Paul,
 
There are a few suppliers that manufacture OSP.  The most common are from Enthone (Entek CU-56 and Entek CU-106A.)  I am not sure of the composition but it is a clear solution that is applied to the PCB  at the end of the process.  It is capable of preserving the copper from oxidizing.  However, the shelf life for the boards is an issue.  There has been alot of controversey about that.  I have heard anywhere from 3 to 6 months if the boards remain shrink wrapped.

One nice feature of OSP is that you can have the surface flatness of the copper as opposed to using hot air leveling that does not guarantee a good surface mount flatness.  

On the other hand, a major draw back appears if the finished boards are handeled by bare hand.  The oil in the skin destroys the OSP coating defeating the whole purpose.

I suggest you contact enthone for more specific information on their products.

Hammad



---------- Forwarded Message ----------

FROM:    Paul Tomlinson <[log in to unmask]>
TO:      [log in to unmask]
DATE:    Thu, 3 Jun 1999 07:57:34 -0400

RE:      [TN] Organic Soldereability Preservative.

Hi Technetters,

Has anybody any information on OSP (Organic Soldereability Preservative) re
its effectiveness as against solder coating, for enhanced solderability.

I have never heard the term OSP.

Paul

END --------------------- [log in to unmask] END


           While there never is a perfectly right answer,
           there are always several perfectly wrong ones!

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