John,
     
     1. Watch out for epoxy spots on the copper (as recieved from the 
     supplier). You will see a lot of unetched copper at AOI due to this 
     problem.
     
     2. No you do not need special equipment. You will have to run some of 
     it differently however.
     
     3. If you are not careful with your resist process you will get 
     lock-in and never get the resist off. Don't laminate it too hot or 
     hold it very long. If the panels sit for 3 days or more with resist 
     applied you can start looking for the nearest dumpster.  Wet or dry 
     lam will work with double treat.  Don't let them tell you that you 
     have to do it dry.
     
     4. Unless you have older AOI equipment you will not have a problem at 
     AOI.
     
     5. Most people specify double treat copper when working with polyimide 
     to get improved adhesion. I don't know why anyone would tell you that 
     you should use oxide on polyimide. Normal lamination and post-bake 
     temps are sufficient to degrade oxide treatments. Double treat besides 
     having more surface topography does not degrade with temp.
     
     6. Your handling throughout the process will now become critical.  The 
     double treat is easily scuffed (shinners).  Any scuff shows up on the 
     outside of the finished board as an aesthetic defect.  You won't have 
     a functional issue but the board will look bad.
     
     Good Luck, the financial analysis says you're doing the right thing.


______________________________ Reply Separator _________________________________
Subject: FAB: Double Treated Copper
Author:  [log in to unmask] at corp
Date:    6/18/96 9:17 AM


Address,
     
We have a rep from EIS that is trying to sell us some Double 
Treated Copper (aka Trick-o-Treat Copper).  As with anything there 
are pro's and con's to materials.  I am slightly familiar with 
some of these pro's and con's of double treated copper, based on 
past readings.  What I do know about it:
     
1.  It eliminates Black oxide and Chemical/Mechnical Scrubbing 
    process
2.  Resist adhesion is improved due to the copper topography
3.  Handling parameters are increased prior to resist lamination
    (since there is no cleaning process prior)
4.  There are difficulties in AOI-ing the layers     
5.  Prepreg adhesion is improved at the lamination stage
6.  Is it true that new equipment is needed to process this 
    material?  EIS says no, but others I spoken with say yes.
7.  Is oxide necessary when processing double treated polyimide 
    layers.  RBO (Atotech) is a recommended oxide for polyimide 
    layers and improves prepreg adhesion?
8.  etc.,
     
Please add any additional information you may have that can help 
in our evaluation.  We have some double treated samples that we 
will be testing soon.  Thank you in advance.
     
John Gulley - PE
Dallas, TX