Detailed Analysis of Conductive Die Attach Film in Miniature Package X3DFN

Epoxy dispensing die attach method has been the standard in die attach process for many years. However, driven by desire of consumers to have smaller, lighter, and cheaper products, die shrinkage is inevitable. X3DFN packages have die size of 0.20 x 0.20 mm with thickness of less than 3 mils. Epoxy dispensing method has proven to be impractical for these packages due to physical limitation such as inaccuracy in dispensing epoxy and epoxy creep. Industry has come out with another approach which is to coat/laminate a layer of die attach material before wafer saw process. This approach can be done with two different materials which are wafer back coating (WBC) and die attach film (DAF). This paper presents the detailed analysis and comparison between WBC and new generation thermal and electrical DAF.