Is it electrolytic, or electroless?
During the plating process some gas (hydrogen I believe) may be produced at
the surface of the work being plated. This gas forms bubbles that may become
attached to the work itself, these bubbles prevent plating in those areas
resulting in pits, voids, absence of plating, etc.
Ensuring your chemistry is within prescribed variables, acid level, copper
level, pH, Buame', contaiminates, etc, can all affect this condition. Also,
cleanliness of product before plating, contaminates attached to the work
before being plated can themselves trap and contain these bubbles causing
similar conditions.
Ensure current (volts/amps) are correct for the surface area being plated,
too high of current can generate too much hydrogen at the surface of the
work...
Hope these generate some ideas, also, there are much more qualified persons
here in TechNetVille that may be able to provide more precise direction,
good luck
Franklin
----- Original Message -----
From: "Nishath Yasmeen" <[log in to unmask]>
To: "'Franklin'" <[log in to unmask]>
Sent: Wednesday, June 09, 2004 3:37 PM
Subject: RE: [TN] Need help with Bubbles in plating tanks
> Thanks Franklin for your input. Regarding reason 1. I'm using acid
> copper and I don't usually see any bubble formation at the anode... I
> think it is #2. The issue I have is our equipment guys have a tough time
> finding the leaks and so are pushing for obtaining bubble eliminating
> devices.
> Why does #1 happen & can this be harmful?
>
> Regards,
> Yasmeen
>
> -----Original Message-----
> From: Franklin [mailto:[log in to unmask]]
> Sent: Wednesday, June 09, 2004 1:19 PM
> To: [log in to unmask]
> Subject: Re: [TN] Need help with Bubbles in plating tanks
>
> Well it seems you've already detected the bubble, yes? So the issue is,
> whats causing them, if you are observing bubbles in solution it may be
> caused by 2 things that I am aware of, 1) a chemical reaction causing
> gas to
> form in solution, and 2) cavitation in pumps (recirculation, filtration,
> etc).
>
> In my experiencing, the 2 item is the most common...check to ensure air
> is
> not being introduced into the pump system...good luck
>
> Franklin
>
>
> ----- Original Message -----
> From: "Nishath Yasmeen" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, June 09, 2004 1:04 PM
> Subject: [TN] Need help with Bubbles in plating tanks
>
>
> > We are plating copper onto wafers with the plated area dimensions
> being
> > in Micron (E-6 meters) level. We are seeing bubbles in plating tanks
> > that are causing unplated areas or depressions in plated areas.
> >
> > Our EE group has tried and has given up on the tanks and how far they
> > can go fixing the tanks.
> >
> >
> >
> > Does anyone out there know any degassing equipment or bubble sensors
> or
> > something that can detect and eliminate bubbles.
> >
> >
> >
> > Thanks & Regards,
> >
> > Yasmeen
> >
> >
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