[Beowulf] Whiskers and computer problems.

[Glen Gardner]

They don't like to use tin inside semiconductors.

At the board level tin can cause problems because solder contains a lot 
of tin.  
Also, many connectors have tin plated contacts. Heat, electrical charge, 
pressure from spring loaded
contacts, and time, exacerbate the situation.

Silver will act similarly.  Also, mating tin plated connectors with gold 
plated contacts can react with atmospheric moisture
and gases to cause a buildup of insulating materials that make a 
connector contact "go open" after a while.  This is why you
 should not mate tin plated memory boards into sockets with gold plated 
contacts.  You need to mate gold to gold,
and tin to tin. In fact, mating dissimilar metals in an environment 
where heat, contact pressure, electrical charge are
factors is a bad idea, period.

In general tin has a lot of nasty attributes.

Glen


Andrew Piskorski wrote:

>On Fri, Sep 24, 2004 at 10:53:24AM -0600, Robin Laing wrote:
>
>  
>
>>Tin Whisker (and Other Metal Whisker) Homepage
>>http://nepp.nasa.gov/whisker/index.html
>>    
>>
>
>Interesting, I had not heard about that.  Any idea how the
>semiconductor industry handles that, and how long have they been doing
>so?  I assume they do, as there's computer equipment ALL OVER modern
>fabs...
>
>  
>

-- 
Glen E. Gardner, Jr.
AA8C
AMSAT MEMBER 10593
Glen.Gardner at verizon.net


http://members.bellatlantic.net/~vze24qhw/index.html


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