Electronics Forum: qfp and soldermask (Page 1 of 13)

qfp and soic joint Problem

Electronics Forum | Tue Apr 11 10:30:46 EDT 2000 | Jeremy Smith

I am having a problem with some joints on a 100 pin pqfp and few different soics on one particular board. When viewed a 8x with a "Mantis" inspection scope the joints look as though they wetted to the ic leg but when probed the leg will pop loose.

seperation of soldermask and pcb

Electronics Forum | Tue Mar 25 09:35:28 EDT 2014 | emeto

Have you tried to bake the boards before you process them?

seperation of soldermask and pcb

Electronics Forum | Tue Mar 25 10:31:05 EDT 2014 | sara_pcb

The boards are baked for 2 hours at 120 deg C Regards, R.Saravanan

seperation of soldermask and pcb

Electronics Forum | Tue Mar 25 08:29:33 EDT 2014 | sara_pcb

Please refer the attached jpegs, The problem is noticed after reflow soldering followed by conventional through hole soldering. Flux used one is MIL Std. Brush cleaning in IPA is followed after each soldering step. regards, R.Saravanan

seperation of soldermask and pcb

Electronics Forum | Tue Mar 25 11:25:18 EDT 2014 | horchak

The first impression I get is that the mask was applied over dirty or contaminated copper. What is the trace and land finish on the PCB? You also appear to have a wetting problem.

seperation of soldermask and pcb

Electronics Forum | Tue Mar 25 11:43:48 EDT 2014 | sara_pcb

It is Solder Mask on Bare copper, The land finish is HASL as per MIL-PRF-55110G which accepts trace of HASL as acceptable. Wetting is acceptable. regards, R.Saravanan

seperation of soldermask and pcb

Electronics Forum | Tue Mar 18 11:53:58 EDT 2014 | sara_pcb

Our contract manufacturing agency have procured pcbs from approved vendor. After assembly we found solder mask separated from the PCB on the epoxy area as patches. The top side is intact. also over the pcb tracks, the mask got damaged. In what c

seperation of soldermask and pcb

Electronics Forum | Wed Mar 19 08:38:13 EDT 2014 | davef

I can't picture much of what you're saying, not for nothing, I'm just not connecting. During assembly, solder mask can affected by heat and chemicals. Typically this would be during: * Soldering * Cleaning I will tell you this: Not to defend assem

seperation of soldermask and pcb

Electronics Forum | Tue Mar 25 13:55:05 EDT 2014 | horchak

Ok lets put it this way. If the PCB house used a high quality mask and properly applied it to a properly cleaned surface and properly cured it, then as Dave stated above there are only two things that can destroy it. Excessive heat and overly aggress

Re: qfp and soic joint Problem

Electronics Forum | Mon Apr 17 19:30:27 EDT 2000 | Boca

All of the above is good stuff. To add, I have seen this several times if the assembly is wavesoldered. Heat from the wave can partially reflow the top side SM solder joints and weaken them. To test, check joint strength before wave and then after

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