Electronics Forum | Wed Feb 05 19:43:34 EST 2003 | iman
If by the Powers Ta Be (customer/designer), you can't change the PCB design, negotiate for the PCB fab house, to block the via holes with their (green?) solder mask some customers/designers want to have via holes to be present in the PCB pad, due to
Electronics Forum | Sat May 02 08:48:32 EDT 2009 | davef
You have a board defect. Any moisture and/or organic contaminants trapped by the solder resist during lamination may cause solder mask delamination, blistering and/or adhesion loss during subsequent soldering operations or during extended use.
Electronics Forum | Sat May 02 23:31:06 EDT 2009 | kareal
Thanks davef. The defect always occurred during UHAST reliability, but not find in reflow. The key is that there is tin diffuse to copper trace under solder mask. is it a "normal" board defect and what is the potential risk for device? thanks!
Electronics Forum | Fri May 01 07:22:56 EDT 2009 | kareal
In my project of flip chip PGA production , I found serious delamination in interface of solder mask and first layer copper trace of substrate after UHAST 96hrs( 130C, 85%RH) reliability test. The delamination are always around one type solder bump,
Electronics Forum | Tue Dec 05 22:27:05 EST 2023 | padawanlinuxero
Hello, I am experiencing issues with one of my PCB suppliers. Specifically, I am having trouble with solder shorts occurring on a SOIC8 component, and always in the same pads. Upon inspection with a microscope, I discovered that three of the pads ar
Electronics Forum | Sat May 09 23:05:17 EDT 2009 | kareal
Davef, It seems the tin resist residue on copper trace is root cause of whitish layer. but it could explian why I could not detect tin on fresh unit without UHAST. I have performed X-section and EDS analysis on many fresh units,but no any tin was
Electronics Forum | Sun Mar 07 19:53:38 EST 2004 | praveen
Hello, Voids in BGA can not be eliminated. You can only minimize them by reducing the solder paste volume. Try to bake the plastic BGA's and PCB both as per the standard. Check the PCB at the BGA locations if the via's are masked.Masked via's result
Electronics Forum | Sat Mar 06 02:54:25 EST 2004 | tommy
1)Solder paste selection 2)Reflow profile.Focus on soaking and TAL. 3)Moisture control for BGA. 4)Maybe the BGA solder ball already with void. 5)PCB design.Any via on bga land? 6)Solder masking type. 7)Solder paste volume apply on land. 8)IPC class 3
Electronics Forum | Tue Feb 25 10:32:09 EST 2003 | davef
I don't know the precise scheme, but it goes something like this ... WHAT TO DO * Use the general work instruction that applies to all boards. It goes into dimension and hole checking processes. It talks to visual instection of solder mask, solder
Electronics Forum | Thu Oct 26 10:29:03 EDT 2006 | Mike
First, Voiding under thermal pad is unavoidable(pardon the pun), unless you can find a way to add sufficient amount of solder paste to cover the area, and match that solder volume on your terminal leads. I build HVM qty's of "QFN" components w/ therm
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