Direct attach led soldering by new printable AuSn paste

The attachment of any kind of electronic die is critical for the reliability of the device. In the LED (Light Emitting Diode) case, due to the high current density and the generated heat, we need higher thermal and electrical conductivities of the joining material, otherwise it is not possible to guarantee the optimum life time. The AuSn paste coupled with the screen printing technology that we used in this study allow theoretically answering to both challenges of suitable thermal, electrical parameters and high manufacturing volume needed in the LED industry. The study has shown that the new available product is a good candidate, because it matches the full packaging steps from the screen printing to the reflow of the dies. The design of experiment that we conducted has shown that it should be possible to find a suitable process window for the application.