The growing interest in the microvia processes as suggested by Darren, may solve some to problems, but they come with a cost.  No doubt SLC provides small via holes, but it has trade-off like lower peel strength and potential delamination may occur.  I suppose the idea of copper-filled via is that it can maintain the normal FHS of 10-12 mils and thus the manufacturing cost is much lower.  It can save design space such that the via can be drilled directly on the SMD pads without fear that the solder paste will flow through thus causing insufficient solder onto the components.
I hope the question I asked on "resin in via" is still fresh, it actually drives in the same direction that while we can maintain the same hole size, and we can at the same time reduce some manufacturing cost.  Anyway, I am also interested to know more about copper filled via, if anyone could further provide information concerning this area, I would be very much appreciate that.


regards
stella

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> From [log in to unmask] Fri Aug 23 11:36:39 1996
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> From: <[log in to unmask]> (Darren Hitchcock)
> Subject: re: FAB: Copper Filled Via's
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> There is a growing number of Board Fabricators offering microvias. 
>  Most of the microvia processes (SLC, laser, Dycostrate, etc.) are 
> capable of plating shut a via placed in a surface mount pad.  The 
> vias are in the .002" to .005" diameter range before plating.  The 
> microvia processes are used to plate blind vias from layers 1 to 2 
> and layers n to n-1.  These processes give you space to fan out 
> from dense surface mount packages by putting the via in the pads 
> and then using the routing room on layers 2 and n-1.
> 
> If you would like more information give me a call.
> 
> Darren Hitchcock
> (503) 359-2658
> [log in to unmask]
> 
> 
> 
> [log in to unmask] Wrote:
> | 
> | I need to know who is providing copper filled via 
> | holes for via hole in
> | surface mount pad design.... Thanx in advance for 
> help.....
> 
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