We are going to begin using a 64 pin 10mm QFP with 0.5mm lead pitch. I was recently asked if we need to purchase our PCB with E3 coating instead of tinned pads when using the .5 pitch. The concept being suggested is that the E3 coating will give us better pad flatness necessary for low defect soldering of a .5 pitch.
We do use E3 on some of our products currently.
Since I do not have experience mounting this pitch in the past and will be accountable for my response I didn't want to speak off the cuff. Will it make any difference?
We are currently "on contact" printing on 0.2mm laser cut stencils. We our using RMA paste.