John;

We have used double treat materials for quite a few years. I offer the
following comments:

At 09:51 AM 6/18/96 CDT, John Gully wrote:
>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)

We have found it quite forgiving. It is not as sensitive to normal handling
defects, as associated with oxides. Even fingerprints do not cause
delamination, during temperature cycling.

>4.  There are difficulties in AOI-ing the layers     

Enough cannot be said about the difficulty at AOI. Don't let this matter go
lightly. It is very unpredictable, and certainly not consistent. You will
have to adjust the AOI for EACH PANEL tested, not each lot! Some double
treat just won't allow imaging to take place. This holds true for reflective
AOI systems. If you use laser flourescent AOI, double treat becomes a
non-issue, since the AOI is not looking at the copper. There is also an IR
type AOI that does well with double treat copper.

>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.

To maintain good copper etching, you should first strip the double treat
from the areas to be etched. Most etchants do not do well with zinc. If you
do not, etching quality becomes unacceptable. You will probably need a
machine for stripping. When we purchased a new etcher, we refurbished and
used the old etcher for this purpose.

>7.  Is oxide necessary when processing double treated polyimide 
>    layers.  RBO (Atotech) is a recommended oxide for polyimide 
>    layers and improves prepreg adhesion?

We do not have to process the double treat any further when using polyimide
materials. As a matter of fact, we do not even have oxide capability.

>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
>  
>
>
Regards,

Gary Ferrari
Tech Circuits
(203)269-3311
[log in to unmask]