Nancy, Fab requirements are probably getting tighter (we spec 6.45 micrograms/in2 NaCl for PCBs which is/was Bellcore) because assembly outgoing requirement per J-STD-001A 8.3.2 is 1.56 micrograms/cm2 NaCl (or 10.06 micrograms/in2 NaCl) ionic residues, same as IPC-RB-276. Specifying a tighter cleanliness standard for PCBs gives the assemblers a guardband. PCB suppliers should not have a problem meeting the tighter cleanliness spec if the PCBs go through a final cleaning prior to packaging and shipping. We've been at 6.4 for years without having any complaints from our suppliers, our PCBs typically come in the 2 - 4 microgram/in2 NaCl. My opinion of checking prior to Entek coating is that it's not necessary. A cleaning and microetch is part of the standard Entek process, so any residual contaminants on a PCB should be cleaned off in the Entek process. Others might have a different opinion. Tracy Tennant Micron Technology [log in to unmask] 30-JUL-1996 09:49:48.21 >From: [log in to unmask] >To: [log in to unmask],[log in to unmask],STHUMMEL,TTENNANT,MIKEPARRY >Subj: Fab-Ionic Contamination > >Dear Technet, > >I have a question about the ionic contamination limits stated in >the IPC-RB-276. > >Reference to IPC-RB-276 Section 3.13.3, it is specified the >resistivity shall not be less than 10.06 micrograms/sq.inch of >sodium chloride. > >I have discovered that many OEM's are requiring this to be 6 >micrograms/sg. inch. > >Is this left over from the Mil-Spec days? > >Also > >Should boards that are checked before Entek Application be >required to be 6 micrograms per sq/inch as well? > > >Thanks, > > >Nancy Nelson >Dell Computer >[log in to unmask] > >*************************************************************************** >* TechNet mail list is provided as a service by IPC using SmartList v3.05 * >*************************************************************************** >* To unsubscribe from this list at any time, send a message to: * >* [log in to unmask] with <subject: unsubscribe> and no text. * >*************************************************************************** > > > > *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************