The Best Way to View PoP Paste

By propping your component up sideways under a microscope (if you don’t have one with a side-view function), you can get a pretty good view of the paste deposit. There are different theories surrounding the deposit profile and its relationship to ‘performance’, although they are all just theories at the moment. We have worked with pastes that have uniform and non-uniform profiles – pastes from each category have worked well. There are so many other characteristics that impact warpage compensation, it’s probably not fair to judge a paste by its profile. Viewing dipped components from the side does allow you to see roughly how much solder paste was applied, and if the deposit is consistent from sphere to sphere.