For electrical considerations, some designers will use an automatic 
     fill command to put ground plane in "open" areas of their boards.  
     This will, in most cases, also help out in current distribution during 
     plating.  But there is no such thing as a free lunch.  We are having 
     some (OK a lot of) discussion concerning the best fill geometry to 
     use.   The two main contenders are solid and cross hatching on 15 mil 
     centers.  My "opinion" concerning the two methods:
     
     Crosshatching 
         Advantages;  less Gerber data, better adhesion to FR-4 than bare 
     copper, cosmetically more appealing, less thermal mass for soldering 
     process
         Disadvantages;  (a major one)  Slivers,places where photoresist 
     can lift and redeposit [Our design system does not automatically 
     prevent formation of these slivers prior to producing a Gerber file], 
     hard to visually inspect 
     
     Solid fill
          Advantages;  No slivers, easier to inspect
          Disadvantages;  More gerber data, more thermal mass for soldering 
     processes, greater chance for discoloration of bare copper under 
     solder mask, less adhesion
     
     Our main concern is with the slivers associated with crosshatching.  
     Does anyone have suggestions concerning area sizes that should be 
     crosshatched?  Is there a better geometry to use?  What are you doing 
     to prevent slivers in your designs?
     
     Regards,
     Jamie Baumgart
     DSC Communications
     (214) 519-2500
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