BGA Secondary Reflow & Ball Separation

Secondary Reflow & How BGA Balls Separate

Here is a video clip I have wanted to make for some time as I have helped customers with this issue on many occasions over the years. Basically, our video shows reflow at the top of the joints and then part separation. The sample was rough ground to a midpoint on the samples then heated from both sides with the aim of showing the separation. There are of course a number of reasons this can happen in wave, selective, rework or on double sided assembly. The problem is they may be intermittent during the life of the product and difficult to find. This is one of my Defect of the Month videos, over 100 titiles created to illustrate the reason for process failures in production or the field. These are all featured on this YouTube page

Basically I did a standard lead free BGA reflow simulation with a little more heat to the top of the component to get reflow starting at the package interface. I have done the same on the board side but not what I wanted to show

This type of experiment was conducted by other engineers in their case they also measured the movement of the balls and package in a detailed study. A little out of my equipment capability and time budget

If I shoot these again I will spend a little more time and decrease the grit size in the paper used but I did want the uneven surface to make it easier to see the change in state of the solder due to the reflection of light. The next experiments are on Low Temperature Solder Joints

[gianni]

This is such a cool shot of the reflow process. Thanks Bob

[ivanreynoso]

Super cool video. Im working on something similar

[NicksStuff]

What a cool video!
Would it be solved by heating the board a little bit longer or do you have to reball?

[kusobatto]

Hello!
Thank you very much for providing this video.
May I ask you the facility you used to take this video?

What exactly is this? Trying to reflow a chip without removing and reballing it?

[jessstuart]

Is this due to the pcb or component substrate flexing while heating?

[Davpana]

I'm an old time hobbist tinkerer, what i want to know, it's not so clear, if this is the second step in board production, the joint between previously balled chip and the pcb.. i would like to know how old were the balls when done this experiment, and if balls was sure good and previously sealed in tight containers before applied to chip.. thanks, bye..