Homebrew PCBs

Hi Adam

>Very rewarding work. Are the boards through hole plated or 
>just plated on the outside ? I only ask because I wasn't 
>sure if you have the electroless up and running.

Yes, they are through hole plated. :-)

> From what i've gathered, electroless copper processing is 
>by far the most troublesome. If you get that understood, 
>then everything else is a little easier. Since you are 
>paying good money for these chemicals, then you should 
>expect good support from the suppliers.

Mr. D. Bungard - is very helpfull. He is reachable on the phone and
also answers e-mails (usually within a day). He gave many good tips
and information.

>Will your process use panel plating method for producing 
>through hole PCBs ? If so what photoresist will you be using 
>to seal the holes from the copper etchant ? Normally they 
>are "tented" across with dry film negative resist.

I'm not sure about the names of the different methods, so let me
describe how it works:

As you can see I have 5 bath's. 

1 - A cleaning solution (7 minutes) followed by static and spray rinse
2 - so called "pre dip" (1 minute)  NO RINSE after this step
3 - activation (7 minutes, this is the most expensive one - it
contains paladium) followed by static and spray rinse
4 - intensifier (4 minutes). This bath should transport the paladium
that happen to stay on the copper sides into the holes also thereby
avoiding an other wise needed cleaning step of the pcb. Still, static
and spray rinse is requiered
5 - the electrolytic bath (24 minutes) followed by static and spray
rinse.

The static and spray rinse times is one minute each.

This will produce plates that have 35 u of copper if you start with
copper plates that have 18u alreay. After this a photoresist is
laminated on the board. The negative mask is made in a way so as the
holes are not there, that said, the hole areas do get light during the
exposion and hence they will not be etched. The developement of the
photoresist is made with soda. After the etching of the board the
remaining parts of the photoresist is once more "developped" with
natriumhydroxid solution.

I hope this explains yours and also Hans Wedemeyer's questions. If not
feel free to ask more.

Markus

>Adam
>
>Markus Zingg wrote:
>> Hi folks!
>> 
>> I'm a happy man! See the pictures of the first sucessfully through
>> hole plated PCB on the page!