Dear all,
I am struggling to successfully solder this incredible tiny part on my prototype with my scarce lab possibilities.
Well, soldering is rather overrated, then the biggest problem is how to place the ic on the pcb.
Please do not start laughing... I think, you know the procedure:
You have this nice strip with the bright silver chips inside, you open the strip carefully and you take one ic out of it. Better said, the chip springs out and if you are lucky, you can find it on you very clean table.
Then you take your twizzers, the finest ones, and grab the ic. No doubt, the thing lays with the bumps upside. So, you want to turn it. This is the moment, where the ic starts jumping around, like a flea...
Suppose, the thing landet on another clean spot of your table, and this time with the bumps downside, now you have to find the mark for bump 1... this nice dark point... but the surface is silver, and is reflective, so if your microscope has lights, you only see black. A light source from the side must be, oh, yes! And there is the point (at least, I think so) But the chip must be turned 90 degrees, in order to be placed correctly. Yes, you guess perfectly good: there is it again, the flea-jump.
By the time you have it again and found the point, (either on the first chip you grabbed out of the strip, or on the third, because the flea flew away of your table), you grab it with the twizzer and transport it to the right place, the solder paste is dry and the chip wont stick to it anymore. If it doesn't stick, the reflow-oven will blow it out of the position (I had this experience too).
This, if you have such a steady hand, that you succeed on placing the flea on the right spot. The chance, that you don't is inmensely bigger, And, off course, you take with you (or the ic does) some of the paste with and you need to start everything again.
Vacuum, that's it, yes, I need vacuum!
But... the tips are all too big.
So, I made a tiny tip and succeeded to grab the chip out of the strip (avoiding flea-jumping, laying on the table looking to the ceiling, etc etc.)
And there is it, the right spot, Now stop the vacuum, let the chip go down, give a nice tick to fix it, Yeah!... yes?... hmmm... no, the chip is not there, but still on the vacuum-tip... Or is down, but on the side...
Aaaaaaahhhhhhh!!!!!!!!!!
Now, if you do not know this, is because you have the correct tools and technic to do it.
Please, please, tell me how you do it !!!
With my best regards,
and also greetings from all the fleas on the ground of my lab...
Gustavo
