Die Attach Quality
Die attach failure mechanisms include physical failure of the die bond, physical damage to the die including its surface and adhesive contamination on the die surface.
Shear tests, pull tests and thermal tests are the commonly used tests for die attach process. Drop test and shear tests characterise the bond strength between the die and the package or substrate. Thermal tests characterise bond strength when the sample is put under thermal stress.
Wire Bonding Quality
A wire bond should be strong enough to withstand application specific mechanical and thermal stresses without breaking. Bond strength is an indication of quality and reliability of a wire bond.
Wire pull testing, shear testing, peel testing and thermal testing are commonly used for testing wire bonds. Wire pull tests, peel tests and shear tests determine the strength of bond between the wires and the pads. The thermal testing focuses on testing the bonds under thermal stress.
Encapsulation Quality
The purpose of encapsulation is the protection of die and wire bond assembly, or components on a substrate such as a PCB board. The encapsulation failure mechanisms are usually physical defects in the encapsulation which expose the die/wire bonds to the environment.
Surface profiling and microscopic inspection are typical tests for the encapsulation process. The two tests aim to determine the uniformity of the encapsulation layer and presence of any voids.
