Semiconductor Packaging:  DTFS                                    

Deflash/Trim/Form/Singulation (DTFS) consists of the four steps indicated in its name. These steps are defined below.

1.  Deflash - removal of flashes from the package of the newly molded parts..  Flashes are the excess plastic material sticking out of the package edges right after molding.

2.  Trim - cutting of the dambars that short the leads together.

3.  Form - forming of the leads into the correct shape and position. 

4. Singulation - cutting of the tie bars that attach the individual units to the leadframe, resulting in the individual separation of each unit from the leadframe.

Common DTFS-related Failure Mechanisms:

Package Cracking - occurrence of fracture anywhere in the package, often due to excessive mechanical stresses imparted by the DTFS process to the package.

Die Cracking - occurrence of fracture anywhere in the die. In the context of DTFS, die cracking is commonly caused by excessive mechanical stresses imparted by the DTFS process to the package, which may be transmitted to the die.  In some cases, the package will withstand these stresses but the die will not.