Re: " My request for the root cause on this came down to 2 things. First, the operators were not keeping an eye on things like they should have, Training issue. Second, the inspection before shipping was either blind or not paying attention to what they were shipping, again, training."
/QE neighborly nitpicking/
Neither of those being root cause. Process and equipment design and foolproofing...
Operators and inspectors, valuable control points both. Even on the best day no better than 85% good at detecting a problem.
-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Decker, Scott Collins
Sent: Thursday, May 9, 2019 12:21 PM
To: [log in to unmask]
Subject: [EXT] Re: [TN] Bad Vias - Need help determining the root cause
All,
Although I don't really have a response to this issue directly, I'd like to mention an issue I had about 15 years ago right here in the Tech Net Forum. It too was about a FAB issue I had and how the forum helped me get to the bottom of the problem.
Back at a company I worked at where I was the only PCB Designer, I also happened to be the guy to inspect all the incoming bare boards, (who else would know what to look for than the guy that designed it, right? Also, there were other issues that led me to this new task.). Anyway, I had received some boards with perfect little circular cutouts in the traces, vias, and pads and all randomly located on both the top and bottom side of the boards. I posed the question on the forum about this as Christopher did originally for the issues he has. I waited about a day and a half and I got one reply back from a QA person. After a few back and fourths about the issue, all traffic over Tech Net from him stopped. Later that day I got a phone call from a QA guy at a FAB shop, who asked if I had been communicating with someone via Tech Net about a board issue. When I said yes, he said OMG, those are our boards you have been talking about! So, after a few minutes of picking up jaw bone parts, he told me they had, had a problem with the agitators in the etching tanks that led to bubbles sticking to the boards. These bubbles created the nice round cuts in the copper and they had operators that were not paying attention to the tanks. My request for the root cause on this came down to 2 things. First, the operators were not keeping an eye on things like they should have, Training issue. Second, the inspection before shipping was either blind or not paying attention to what they were shipping, again, training.
When he first called me, he had just left a meeting with management and telling them how lucky they were that I hadn't used the FAB shops name in my posts and what that could have done for their reputation, etc. I stopped using them, he left and we got credit for the boards in the form of "on your next order"... Really... :-/ Anyway, my point is this forum is the place to be for these things and I applaud all those that reply and provide information and share knowledge. With forums like this, it becomes a smaller world and knowledge creates the power move forward.
(Stepping off my Story telling podium now.)
Have a great day and let us know what you find out...
Scott Decker | Senior Engineer, PCB Design Services CID+ | Electronic Systems Center COLLINS AEROSPACE
3445 S. 5th Street, Suite 170, Phoenix, AZ 85040 U.S.A.
Tel: 602 308 5957 FAX: 602 243 2347
[log in to unmask] www.collinsaerospace.com
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-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D
Sent: Thursday, May 9, 2019 10:33 AM
To: [log in to unmask]
Subject: [External] Re: [TN] Bad Vias - Need help determining the root cause
Agreed, Dwight. All good points. And request coupons.
-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Dwight Mattix
Sent: Thursday, May 9, 2019 10:40 AM
To: [log in to unmask]
Subject: Re: [TN] Bad Vias - Need help determining the root cause
And maybe pay for basic QC measures this time -- like 100% netlist opens/shorts testing, x-section solder floats and analysis.
-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Yuan-chia Joyce Koo
Sent: Thursday, May 9, 2019 3:39 AM
To: [log in to unmask]
Subject: [EXT] Re: [TN] Bad Vias - Need help determining the root cause
agree. it could be improper de-smear as well that could cause poor wetting. If I were OP,I'll start looking for alternative board house
- 4 layer capability should not be that hard to find in TX. IMHO.
jk
On May 9, 2019, at 5:51 AM, Gerry Gagnon wrote:
> Dwight,
>
> Sorry to hijack your response but I had an elderly moment with this
> keyboard on my phone. 😬😬
>
> My first vote is for poor electroless copper coverage. Could be due to
> air bubbles as electroless does use air. Could also be that
> electroless did not “take” due to poor hole clean and pre- electroless
> hole prep.
>
> No electroless, no electroplating.
>
> Another possibility could be HASL which typically uses HBR as a flux
> or pre-flux prep before the solder application. A few extra “shots”
> through HASL process in order to meet solder thickness specs could
> take out thin-to-no copper.
>
> Thanks and Best regards,
>
> Gerry Gagnon
>
>> On May 8, 2019, at 8:39 PM, Dwight Mattix <[log in to unmask]>
>> wrote:
>>
>> <<The manager says "in the pattern
>> plating tank we have no air. >>
>>
>> /facepalm/
>>
>> I'd have asked him "Do you even lift, errr... plate bro?"
>>
>> Dielectric reacts with plating solution and outgasses. So it's not
>> just a matter of wetting the hole. It's a matter of continuously
>> egressing the gas out of the hole.
