At 13:46 25/02/98 PST, you wrote:
>     Hi all,
>
>        We had run the OSP finishing for more than one year now. One
>     frustating problem that I can never get rid of is the stain on the OSP
>     surface.
>
>        It looks like some kind of water stain. It occurrence is
>     independent of acid clean, microetch, OSP bath temperature, process
>     speed, final DI rinse pressure, etc. In fact, I cannot find any
>     process parameter that can change the appearance of this stain.
>
>        We are using Enthone Entek OSP. The thickness, as determined by
>     spectrometer, is 30+/-10 micron. Solderability test is perfect. No
>     complaints from any customer concerning the quality of the OSP
>     coating. But this stain is very irritating.
>
>        Can somebody tell me how to eliminate the stain?
>
>     Regards,
>
>     Yee T.G.
>     Process Engineer
>     Hadco Corp.

Hi Mr Yee T.G.!
First of all - wellcome to the club of Frustrated OSP Process Engineers !
From Your message I just can guess , that You are working with horizontal
process . I don`t know the nature of the stains : on small pads , big areas
, bright , dull etc .
From our own experience , most of stain problems are related to :
1 ) drying stage
2 ) aged Entek
3 ) unproper transfer between Entek stage and the rinse
4 ) machinery problems

Try to find out , at which stage of the process the stains are visible the
first time .
Good luck !

Edward Szpruch
Eltek Ltd - Israel
Tel  972 3 9395050
Fax 972 3 9309581
E-mail :  [log in to unmask]

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
################################################################