Dear Madam,

Thank you for your reply,

We are in production with the Positive ED Resist named PEPR 2400
from Shipley. We are doing 100% of innerlayers and ramping up on
the outerlayers. By the end of the month, we should be producing
about 800 panels a day with the ED Resist.

Light into the holes is needed only for non-plated holes.. If the
design of the board is 3 mils, then we cannot use diffusion paper
as it will affect too much the track definition, but let's say
we have some more common boards where track width is not an issue,
then we will eventually use diffusion paper in order not to need
to do a second drilling for non-plated holes.

If the ED subject interest you, i can e-mail you more datas.

We choosed Positive resist for several reason :
Among them, the fact that in either inner and outer layers we
use the same parameters and process, where at exposure of the
resist, the eventual dust will become a copper short instead
of interruption has been seen as a reducer of rejects.
(positive film, where non-exposed resist will remain as etch resist)

Other advantage is that we do not need hole pads, thus saving space
for denser designs.

Resolution is not a limitation, 1, 2, 3, 4, mils can be mass-produced
with the exception due to the copper thickness, The less copper to be 
etched, the finer we can go. Unfortunately, for outer layers we are
limiting ourselves with the additionnal plated copper.

For your information (i hope that i am not divulging secrets..)
OMNI Circuits is at approximately the same level of production
with their PEPR ED Resist line.

In Switzerland, there is a second PCB manufacturer that is using
Positive ED Resist, but choosed the Optimer from Ciba.

I wonder if Japanese reading this message, are willing to share their
much more extensive experience with us...

Respectfully your
Roland


Roland Jaquet         Technical Director
Henri Jaquet SA       PCB manufacturer
Geneva Switzerland    Prototypes and small qties
tel. xx41-22-794-7878 fx. xx41-22-794-3052
[log in to unmask]