Ravinder,

Yes, it's normal for the BGA pads on the PCB to be smaller than the BGA ball diameter - they should be about the size of the BGA package pad so that the formed joint is fairly symmetrical.

The height / diameter after reflow..... it depends. There will be some variation based on how much solder is applied and how heavy the parts is. Maybe someone has some info, but I haven't studied that closely.

Ben

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ravinder Ajmani
Sent: Thursday, December 17, 2015 4:09 PM
To: [log in to unmask]
Subject: EXTERNAL: [TN] BGA attachment to the PCB

Hi Experts,

My question is about the attachment of a BGA package to the PCB.

If the ball diameter is 0.3 mm and ball height is 0.23 mm, then what will be the final diameter and height of the balls after reflow operation.  My understanding is that the balls collapse during soldering operation.

The diameter of the PCB pads is 0.25 mm.  Is it normal to keep the PCB pads smaller than the BGA balls.

Thanks a lot for your help.

Regards

Ravinder Ajmani
HGST, a Western Digital company
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