Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Jan and the group,

I'll be glad to do a write up on making plated through holes. How
much detail does everyone want? There are about 60 steps to the
whole process if you break it down.

I could give an overview of the entire process and then in future
posts give more details on each step. The hard part of the process is
knowing what to do when something goes wrong. So another part could
be a discussion on problem solving.

BTW, the activated solution mentioned is actually a super activated
palladium chloride catalyst. My shop was the first one in North
America to install this process in 1990. It was invented by Eric
Harnden who owns a company called Solution Technology in California.
I worked with Eric in the early days right after he received his
patent for this process. We ran his solutions along side our
electroless copper tanks and found them to be superior. At that point
we junked the electroless system and converted everything to the new
process by early 1991.

At first there was much resistance to using this new method because
the MIL SPEC at the time only allowed electroless copper. This kept
the new process out of the big shops but one by one they caught on
and now Eric has licensed the technology to all the big chemical
suppliers. The magic ingredient was lignin vanillin extract!! The
catalyst tank smelled like a milk shake! I'm sure that Eric Harnden
has made a fortune from his invention.

The idea behind this catalyst was to get such a low resistance
between the two board layers that the electrolytic copper would plate
right over the catalyst layer. This eliminated the electroless copper
part of the process and about thirty minutes of time per load.

I'll write up the basics stating at the beginning and post them over
the next few days.

Tom