The famous Silicon Valley RLM process was selective solder over
tin/nickel.  We perfected the tin/nickel at H-P's Porter Dr. PCB facility
in 1967 and used it as a final finish for many years.  It is almost
straight out of the "Metal Finishing Handbook" as the 'chloride/fluoride'
bath with pure tin anodes.  When I joined them in 1969, I started to use a
Gold Flash or a Bright Tin Flash over the tin/nickel because it was so
hard to solder to after the protective oxide had formed on its surface.
But it is a remarkable alloy with properties far better than nickel or
tin.  IF YOU COULD CONTROL THE STRESS!
Happy Holden
APM



Steve Hodge <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
08/17/2005 04:31 PM
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Subject
 HASL over nickel






I believe the process for the selective solder over nickel (RLM) used
tin/nickel and not pure sulfamate nickel. In the case I cited, we had to
put on the immersion gold to prevent passivation in between nickel and
HASL
processes.

At 02:12 PM 08/17/2005, you wrote:
>Which works for a plating process, not too sure if the same applies where
>the nickel is happily oxidizing all of the time it is out of a plating
tank.
>
>John
>
>------------------------------------
>Avanex
>John Burke
>Senior Manager RoHS Compliance
>[log in to unmask]
>40919 Encyclopedia Circle
>Fremont
>CA 94538
>tel: 510 897 4250
>fax: 510 979 0189
>mobile: 510 676 6312
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]]On Behalf Of Scott B. Westheimer
>Sent: Wednesday, August 17, 2005 1:01 PM
>To: [log in to unmask]
>Subject: Re: [TN] HASL over nickel
>
>
>The was actually a process back in the 70's called RLM. For you that
worked
>in Silicon Valley back then it stood for Robert L Mac the owner of Santa
>Clara Circuits who had the process patented. It was a nickel plated board
>that was then covered completed with screen ink, sorry no dry film back
>then, except for the pads and then tin leaded plated and reflowed. Was
there
>any issues? Not sure but there was a lot of boards made that way, for
>several years.
>
>Scott B. Westheimer
>Colonial Circuits




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