Nowadays, die attach glue is widely used in adhesive die bonding packages, for its high heat dissipation ability and good resistance against thermal fatigue. However, because of the fillet and the uncontrolled bond line thickness, bubbles or voids can easily occur in the interfaces between wafer and adhesive layer, which will further lead to delamination or package cracking. In the circumstances, people are thinking to use another new die attach material: die attach film (DAF), to replace the die attach glue in some applications, for its advantages of consistent bond line thickness, no bleeding, no voids and so on....[ Read more ]

Nowadays, die attach glue is widely used in adhesive die bonding packages, for its high heat dissipation ability and good resistance against thermal fatigue. However, because of the fillet and the uncontrolled bond line thickness, bubbles or voids can easily occur in the interfaces between wafer and adhesive layer, which will further lead to delamination or package cracking. In the circumstances, people are thinking to use another new die attach material: die attach film (DAF), to replace the die attach glue in some applications, for its advantages of consistent bond line thickness, no bleeding, no voids and so on.

Although many integrated device manufactures and semiconductor companies are considering the applications of DAF, there are still some potential issues over the employment of this new material, package cracking is the most serious one. Moreover, there are not any selection criteria or guidelines for them to reference or follow. So it is really necessary to set up some selecting criterion of DAF refers to specific issues about its reliability.

In this study, at first the mechanism of package crack in adhesive die bonding packages was studied and seven DAF properties were correlated with package crack resistance. Furthermore, characterization methods and a finite element model for these properties were successfully set up and reasonable results were received. On the basic of these experiment results, a selecting criteria with DAF priorities in different priorities for high package crack resistance was recommended, which could be used as a guideline for electronic package industry to choose a specific DAF with high package crack resistance for some applications.