies from the wafer mounting tape is extremely difficult. There are 3 areas to explore in order to improve the die bonding productivity for these ultra thin die. The equipment design, the method of picking, and the process used for placing the die. In this contribution a novel die bonder which picks and places a die in parallel allowing for reduction in the overall cycle time is discussed. The die attach process is investigated in detail and methods to improve throughput while maintaining quality are presented.