Hello Pradeep, 
 
I trust you are not stressing entire panels but just coupons from each. You 
 also do not cite the conditions. Abusive/excessive testing can make a  
good product marginal or even take it over the edge to unreliable. 
 
As for processing, "the devil is in the details" as the old saying  goes so 
it is hard to comment with any real authority. That said, control of the  
drilling equipment, drill parameters and tools is vital, moreover, the same  
chemistry can deliver very different results depending on times, 
temperatures  and solution maintenance. In addition rinse water and rinsing are very  
important and often overlooked. In short, control your process and you 
control  your product. 
 
Best wishes, 
Joe
     

 
 
In a message dated 6/2/2009 10:58:12 P.M. Pacific Daylight Time,  
[log in to unmask] writes:

Dear  all,

Our routine tests for one of our customers include 6X thermal  stress on 
every panel before despatch. Currently we are evaluating a new  elctroless 
chemistry. We would like to have some suggestions from the  technetters on 
which of the electroless chemistries are best suited for  meeting the 6X thermal 
stress tests - Low build / medium build / high build.  We do a copper 
strike after electroless plating and before pattern printing.  We also do a 
plasma desmear followed by a chemical desmear which will achieve  an etchback of 
5-8 microns. Kindly share any suggestions which you feel will  further 
improve the PTH relaibility. We use 175 Tg laminate and prepreg of  Nelco 
(N4000-6) and achieve a pretty good hole wall during drilling.  

In the past we have had a few instances of innerlayer separation  during 3x 
and 6x thermal cycles. Almost all the panels pass 1x thermal  stress.

looking forward for the valuable  inputs

Rgds

Pradeep  Menon


-------------------------------
Micropack Ltd, Bangalore,  India

---------------------------------------------------
Technet  Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------


**************Shop Inspiron, Studio and XPS Laptops at Dell.com 
(http://pr.atwola.com/promoclk/100126575x1222616459x1201464730/aol?redir=http:%2F%2Fad.d
oubleclick.net%2Fclk%3B215218145%3B37264238%3Bd)

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------