To ensure high reliability and to extract maximum performance from eGaN devices, it is important to follow some simple PCB design and assembly guidelines. In general, the devices must:
1. Have the correct PCB solder mask defined (SMD) footprint for each solder bump to ensure proper containment of solder on a clean PCB surface.
2. Have the correct solder volume and reflow process to provide sufficient height for proper rinsing of any solder flux from between the lands, but not excessive solder, where the joint becomes unstable and tilts or collapses during reflow.
3. Have all flux rinsed from between lands and be dry before applying power.
4. Use of underfill is optional but can significantly improve temperature cycling performance, especially for larger devices. For more details see section six of Reliability Report - Phase 15
The details of these guidelines are presented in Assembling eGaN FETs and Integrated Circuits.
For information on assembly of QFN packages, contact EPC.