I don't know the specific designs in questions, so I can only make a 
     "semi-educated" guess.
     
     One reason is that boards in cellular phones are usually pure SMT, 
     with no through hole, and are also thin.  Running a thin board through 
     an HASL machine tends to potatoe chip it.  A gold finish requires no 
     heat excursion to fab the finished bare board. At component assembly  
     you don't have to run a pure SMT board over a wave so there is no 
     worry about gold in the wave machine.
     
     Gold is also a great way to get a co-planar surface.
     
     Component types such as COB or connectors requiring mechanical (not 
     soldered) connections can also drive this, but again I don't know your 
     designs.
     
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______________________________ Reply Separator _________________________________
Subject: Why Gold finish on Cell phone Boards
Author:  [log in to unmask] at Dell_UNIX
Date:    7/27/95 10:07 AM


          I was hoping someone out there could help me out and shed 
          some light on a question that I've been trying to get an 
          answer to for a couple of months now (with limited success).
     
               Why do the major cell phone manufacturers use gold
          as their preferred finish?
     
          I would appreciate any information.
     
          Regards,
          Steve Sabourin
          Hadco Corporation
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