They varied from 3100 to 3800 V/mil. Andy Magee [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: Re: FW: Re[2]: Humidity Testing Author: Doug McKean::(MCKENDAB) at ~FABRIK Date: 7/12/96 5:05 AM From: Doug McKean Date: Fri, Jul 12, 1996 5:05 AM Subject: Re: FW: Re[2]: Humidity Testing To: "'IPC - Technet Input'" Andy, Just curious - What is the volt-per-mil rating of the material in between the traces supposed to be? Doug Dill, Norm J wrote: > > Andy, > Considering your test was run at 100 v with a .006" spacing, is there > any chance that airborne contaminants contributed to your 300/500 hour > failures? > > Norm Dill > [log in to unmask] > ------------------------ > Subject: Re[2]: Humidity Testing > Date: Wednesday, July 10, 1996 4:18PM > > We've done some testing on flex circuits and found that > there was about a 300 hour incubation period before visible > defects were evident on the failing circuits. Actual > electrical failures (shorting) took up to 500 hours. The > insulation resistance falls off early in the test as the > moisture reaches equilibrium in the polyimide, and then > falls further at about the time of the incubation period. > > The continuous bias voltage was 100V. 85C, 85%RH 100 mA > current limited, 0.006" spaces between traces. Measurements > were taken at 24, 48, 72, 144, 200, 300, 400, 500, 550 and > 1500 hours. > > Andy Magee - Applications Engineer > Rogers Corp - Circuit Materials Unit > Tel: (602) 917-5237 > Fax: (602) 917-5256 > E-Mail: [log in to unmask] > > ______________________________ Reply Separator > _________________________________ > > Subject: Re: Humidity Testing > Author: SIRGuru::(SIRGUR) at ~FABRIK > Date: 7/10/96 1:12 PM > > From: [log in to unmask] > Date: Wed, Jul 10, 1996 1:12 PM > Subject: Re: Humidity Testing > To: TechNet > I'll give you my favorite engineering answer - It depends. > > If you are trying to determine if a fabrication or assembly process > is > Bellcore-compliant, the answer is no. Bellcore compliancy is only > obtained > through the SIR and Electromigration testing in Chapter 13 of TR-78. > > If you are trying to determine if a vendor has acceptable product, > and you > don't really care about Bellcore compliance, then I would say the > answer is > yes. The seven day SIR test, IPC-TM-650, method 2.6.3.3 rev A, is an > alternative. > > The Bellcore electromigration test is 85C/85% RH, so is the SIR > method. > The Bellcore test goes 96 hours before the first measurement in an > unbiased > state, then a bias of 10 volts is applied. > The SIR test is biased from the start with a 50 volt bias. > The Bellcore test is not tied to an absolute resistance value. > The SIR test has a minimum of 100 megohms. > > I'm not really trying to bash the Bellcore electromigration test, but > I > understand the time constraint. In my opinion (that and 50 cents > gets you a > Diet Coke), you are best to do both methods concurrently. The SIR > test should > be able to allow you to make the decision in 7 days vs. 25 days. > Alternatively, you could interrupt the electromigration test after > 7-10 days > and see if you have any signs of corrosion or metal migration. It > has been > my experience that if you have not seen electromigration and > corrosion after > 7 days at 85/85 and a 50 volt bias, you would not see it in 500 > hours. > Again, my opinion. > > Hope this was helpful. If you want to discuss it in greater depth, > give me a > call at (317) 457-8095. > > Doug Pauls > CSL, Inc. > [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. * ***************************************************************************