The thickness of nickel may vary with the application but 200 microinches of
nickel is certainly on the high side. There should be no problem with 100
microinches of nickel for most applications. As for the original problem
described here,
the problem appears to be "water stains", simpy a problem of drying efficiency
(nicely described in another posting in this thread)....
Regards
Jacques Coderre
New Business Opportunities/Nouvelles Opportunités d'Affaires
e-mail:[log in to unmask]
Tel:(514) 534-6591
Fax:(514) 534-6800
[log in to unmask] on 07/08/98 09:51:56 AM
Please respond to [log in to unmask]
To: [log in to unmask]
cc:
Subject: Re: [TN] Re[2]: [TN] Au/Ni/Cu PROBLEM
Hi Matt,
Im sorry, but I have to agree with Rudy, we have always and forever
used 200 microinches of nickel as a barrier, and in most cases we have not had
a problem, except with some gold porosity in the early '80's.
Respectfully,
Les Connally
> From: [log in to unmask], on 7/7/98 4:51 PM:
> Rudy -
> I'm surprised to hear that you think 4 microns of nickel is thin.
> This is 0.16 mils, & many people specify down to 0.10 mils. You're
> suggesting putting on almost ˝ mil of nickel (2-3X of 4 microns)?
>
>
> Matt Byrne
> Hadco-Owego
>
> ______________________________ Reply Separator
> _________________________________
> Subject: Re: [TN] Au/Ni/Cu PROBLEM
> Author: "TechNet E-Mail Forum." <[log in to unmask]> [log in to unmask] at
> INTERNET-OWEGO
> Date: 7/5/98 10:23 AM
>
>
> In a message dated 98-07-05 03:46:42 EDT, you write:
>
> <<
> I am a PCB fabricator in the UK and when we started using the electroless
> Nickel and Immersion Gold process we noticed a curious phenomenon. If the
> panels are immersed in DI water or mains water after processing, then
> exposed to air for a minute or two before drying, the gold has reddish
> brown
> stains in random areas. Although this did not seem to affect solderability
> to any noticeable extent, it was not cosmetically attractive.
>
> I would like to have an explanation for this mechanism. The immersion gold
> is 0.15 microns max (6 millionths of an inch) over 4 microns (0.00016") of
> electroless nickel. As this occurs with DI or mains water, contamination of
> the water does not seem to be a factor, but simply exposure to air at room
> temperature when the surface is wet. >>
>
>
> Paul:
>
> Given the thiness of the EN (and Au), I would bet the problem is likely one
> of
> porosity, and having some exposed Copper here and there. And porosity
> driven
> by our industry's great nemisis, galvanic corrosion, would give you exactly
> what you are seeing.
>
> Further, I would bet that thicker EN ( 2-3X) would stop the problem.
>
> Rudy Sedlak
> RD Chemical Company
>
> ################################################################
> TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
> ################################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with following
> text
> n the body:
> To subscribe: SUBSCRIBE TechNet <your full name>
> To unsubscribe: SIGNOFF TechNet
> ################################################################
> Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section
> for
> ditional information.
> For technical support contact Hugo Scaramuzza at [log in to unmask] or
> 847-509-9700
> t.312
> ################################################################
>
>
>
> ################################################################
> TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
> ################################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with following
> text in the body:
> To subscribe: SUBSCRIBE TechNet <your full name>
> To unsubscribe: SIGNOFF TechNet
> ################################################################
> Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section
> for additional information.
> For technical support contact Hugo Scaramuzza at [log in to unmask] or
> 847-509-9700 ext.312
> ################################################################
>
>
################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following
text in the body:
To subscribe: SUBSCRIBE TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for
additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700
ext.312
################################################################
################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe: SUBSCRIBE TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################
|
