The electron source is the cathode (negative polarity,
excess electrons) and the receiving end is the anode ( positive
polarity, missing electrons).
Ramon
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of R Sedlak
Sent: Wednesday, May 24, 2006 6:26 PM
To: [log in to unmask]
Subject: Re: [TN] electroless gold thickness'
Cheryl:
Plating from solutions involves transfering electrons to ions floating
in solution, converting them to metals, hopefully on the surface we
want.
There are three kinds of plating from solutions...
immersion plating
electroless plating
electrolytic plating
The three different methods differ in the source of the electrons...
In immersion plating, some of the substrate dissolves, releasing
electrons, which cause the metal in solution to plate out. This kind
of plating is self-limiting, when the substrate material gets covered,
plating stops. This is why you cannot get gold over about 0.25 micron
in IMMERSION gold.
In electroless plating, another chemical in solution donates electrons
to the metal ions in solution, causing them to plate out. There is
theoretically no limit to the thickness you can achieve using
electroless plating... thus achieving 0.5 micron gold can be done with
ELECTROLESS gold.
And for the record, the rectifier, also known as the "electron pump",
pumps electrons from the anode to the cathode in electrolytic plating.
Rudy Sedlak
RD Chemical Company
Cheryl Johnson <[log in to unmask]> wrote: I believe I have
seen this somewhere, and have tried searching the archives, but am
having trouble finding it.
Does anyone know of any processes for electroless gold that can obtain >
.5 micron thickness (without needing bus bars?) Or any way to get > .5
micron gold on a flex without bus bars?
Thank you!
Sincerely,
-----------------------------------
Cheryl Johnson, C.I.D.+
Manager
ExcelStor US Office, Engineering Services
Email: [log in to unmask]
Tel: (303) 684-7291
Fax: (303) 684-7268
Mobile: (303) 809-5815
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