First your pads design is not the same across the 3 points on the PCB, secondly the wire (high AWG) stressed the solder joints. 
Do tag/put adhesive/epoxy to hold the wires on the PCB so that the stress will be hold down at the epoxy area.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Deng RongJun
Sent: Friday, 9 October 2015 4:14 PM
To: [log in to unmask]
Subject: [TN] Solder joint peel off from ENIG board

Hi all:


I have got a solder joint strength issue on ENIG board, the cables soldered on board can be easily detach from pads by a small external force(1kg), the cable mounting process is hand soldering. Failure rate is about 20%.



We have made SEM and EDS test for solder joint and peel off surface, P Wt% is high than normal.  And we have also made SEM test for 10pcs bare board, the Au thickness is 0.038-0.05um, Ni thickness is 2.8-4.0um.



As I know high P Wt% will affect solder joint strength, what issue is happened during PCB fabrication process? Anybody know anything about this?

Here comes pictures:
http://pan.baidu.com/s/1sjl7Ynb

Best regards
Deng

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