Reliability

Qualification Requirements

The qualification requirements for Pb-free external lead finish differ for surface-mount device (SMD) or through-hole devices (THD).

For the THDs the primary qualification requirement is to demonstrate forward compatibility with new Pb-free solder pastes (based on SnCuAg). The tests to be performed typically include:

For the SMDs reclassification of the moisture sensitivity level (MSL) at a peak reflow temperature of 260 deg. C is required in addition to solderability validation. The MSL reclassification is performed on the largest die size that is used in the package. The tests to be performed typically include:


Preconditioning

ON Semiconductor adheres to JEDEC standard J-STD-020C for preconditioning requirements for surface mount packages. The JEDEC methodology utilizes a predefined moisture soak followed by three reflow soldering passes to simulate warehouse storage and a customers two-sided board assembly process plus one repair cycle.

The reflow profile used by ON Semiconductor for Pb-free products is shown below. All profile features meet JEDEC standards. One profile feature, Peak/Classification Temperature (Tp), exceeds JEDEC requirements. At ON Semiconductor, all products are reflowed with a peak temperature of 260°C +5/-0 regardless of package size and volume.

Moisture Sensitivity Level (MSL)

Surface Mount Packages are qualified to 260 +5/-0 degrees C which exceeds JEDEC standard J_STD-020C.

The majority of the package MSL ratings will remain unchanged from the current MSL 1 classification.

All packages have an MSL rating of MSL3 or better.

If there is a change in the MSL rating of a package, the customer will be notified and appropriate packing precautions will be taken before any product is shipped by ON Semiconductor (such as dry packing).