Many Thanks Dave,

are the BTC Task Group  (5-21h ? ) doing same void limits assessment for the coming  IPC-7093 A Review ?

Best Regards
Gabriele

-----Messaggio originale-----
Da: TechNet [mailto:[log in to unmask]] Per conto di David Hillman
Inviato: domenica 4 marzo 2018 01:54
A: [log in to unmask]
Oggetto: Re: [TN] Bottom Termination Components (BTC) Voiding Limits

Hi Wayne - you have good timing with your question as I can give you the latest info from the IPC committee meeting last week. The JSTD-001 committee had a comment submitted asking for void criteria for BTCs.  A small task group with global representation from several industry product segments was formed to review the issue. We reviewed the issue with data resources from consortia, IPC and SMTA resources.  We had one very specific
conclusion: Any void criteria that would be put into the JSTD-001 specification would be addressing solder joint integrity only. Many BTCs have either thermal or electrical functional needs which is a design issue that should be addressed during the product design phase.  Here is what the task team responded back to the JSTD-001 committee with:

"The JSTD-001 QFN Void Criteria task group recommends that a "request for data" be issued as a review of the current available industry data was found to not be sufficient to establish a data based maximum void criteria for solder joint integrity. The voiding criteria requirements pertaining to the functionality of a QFN or other Bottom Terminated Components (i.e.
thermal or electrical performance) are a design function and not part of the IPC-JSTD-001 specification scope. The "request for data" responses should be sent to the QFN Void Criteria task group by October 31st, 2018 so that they can be reviewed prior to the 2019 IPC JSTD 001 APEX committee meeting. The  JSTD-001 QFN Void Criteria task group will provide a void criteria recommendation to the IPC JSTD 001 committee based on the data submissions at the  2019 IPC JSTD 001 committee meeting."

The void number you listed - especially the 25% - have little to no technical data justification in terms of solder joint integrity.The
JSTD-001 BTC Void task group is looking for DOE/test/investigation data and there will be a recommendation to the JSTD-001 committee for review at the
2019 committee APEX meeting. I understand that seems like a long time but any criterial that is put into the JSTD-001 specification must be done based on data as those requirements results in costs to the industry.

A number of OEMs verbally committed to providing BTC void data to the
JSTD-001 BTC Void task group so I am confident the issue will be resolved within the year. If anyone has  data they would like  to submit to the task group, please send it to me and I'll make sure it is included in the data review.

Let me know if you have any additional questions.


Dave Hillman
IPC JSTD-001 BTC task group lead
Rockwell Collins
[log in to unmask]


On Sat, Mar 3, 2018 at 6:18 PM, Wayne Showers <[log in to unmask]>
wrote:

> I do not know of an IPC criteria on this.  I have seen 25% (The BGA
> criteria) cited, but this is not, to my knowledge accurate.
> The limits I have used in the past are 50% Coverage with no void 
> exceeding 15% in the center and no more than 10% anywhere else.
> I also used a 70% Coverage and 10% Void criteria for a very heat 
> sensitive application.
>
> Question 1: Is there now a citable IPC criteria? and if NO, Question 
> 2: What are some of this groups recommended criteria?
>
> Thanks and Regards, Wayne Showers, NPI/Technical Manager, 4Front 
> Solutions
>


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