Yasmeen,

What you are seeing is most likely due to localized insufficient supply
of copper ions at the cathode due to no agitation. In other words, you
have become "mass transfer limited" in the regions where mixing (which
supplies 'fresh' copper ions to the surface) is poor. This causes the
"boundary layer" to become thicker, making the deposit powdery rather
than smooth.

There are several options to eliminate this. Obviously, improving
agitation would help. You might consider raising your copper
concentration. You might also wish to consider bath additives such a
brighteners or levelers. These can be evaluated quickly and effectively
using a Hull cell.

I hope this is of some help. Don't hesitate to contact me if I can
explain further.

Jonathan Meigs
AlliedSignal Oak-Mitsui

-----Original Message-----
From: nishath yasmeen [mailto:[log in to unmask]]
Sent: Tuesday, January 05, 1999 3:58 PM
To: [log in to unmask]
Subject: [TN] Porous copper deposits


Hello everyone! I have a question about the effect of agitation in acid
copper plating tanks. Why is the copper very porous and burnt when there
is no agitation in the tank? What actually causes the copper to be
porous?
Thanks in advance,
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
################################################################