>>
>> -----Original Message-----
>> From: TechNet <[log in to unmask]> On Behalf Of Robert Kondner
>> Sent: Wednesday, May 8, 2019 5:12 PM
>> To: [log in to unmask]
>> Subject: [EXT] Re: [TN] Bad Vias - Need help determining the root
>> cause
>>
>> Be sure to let us know what you find. Enquiring Minds want to Know.
>>
>> Thanks,
>> Bob K.
>>
>> -----Original Message-----
>> From: TechNet <[log in to unmask]> On Behalf Of Christopher Brand
>> Sent: Wednesday, May 8, 2019 7:45 PM
>> To: [log in to unmask]
>> Subject: Re: [TN] Bad Vias - Need help determining the root cause
>>
>> Hi Richard, Victor, Dennis and All,
>>
>> I greatly appreciate all the help and insight so far on this.
>>
>> The boards don't have any selective or wave soldering, just reflow
>> and hand soldering for a few thru-hole connectors. The boards are
>> HASL. The sample of boards in the photos are mostly 2 sided and one
>> that is 4 layer. These are small production runs usually.
>>
>> In talking with the manager of the board shop, he's sending out
>> samples of their plating tanks to be tested. I've asked him the
>> following questions from input from you folks:
>>
>> * Air bubbles in the plating tank? The manager says "in the pattern
>> plating tank we have no air. solution was eductors moving the
>> solution and swishing of the panels during plating".
>> * Is their plating current is sufficient? The manager says that they
>> are "plating the top of the cu scale to be sure". Is there a
>> method
>> I can tell them to check if their plating current is good?
>> * They do have a copy of IPC-9121
>>
>> I am going to look into sending out to get some of the vias
>> microsectioned to get a better look inside them.
>>
>> Is there anything else I need/should be asking them to check?
>>
>> Thank you kindly,
>>
>> Christopher Brand
>> Ludlum Measurements, Inc.
>> 501 Oak Street
>> Sweetwater, TX 79556 USA
>> (325) 235-5494 Phone, ext:3318
>>
>>> On 5/8/2019 9:07 AM, Stadem, Richard D wrote:
>>> Christopher,
>>> Having a little more time to look at your pictures this morning, I
>>> noticed several pics such as 006 and 010 that show gross open
>>> breakout between the via PAD (foil copper) and via BARREL (plated-
>>> up copper). There is no evidence of selective or wave soldering on
>>> many of these. The breakout is on the TOP side with no evidence of
>>> additional solder applied, therefore my only conclusion is that the
>>> root cause was purely the plating issues from the fabricator.
>>> dean
>>>
>>> -----Original Message-----
>>> From: TechNet <[log in to unmask]> On Behalf Of Dennis Fritz
>>> Sent: Monday, May 6, 2019 2:38 PM
>>> To: [log in to unmask]
>>> Subject: Re: [TN] Bad Vias - Need help determining the root cause
>>>
>>> Do you have a copy of IPC 9121 - troubleshooting guide? That has a
>>> large number of pictures of failed via holes, causes, and remedies.
>>>
>>>> On Mon, May 6, 2019 at 3:12 PM Christopher Brand
>>>> <[log in to unmask]> wrote:
>>>>
>>>> Greetings,
>>>>
>>>> I'm having issues with open vias on a couple of runs of PCBAs and
>>>> was hoping to get some help on finding a root cause or at least
>>>> point me in the right direction. I know that there is lots of
>>>> knowledge and experience on this forum and I'm hoping someone will
>>>> say they've seen this before, as my knowledge is rather limited on
>>>> this.
>>>>
>>>> Here are a few photos of the vias in question.
