Yasmeen,
One cause of nodules is particles in the bath. The souce of particles can be
from the board, anodes and facilities.  Cleaning the boards, not allowing
the anodes to produce particles and  good filtration may be keys to
eliminating the problem.  High current densities at te edges will confound
the problem so techniques for making a more uniform field may need to be
implemented, dielectric shields and adjustment of anode exposure,...
Hope this helps
Richard Haynes
609-497-4584
-----Original Message-----
From: nishath yasmeen <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Monday, December 21, 1998 5:42 PM
Subject: [TN] Nodules in copper plating process


>Hello,  We are seeing huge nodules which occur mostly on the edges of
>the pattern for our acid copper plating process. The copper in the
>resist opening is of the normal height but near the edges it seem to be
>about 30ums thicker. Another notable thing is that this happens when the
>bath if very fresh i.e just after the anodes are filmed. Is this because
>of  a very high field in that region causing the copper to plate very
>high. Any suggestions will be appreciated.
>
>Yasmeen
>
>################################################################
>TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
>################################################################
>To subscribe/unsubscribe, send a message to [log in to unmask] with following
text in the body:
>To subscribe:   SUBSCRIBE TechNet <your full name>
>To unsubscribe:   SIGNOFF TechNet
>################################################################
>Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section
for additional information.
>For technical support contact Hugo Scaramuzza at [log in to unmask] or
847-509-9700 ext.312
>################################################################
>
>

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################