I hv encountered the same problem, but not on the ZIF socket, some other type
sockets.
It seems like you are getting capillary effect. Here are some suggestions.
1.      Just in case to need to check whether it is due to overspray, get a
piece  of "something", and cover over the ZIF socket. check the socket
        after  wv-soldering.

2.      Also you may try running thru' at either higher preheat or at lower 
        wave temperature (We are running at 235 deg. cel). If both do not help,

3.      check your flux content, there might be too much thinner.
 
4.      By the way, check the socket too, there might hv some residue orginally
        stained inside the socket contact area.
 
Good Luck !


Poh Kong Hui
Nera Electronics 
Email: [log in to unmask]
 
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At 01:21 5/7/96 -0400, you wrote:
>Date : 7/5/96 9:06
>Msg From: ATUL RASTOGI
>We are a contract manufacturer , doing mfg for a large PC
>company.Recently we have been facing a problem of flux residue coming
>on the contact area of ZIF socket used for Pentium.Due to this
>residue when Pentium is inserted in the socket and the mother board
>is powered on , it doesn't work.This happens due to the insulative
>nature of the flux residue.After multiple insertions of the Pentium
>it starts working.
>
>Our process is a no clean process and our mother boards are Entek CU
>106 coated.We are using spray as well as wave fluxer on our wave
>soldering machines.
>
>Does somebody has an answer or suggestions to this problem?
>
>Thanks
>Atul Rastogi
>Atul Rastogi
>
>
>