Hi Andy, I didn't receive the pictures. Could you try sending them again by replying to this message? Steve ________________________________ From: Andrzej Zielinski <[log in to unmask]> To: [log in to unmask] Sent: Tuesday, November 26, 2013 10:59 AM Subject: Re: [TN] Separation between the BGA sodler ball and pad on the PCB Hi, Have sent pictures to Steve Gregory. For sure this is not HIP as I already went through this issue mid this year. Not sure about nickel fracture. Hopefully we will see more from the pictures. Andy Sent using BlackBerry® -----Original Message----- From: Joyce Koo <[log in to unmask]> Sender: TechNet <[log in to unmask]> Date: Tue, 26 Nov 2013 16:13:12 To: <[log in to unmask]> Reply-To: TechNet E-Mail Forum <[log in to unmask]>, Joyce Koo <[log in to unmask]> Subject: Re: [TN] Separation between the BGA sodler ball and pad on the PCB Hop is my guess. Warpage... Joyce Koo Researcher Materials Interconnect Lab Office: (519) 888-7465 79945 BlackBerry: (226) 220-4760 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman Sent: Tuesday, November 26, 2013 11:11 AM To: [log in to unmask] Subject: Re: [TN] Separation between the BGA sodler ball and pad on the PCB Hi Andy - if you can send the pictures to Steve Gregory, he can post them so we can all view them. What you describe sounds like Head on Pillow or possibly Brittle Nickel Fracture but having the pictures will assist in making an accurate assessment. One action you can take that will be very informative is to run shadow moire on the BGA to measure how much warp happens during the reflow process. Excessive package warp could be the root cause of your issue. Dave Hillman Rockwell Collins [log in to unmask] From: Andrzej Zielinski <[log in to unmask]> To: <[log in to unmask]> Date: 11/26/2013 09:34 AM Subject: [TN] Separation between the BGA sodler ball and pad on the PCB Sent by: TechNet <[log in to unmask]> Dear Colleagues .. I am facing an issue with the BGA part where in three locations we found separation between the BGA solder balls and pads on the PCB (ENIG finish). This condition was discovered during the cross-section that we have requested from our local lab. I can share few pictures I have taken from our report (can't attach the whole document as this report is confidential to our business). Basically this BGA is the plastic ACTEL package 896 pins, SAC305 finish, soldered with leaded process using 62Sn/36Pb/2Ag solder paste. Temperature was slightly elevated to accommodate SAC305 solder finish from the BGA package. The separation condition we have observed was only found in location A1, A16 & T16 which are the corners of the BGA package. As well all 3 separations occurred after the reflow process was completed because there is an evidence of completed inter-metallic fusion. In location A16 & T16 you can see the copper is protruding of the pad but I have been told this is not an issue and cause of the separation. I was considering package or PCB warpage as the cause of this separation or something related to cooling the board after reflow. I asked our lab to measure the height of the solder balls across row A & T and they all deem to be ok. I have asked to check for the phosphorus content as the pad level to see if this is related to black-pad symptom and the phosphorus was measured as 10.3%. So far the board assembly house is adamant their reflow profile is correct. PCB manufacturer is confident with their PCB and pointing to the assembly house. There is a thought about poor sample preparation where the separation issue would be caused by the lab (during cross-section). We are attempting to perform another cross-section on different board but here I am not really sure if this is the right way to go (extra cost). Because I have never seen such a defect, I am not sure what should be the next step to take. Any advice guys ? Andy ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------------------------- This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. 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For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________