Manual soldering of TQFP 100 pin chips

[karesz]

Hi Azeri,

In my opinion is better a sort/type "special quadrate tip" to have (maybe you can "home-made" it with some tool), than these jet/nozzle is on all side of IC works in same time and so is more efficient, & spares stress for components & board...
These nozzle is optimally cca. 1mm oversized to the measures of IC sizes and is only from a thin metal sheet_ as your round nozzles too...
Otherwise you can with some smaller nozzle (at 3-5mm diameter) make hot the IC pads; guided, in circle, around your chip to (de)solder more times (you must become a fieling for that)...
I have a fine tweezers befor the "action" to hand placed & if check that tinn is molded; rash pick up the IC & clean after that the PCB...
In one case I have desoldered i.e. a 5x5mm 30pin PQFN with normal hot air gun too_thick nozzle on_, but it was a SOS situation & you must be care for not overheating PCB & nearby components_in these case are some neighbor chips light overheated (you can see it on leads optic) on solder pads:I have all resoldered it functions good...
K.

 

[ZackG]

I have had a lot of success soldering SMT chips (80 pin, etc) using toaster oven reflow. The trick is to make sure you have a good solder mask layer on the PCB (I use https://www.4pcb.com to make my boards and have no trouble). Then you use a reflow designed solder, not wire solder. It comes in a syringe which you can squirt out -- ~10^1 micron sized beads suspended in flux. You place the solder using the syringe manually on each pad, or you can stream it across the pads -- the latter sometimes leads to shorts if you use too much solder.

Once the board is loaded with solder, you place the chip on it, put it in the toaster oven and watch it using a flashlight. After a couple minutes, you'll see the solder suddenly melt -- wait a few more seconds for all the flux to burn away, and then turn the oven off and open the door to let the board cool.

Occasionally (especially before you've had practice) you'll have to manually solder a couple pins that didn't get enough solder or got too much (and shorted). When you've got the hang of it it just works.

I recommend using a dedicated toaster -- don't also use it for food!

Piece of cake! I hope this helps.