>>>>
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__ludlums.com_software_BadVias_badvia-5F01.jpg&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=LmNZumVuc-aB-duabR-Sh7bWYujYHapt9x3t3Yvsa1s&m=lkESH8bB0gxL88Ex73cLR3Zi7VviUb-3kOB1lRh-x10&s=AiiO7LpdGl3gDNC9CwFstKGOQHIsqSyAt_TCLJpBUHk&e=
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__ludlums.com_software_BadVias_badvia-5F02.jpg&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=LmNZumVuc-aB-duabR-Sh7bWYujYHapt9x3t3Yvsa1s&m=lkESH8bB0gxL88Ex73cLR3Zi7VviUb-3kOB1lRh-x10&s=uRHRD__p4so4BdQN_1zgkgsmAx7vyM-0QkXdaKxmDpo&e=
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__ludlums.com_software_BadVias_badvia-5F03.jpg&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=LmNZumVuc-aB-duabR-Sh7bWYujYHapt9x3t3Yvsa1s&m=lkESH8bB0gxL88Ex73cLR3Zi7VviUb-3kOB1lRh-x10&s=pzZ1pOH_vEbbNFd2PT1a3xGsEP6X32wHpGT2IbjcgrA&e=
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__ludlums.com_software_BadVias_badvia-5F04.jpg&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=LmNZumVuc-aB-duabR-Sh7bWYujYHapt9x3t3Yvsa1s&m=lkESH8bB0gxL88Ex73cLR3Zi7VviUb-3kOB1lRh-x10&s=AnZm490vpAbwZQPZlnl3YimktIFHztuH59cP2wwtkI0&e=
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__ludlums.com_software_BadVias_badvia-5F05.jpg&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=LmNZumVuc-aB-duabR-Sh7bWYujYHapt9x3t3Yvsa1s&m=lkESH8bB0gxL88Ex73cLR3Zi7VviUb-3kOB1lRh-x10&s=JjRY1vV43Dic_yzKxxmN9o5GfdiH25QP8KCzsqu1dEc&e=
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__ludlums.com_software_BadVias_badvia-5F06.jpg&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=LmNZumVuc-aB-duabR-Sh7bWYujYHapt9x3t3Yvsa1s&m=lkESH8bB0gxL88Ex73cLR3Zi7VviUb-3kOB1lRh-x10&s=VQz9SEsXuslzSIKgPqumDrT_WFTCv5go7xdwQiM8i_s&e=
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__ludlums.com_software_BadVias_badvia-5F07.jpg&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=LmNZumVuc-aB-duabR-Sh7bWYujYHapt9x3t3Yvsa1s&m=lkESH8bB0gxL88Ex73cLR3Zi7VviUb-3kOB1lRh-x10&s=tO6cNmgg4ltqd5niaNrL3Scfx5Bl1lOF3r7l4-Hj0wo&e=
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__ludlums.com_software_BadVias_badvia-5F08.jpg&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=LmNZumVuc-aB-duabR-Sh7bWYujYHapt9x3t3Yvsa1s&m=lkESH8bB0gxL88Ex73cLR3Zi7VviUb-3kOB1lRh-x10&s=Vq-1_JDOWImYM2uFK2ulU79wW0vfyDD63DWl7kGDwqg&e=
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__ludlums.com_software_BadVias_badvia-5F09.jpg&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=LmNZumVuc-aB-duabR-Sh7bWYujYHapt9x3t3Yvsa1s&m=lkESH8bB0gxL88Ex73cLR3Zi7VviUb-3kOB1lRh-x10&s=Z9ss-Dea-EvmKRc-KYbqNcQu2uyI_S4faPfDB4DiD2g&e=
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__ludlums.com_software_BadVias_badvia-5F10.jpg&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=LmNZumVuc-aB-duabR-Sh7bWYujYHapt9x3t3Yvsa1s&m=lkESH8bB0gxL88Ex73cLR3Zi7VviUb-3kOB1lRh-x10&s=8ha5umWQAg9f8fzQbyKmsV3H-xJN0iPmzF_t8__29Pc&e=
>>>>
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__ludlums.com_so
>>>> ftware_BadVias_badvia-5F11.jpg&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=
>>>> LmNZumVuc-aB-duabR-Sh7bWYujYHapt9x3t3Yvsa1s&m=lkESH8bB0gxL88Ex73cLR
>>>> 3Zi7VviUb-3kOB1lRh-x10&s=gqzLwueqGGBRbtl6_HNVSti6fl3iw0W5WVM7XF_1BL
>>>> M&e=
>>>>
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__ludlums.com_so
>>>> ftware_BadVias_badvia-5F12.jpg&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=
>>>> LmNZumVuc-aB-duabR-Sh7bWYujYHapt9x3t3Yvsa1s&m=lkESH8bB0gxL88Ex73cLR
>>>> 3Zi7VviUb-3kOB1lRh-x10&s=n-d0XmSo6p_UmNE4CACDoiHNrjLJ8i0Vq22pvym8wQ
>>>> M&e=
>>>>
>>>> On some, the via barrel has a void in the center and on others the
>>>> edge of the barrel doesn't connect with the pad, Both issues are
>>>> causing an open via as you can see in the photos.
>>>>
>>>> I know that the board shop recently changed up their plating tanks
>>>> (new chemical and power supply). Could these bad vias be the
>>>> result of insufficient current in the plating process or some other
>>>> process?
>>>>
>>>> I'd be much appreciative of any insight this forum could give.
>>>>
>>>> --
>>>> Thank you kindly,
>>>>
>>>> Christopher Brand
>>>> Ludlum Measurements, Inc.
>>>> 501 Oak Street
>>>> Sweetwater, TX 79556 USA
>>>> (325) 235-5494 Phone, ext:3318
>>>>
>>>
>>> --
>>> Denny Fritz
>>> Consultant
>>> 812 584 2687
|
