Performance of a hybrid fine pitch quad flat package mounted with a new flux on printed circuit board in surface insulation resistance test

An innovative hybrid quad flat package is designed recently by incorporating two types of leads with two distinctive shapes: gull wing and J-lead. These leads are separated into two layers to increase the adjacent space between them. Pure tin is used as the connector finish in the package, while Sn-3.0 Ag-0.5Cu solder material with a new flux is printed on the footprint copper pads of printed circuit board to join the hybrid packages on it. As compared to the conventional quad flat package, the design significantly increases the lead count by 50 % and reduces the distance between two types of leads to 0.325 mm, consequently improving the functional capability in a smaller size product. Surface insulation resistance test is conducted according to IPC-TM-650 standard to analyse the reliability of the newly designed hybrid quad flat package. The absence of tin whisker and dendrite after the test demonstrates the reliability of this hybrid package product and the new flux applied.