This app note from Texas Instruments covers the basic guidelines on how to solder QFN and SON lead-less package. It includes some PCB design, solder paste screen printing, assembly, and reflow guidelines.
Quad flatpack no leads (QFNs) and small-outline no leads (SONs) are leadless packages with electrical connections made via lands on the bottom side of the component to the surface of the connecting substrate (PCB, ceramic). This application report presents users with introductory information about attaching QFN/SON devices to printed circuit boards (PCBs).
You can see our attempt to solder these chips here.
Via the forum.
We are trying to use TDFN for Watch application. Hence looking out for some more technical info as regards to TDFN soldering guidelines.