Normally, it is fine to go for secondary reflow (as it is design at the
secondary side of the board) but you want to play safe, you can use a
carrier but the reflow oven setting needs to be changed accordingly.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian
Sent: Friday, 24 April 2009 8:07 AM
To: [log in to unmask]
Subject: Re: [TN] Second time reflow of PoP on bottom side of PCBA

Peter,
It will depend on the weight of the two parts of the PoP compared to the
surface tension of the solder joints and the vibration or lack of
vibration of your conveyor system. Also check how much cumulative heat
the component supplier recommends. 
Bev
RIM

----- Original Message -----
From: TechNet <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Sent: Thu Apr 23 20:00:12 2009
Subject: [TN] Second time reflow of PoP on bottom side of PCBA

Hello technet

I am reviewing an application involving PoP (14mm package on package) 
placed on the side A of the board, side B involves placement of multiple
SMT 
connectors (USB etc) therefore it's necessary to process them last. 

My question is whether anyone sees a problem with the PoP device on side
A 
going through a 2nd time reflow during side B processing? Would I need
to 
utilize a reflow carrier to shield side A to avoid secondary reflow of
the PoP 
device?

Any input is appreciated. Thanks.

Peter

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