Subject:                         Time:   1:04 PM
                           FAB: Post plasma Cleaning        Date:   8/19/97

I need advice or suggestion on cleaning process after laser drill via.

We use YAG (UV range, 355 nm) to drill microvia in flex material
(Cu/polyimide/Cu).  The Cu thickness is 0.2 um+  and polyimide is 1-2 mil
thick.  Can anyone share your experience about cleaning (wet, dry,...etc.)
after laser drill and before metallization step (via fill)?  The criteria are
(a) maintain the adhesion between original Cu and polyimide without
delamination (b) good adhesion between etch via wall and metallization.

Thank in advance.

Bill Chou
Fujitsu Computer Packaging Technologies
(408) 943-7721
Fax: (408)943-7790
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