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Subject:
From:
"Stadem, Richard D." <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Stadem, Richard D.
Date:
Wed, 28 May 2014 17:41:31 +0000
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Well, your "bantering" sure does help the rest of us! Thanks to Joe, Brian, and Graham!

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Joe Russeau
Sent: Wednesday, May 28, 2014 12:32 PM
To: [log in to unmask]
Subject: Re: [TN] PCB Cleanliness Via Ion Chromatography Poll (informal)

Graham,

I do not disagree with your first point.  However, I do concur with Brian that SIR and ECM tests are useless for bare board cleanliness checks due to the long duration of time required.  They simply are too long to keep up with production requirements.

As to your second point... I have never, nor would I ever profess or imply that IC can tell you that your end product is going to be reliable.  It gives you information about one aspect of reliability and only one.  There are far too many aspects that can affect reliability.  That said, I don't know that it would be correct to say that any one test by itself can predict reliability.  The point of testing is for risk mitigation (borrowed risk mitigation from Mark Northrup).  To that end, the engineer has to do his or her due diligence in selecting the testing that will give them peace of mind.  It might be IC, it might be SIR, it might be FTIR, it might be in-circuit testing, it might be cross-sectioning, it might be all of these combined.  At the end of the day, reliability is a multi-faceted puzzle and I would never hang my hat on any one test to determine that for me, especially if I have never done any testing prior.  Sorry this is way off topic.  I blame Graham.  ;-)

In terms of ROSE, as you point out it is grossly misused today and IMHO it really needs to follow the path of the Dodo. I know that last part may stir controversy, but it is my opinion.  However, as I have stated in IPC meetings, we keep on trying to polish this test and its relevance is not what it once was.  Some make the case that it is still applicable as a process control tool. Perhaps for bare board cleanliness checks it still could be of use, provided it has been correlated to something more accurate, like IC testing.  However, many blindly apply the value from J-STD-001 to bare boards with little understanding or acknowledgement of how the value was derived or what it was intended to measure.  The big complicating factor in my mind is that the extraction solvent used by ROSE and even for IC testing has limited use or many of the newer "no clean" fluxes.  However, I will digress now as to go any farther is to go way off-topic and I don't know that our banter is helping Rich.

Peace,

Joe Russeau


----- Original Message -----
From: "Graham Naisbitt" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, May 28, 2014 12:25 PM
Subject: Re: [TN] PCB Cleanliness Via Ion Chromatography Poll (informal)


Joe, Joe, Joe,

Please excuse me but:

SIR / CAF tests will tell you whether your end product might be reliable 
from an electro-chemical standpoint. They will not tell you what is present 
causing any problems. They do not discriminate ionic and non-ionic 
contamination.

IF you encounter a problem, then IC will tell you what is there causing the 
problem, but it cannot tell you if the end product will be reliable - 
keeping in mind that there exists non-ionic contaminants.

So, qualify the process using SIR / CAF as appropriate, then use Process 
Ionic Contamination Testing = PICT, to control the process. As Brian rightly 
points out, ROSE is a grossly misemployed test. I would love to rewrite it 
but, as many friends in the industry have pointed out, including you Joe, I 
will most likely die in the attempt hence I am using the term PICT and 
starting from that basis. It will appear as an IEC test soon.

Kindest regards

Graham Naisbitt

On 28 May 2014, at 14:36, Joe Russeau <[log in to unmask]> 
wrote:

