Soldering complex footprint problems (without paste)

[nuclearcat]

Is it even possible to solder such SIP without stencil?
I tried several times, and in most of cases one of SWD pads (and seems many others) was not connected well. Got SWD once, but then flashing didnt worked (seems elsewhere no soldering joint, maybe on VCC).
(small side pads are 0.4mm x 0.5mm)

This is vendor recommended footprint

SIP in question is named WM-SG-SM-42 (LoRa module, STM32L052 + RF frontend).

P.S. I think for manual assembly (as i dont have precise paste dispenser) better to put via in pads?
Cause i am afraid solder blobs on them lifting up whole package.

[thm_w]

So it comes as shown in the photo? With some solder bumps on the pads already.

Its possible, but I don't know which method is best. With BGA's it seems best to: flux, put a thin layer of solder on the pads, clean, reflux, then place BGA. Of course it has to be relatively even height, maybe its harder with those odd shaped pads. Are you sure the full device is getting hot enough to reflow as well? Leaded solder will be easier.

OwO has posted some photos, but this is no reballing so too much solder for what you are trying to do: https://www.eevblog.com/forum/fpga/cyclone-5-recovered-from-scrap-boards/msg3106784/#msg3106784

[nuclearcat]

So it comes as shown in the photo? With some solder bumps on the pads already.

Its possible, but I don't know which method is best. With BGA's it seems best to: flux, put a thin layer of solder on the pads, clean, reflux, then place BGA. Of course it has to be relatively even height, maybe its harder with those odd shaped pads. Are you sure the full device is getting hot enough to reflow as well? Leaded solder will be easier.

OwO has posted some photos, but this is no reballing so too much solder for what you are trying to do: https://www.eevblog.com/forum/fpga/cyclone-5-recovered-from-scrap-boards/msg3106784/#msg3106784

Yes, lead free solder (damn it). I have oven, but profile is not for lead-free.
Also seems this large pads are culprit. It is very interesting that OwO in that thread applied pressure, it might be good substitute of adding vias in each pad.