12 µ" = 0.3 µm. I'd say that you need at least 1 µm of electrolytic Au 
to avoid your problem. Chapter 23 of Reid & Goldie, Gold Plating 
Technology, provides 11 pages of dense material on Porosity. Current 
density is an important factor and Leeds and Clarke determined there is 
an optimum, as well as the composition. I seriously suggest this book 
(http://www.elchempub.com/epfiles/ep11.htm)

Brian

Lin Leo wrote:
> We have a product with mixed surface finishes-Electrolytic Ni/Au(
> Hi,
>  
> We have a product with mixed surface finishes-Electrolytic Ni/Au(Au thickness: ca. 12~20 micro-incheses; Hard gold Au-Co alloy) + ENIG(Electroless Nickel/Immersion Gold).  Because of customer's request, electrolytic Ni/Au has to be completed before patteren formation. Following electrolytic Ni/Au process, the manufacturing process for this board would pass through H2O2/H2SO4, SES(dry film striper-Copper-ammonia solution-Tin striper) and SPS(Na2S2O8) etching solution.  At final visual inspection, several Au surface defects were found.  Failure mode analysis shows a 2~10 micro-meters diameter round hole by SEM.  Cross-section shows that Ni was corroded and Cu was etched in severe defect.  We think these defects were qwing to Au porosity issue.  We carried out active carbon filtration for Ni & Au bath.  But the electrolytic Ni/Au quality could not keep in a stable level.  The defect rate was from 6~20%.  Does anyone have any experience or idea on this case?
> 
> Thanks
>  
> Leo
> 
> ___________________________________________________ 
>  ±zªº¥Í¬¡§Y®É³q ¡Ð ·¾³q¡B®T¼Ö¡B¥Í¬¡¡B¤u§@¤@¦¸·d©w¡I 
>  http://messeng
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 1.8e
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
> To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
> Search the archives of previous posts at: http://listserv.ipc.org/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
> -----------------------------------------------------
> er.yahoo.com.tw/
> 

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/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
-----------------------------------------------------