Few cents about the process: hot air soldering station, leaded stain, and some patience.
- Put some solder on the DFN and QFN parts. BGA already have (the balls themselves). This method works for small BGA (48 balls in this SRAM).
- Put some solder on the footprint. Here, an stencil (there are plastic stencils and manual systems to use them) would be useful, but we don't have it.
- Remove the excess of solder from the pads and components.
- Prepare the hot air soldering station with a low speed, medium volume nozzle, about 450ÂºC. In our case, we remove directly the nozzle. This point is important: a high air speed will move the part or even remove little (0603 and such) components if present (literally, blow them away).
- Heat up the board, as even as possible around the component, without the component, and trying to isolate thermally the board to avoid excessive cooling.
- Place the component accurately (the most difficult part, specially for BGA).
- Apply heat again.
- With a little plier or tweezers, move sligtly the component while applying heat, until one can see that the melted solder places the component in position thanks to the surface tension.
- Stop applying heat, wait until the board cools down.
- Aply some 'cold air' or move to another component.
I don't have any video, but could be interesting trying to do one. I will let you know if this happens.