I remember that tool. Originally it was produced by Tegal corporation back in
the late 70's early 80's. Someone else produced it later on and it worked
quite well for removing the hydrogen bubbles that were a by-product of
phosphoric acid + aluminum. The problem with it was it required a vacuum pump
and you can imagine the results after a while inside of the pump. There are 2
other ways to reduce the problem. The first one was called a cascade etcher.
The wafers sat on an incline and the solution ran over the surface of the
wafer. The aggitation from the stream of acid did a very good job reducing
bubbles on the surface. The other method which I think works the best of all
is a single wafer spray system. The atomized acid has enough impingement on
the surface to break up and remove bubbles and the uniformity across the
wafer is around 1-2% 1 sigma.

If you are interested in any of these approaches we will gladly build one for
you that can accommodate 4-8 " wafers with no hardware changes. You can
contact me directly
Bob Henderson
Process Integration,LLC
480-558-1156