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TechNet E-Mail Forum <[log in to unmask]>, Randy <[log in to unmask]>
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Mon, 4 Jan 2010 09:55:32 -0600
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Can someone please help me break my paradigm with "filling vias in 
process with solder"?  I have difficulty seeing how this works.  How do 
you ensure consistent, predictable solder fill in thermal vias during 
assembly?  If inconsistent, then you really can’t count on it to be there 
since any time it’s not there you’ll pay for it.

If by some chance you can get solder to fill all vias completely, then 
how do you avoid solder flowing out the opposite end of the vias?  
Protruding solder “bumps” can interfere with solder paste printing if 
bottom (second) side assembly is required.  These solder “bumps” can 
also interfere with heat sinking if intimate contact is required in this 
area for heat dissipation.

Regards,
Randy


On Tue, 29 Dec 2009 12:28:35 -0800, Dwight Mattix 
<[log in to unmask]> wrote:

>Practically speaking, using "thermal conductive" and "CB100" in the
>same sentence is an oxymoron.
>
>
>Cu ~= 300 w/mK
>Solder, Ormet, et al ~= 25 w/mk
>CB100 ~=3 w/mK
>
>Small amount more annular copper, filling with Ormet paste (not a
>cheaper option though) or filling via in process with solder yields
>much greater increase in thermal conductivity than CB100.
>
>At 11:55 AM 12/29/2009, Joe Lara wrote:
>>Hello TechNetter's,
>>
>>Im currently using Du Ponts "CB-100" Conductive Paste to vill Vias
>>at $400 per 100G. Is
>>there a more affordable way of filling vias that call out to be
>>filled (thermal conductive) and
>>plated?
>>
>>
>>Best Regards,
>>
>>Joe
>>
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