Jack, Mitch,
I'm surprised that no one answered this myself. Anyway, The wrap plating
requirement forces the fabricator to plate extra copper so that after
planarization, the final copper thickness does not fall below the
minimum wrap requirement. They accomplish this a number of ways. They
can panel plate first, button plate, pattern plate into over sized
drilled holes, etc. Each fabricator will choose the methodology that
best fits his/her operation. To this end, if they must etch through
thicker copper, then they need to add more compensation to the artwork.
When the images are too close, then the extra compensation leaves the
space between the images too small for them to process reliably.
Therefore, your fabricator wants the hole spacing opened up to
accommodate his additional compensation requirements.
Regards,
Gary
Jack Olson wrote:
> wow, NO responses yet?
>
> I've read that paragraph three times now,
> and I'm still not sure what the problem is.
>
> It sounds like they are trying to maintain your 1mil annular ring
> requirement,
> and are working on a design with 4mil minimum clearances, but is it the
> fact
>
> that you need plugged blind vias what is causing the difficulty?
> Sorry I can't help, but I'm curious.
>
> I don't suppose IPC has a "HOTLINE" you can call to clarify requirements?
> HA.
>
> good luck,
> Jack
>
>
> On 4/10/07, Mitch S. Morey <[log in to unmask]> wrote:
>>
>> Hi all,
>>
>> I recently had this response from my fabrication house, and was wondering
>> if anyone else has run into this issue. I'm still trying to figure out
>> exactly what it means (e.g. costs me).
>>
>> ----------------------------
>> Due to blind vias/epoxy fill requirement & spacing on the outer layers, a
>> new copper wrap plating process cannot be achieved per IPC 6012B due to
>> spacing issues. I would like to verify if we can wave this process since
>> you have less than 4 mils space on your data. Please see below.
>>
>> In mid January of 2007, IPC released Amendment 1 of 6012B, updating it's
>> copper wrap plating spec (3.6.2.11.1) that reads as follows:
>>
>> Copper wrap plating minimum as specified in Table 3-2 shall be continuous
>> from the filled plated hole onto the external surface of any plated
>> structure and extend by a minimum of 25 um (984uin) where an annular ring
>> is required. Reduction of wrap-plating by processing (sanding, etching,
>> planerization, etc.) resulting in insufficient wrap plating is not
>> allowed.
>> XXX1 is committed to manufacturing your PCB's to the highest standards.
>> Due to the panelizing process, designs requiring a space of 4 mils or
>> smaller can not be built to this spec.
>> ----------------------------
>>
>> Thanks in advance.
>> Mitch
>>
>>
>>
>>
>
> ---------------------------------------------------------------------------------
>
> DesignerCouncil Mail List provided as a free service by IPC using
> LISTSERV 1.8d
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF DesignerCouncil.
> To temporarily stop/(restart) delivery of DesignerCouncil send: SET
> DesignerCouncil NOMAIL/(MAIL)
> Search previous postings at: www.ipc.org > On-Line Resources & Databases
> > E-mail Archives
> Please visit IPC web site
> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100
> ext.2815
> ---------------------------------------------------------------------------------
>
>
>
---------------------------------------------------------------------------------
DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF DesignerCouncil.
To temporarily stop/(restart) delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL/(MAIL)
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
---------------------------------------------------------------------------------
|