> Hello Brian,
>
> See my responses to your comments below, designated by ***.
>
> Best Regards,
>
> Joe Russeau
>
> ----- Original Message ----- From: "Brian Ellis" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, May 28, 2014 3:12 AM
> Subject: Re: [TN] PCB Cleanliness Via Ion Chromatography Poll (informal)
>
>
>> Let me add a couple of eurocents worth.
>>
>> 1. Ion chromatography is useless for incoming board testing. Far too long 
>> and far too expensive. By the time you have the results from a valid 
>> sample of a batch (say 1-5%), your board will be obsolete.
>
> *** Again, I have to disagree that the "tool" is useless for incoming 
> board testing.  It has two very important analytical features that make it 
> applicable.  Those two features are selectivity and sensitivity.  Now I am 
> not saying it is a perfect tool. Like any analytical technique it has its 
> limitations.  However, it is has a tremendous amount of capability if it 
> is properly set-up and the user understands how to apply it AND 
> understands the material sets he/she is evaluating.
>
> Does it take too long?  Possibly, it depends (Doug just add that to my Mt. 
> Dew tab).  It depends on what too long means.  If your goal is to have an 
> immediate answer then yes it takes too long.  I know many that utilize 
> ROSE to test/control/track incoming board cleanliness because it is quick 
> and gives an immediate answer, but when you ask them how they know the 
> board is clean, I often hear silence on the other end of the phone.  On 
> the other hand, if your goal is to understand what is present on the 
> surface of your board and what impacts certain ions may have on product 
> reliability, then perhaps the time to test isn't so long.  It really boils 
> down to your goal for testing.  Also, if all your looking for are simple 
> anions and cations, then IC systems can churn those results out in about 
> ten minutes (depending on your set-up).  If organics are in the sample 
> matrix, then more time is going to be needed to evaluate them.  IC is not 
> an immediate answer I'll grant you that, but it gives those that are 
> trying to understand their residue picture more information about it.
>
> As for expense, it can be expensive depending on who is doing the testing 
> and what is being analyzed.  But keep in mind that part of the expense is 
> paying for the expertise and knowledge.  I know that it is difficult to 
> place a price on that, but hey if it helps someone avoid a process line 
> from being shut down, then the expense of testing is a pittance by 
> comparison.
>
>
>>
>> 2. SIR or ECM testing is useless for incoming board testing. Far too long 
>> and far too expensive. By the time you have the results from a valid 
>> sample of a batch (say 1-5%), your board will be obsolete.
>
> *** Totally agree.
>
>>
>> 3. IC, SIR and ECM are qualification tests, unsuitable for incoming goods 
>> testing. Because of the chemical nature of the surface finishes, it is 
>> impossible to extrapolate the results obtained during qualification to 
>> production conditions, because there may be slight differences in the 
>> stoichiometry of the resins and their various treatments in board 
>> manufacture (or even changes of laminate manufacturer) etc.
>>
>
> *** My only disagreement with your statement above is classifying IC as a 
> qualification tool.  I would not classify it as such. Why? Because there 
> is a lot of subjectivity between the experts in defining what is 
> considered clean and not clean.  IPC-5704 helps some with incoming board 
> cleanliness by setting up an industry standard that has been mutually 
> agreed upon within committee.  However, no such standard exists for 
> assembly cleanliness and some might be misled into thinking that IC can be 
> used to qualify their products.  I'd say it can help in understanding the 
> residue picture, but I wouldn't rely solely on those results to say all is 
> good.  It provides data into one aspect of reliability.  Other testing may 
> be required depending upon what you are qualifying.
>
>> 4. In my considered opinion, the *ONLY* practical test for incoming 
>> boards in a production environment is ICT (Ionic Contamination Testing), 
>> sometimes incorrectly called the "ROSE" test for historical reasons. It 
>> is fast, if rough and ready, and will detect the presence of most (but 
>> not all) of the harmful contaminants and bad stoichiometry of resins, 
>> without necessarily identifying them (some testers will give indications 
>> of the causes of problems by software analysis). Don't underestimate this 
>> valuable tool.
>
> *** No comment.
>>
>> Brian
>>
>>
>> On 23.05.2014 16:27, Richard Kraszewski wrote:
>>> I actually sent this out on May  16th, but never got a single response. 
>>> Hoping that was not due to lack of interest, but rather due to the 
>>> TechNet being down. Hence, I think I'll try this one more time.
>>>
>>> I am  hoping to run an informal " min straw poll " here.
>>>
>>> Questions stated  are as follows:
>>>
>>>
>>> 1.       "Is your organization testing  incoming  PCB cleanliness  via 
>>> ion- chromatography?             Replies such as "YES" or "NO" will 
>>> suffice, but more detailed explanations are also acceptable.
>>>
>>>
>>>
>>> 2.       " If testing via IC, do you use IPC -5704 Table 4.1 limits or 
>>> other?                                                Replies such as " 
>>> IPC"  or "other"  will suffice, but more detailed explanations are also 
>>> acceptable.
>>>
>>> What's in  it for  you?   I will summarize and post the results after a 
>>> few days of replies.
>>>
>>> Rich  Kraszewski
>>> Senior Process Engineer
>>> Plexus
>>>
>>>
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