Hi Inge, From what I can gather - 85C in 85% relative humidity. After the 1000 hours they do a controlled linear ramp to 25C/45% RH and then let the sample stabilize at this level for 4 hours then the test is done. I hope this answers your question. Regards Steve Kelly -----Original Message----- From: Inge [mailto:[log in to unmask]] Sent: June-25-08 3:31 PM To: Steve Kelly; 'TechNet E-Mail Forum' Subject: Re: [TN] Bias voltage test in damp heat Steve, you mean a 85/85 test without water vapour? Inge ----- Original Message ----- From: "Steve Kelly" <[log in to unmask]> To: "'TechNet E-Mail Forum'" <[log in to unmask]>; "'Inge'" <[log in to unmask]> Sent: Wednesday, June 25, 2008 12:21 PM Subject: RE: [TN] Bias voltage test in damp heat > Hi Inge, > The flex circuit has a BGA connector assembled on both ends and the test > is > done on the assembly. To my mind this is not a water vapour penetration > test. Regards Steve Kelly > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge > Sent: June-25-08 2:37 PM > To: [log in to unmask] > Subject: Re: [TN] Bias voltage test in damp heat > > Was the test performed on the flex itself and not the whole assembly? If > the > > answer is ' yes', I do understand better, because then the test was a > test > on the PI's resistance to humidity. With other words, a water vapour > penetration test. > Inge > > > ----- Original Message ----- > From: "Eric CHRISTISON" <[log in to unmask]> > To: <[log in to unmask]> > Sent: Wednesday, June 25, 2008 9:50 AM > Subject: Re: [TN] Bias voltage test in damp heat > > >> Alternatively you could suggest to the customer that they save time on >> qualification by ditching the 1000 hours 85/85 and simply submerge the >> equipment in a bucket of warm water for a day. The water uptake will be >> much the same. >> >> Good luck. >> >> >> >> Douglas O. Pauls wrote: >>> Steve, >>> I agree that this is madness, unless the telecom supplier has an end use >>> environment of 85/85 where power-on in humid conditions is a reality. >>> Assuming that the equipment is not functioning in a steam environment, >>> here is the "science" that you are looking for. >>> >>> Designers, when they have knowledge of the material characteristics, >>> will > >>> design spacings dependent on the dielectric strength or dielectric >>> withstanding voltage of the laminate. The values in the data sheets for >>> the laminates specify these parameters, but only for lab ambient >>> conditions, not after 85/85 conditioning. When you expose a hydrophilic >>> material to a long exposure in hot/humid conditions, then you don't have >>> that same dielectric strength (dramatically reduced) and you have >>> violated the design assumptions. Polyimide is such a hydrophilic >>> material. I believe Brian Ellis referred to it as blotter paper, in >>> which I would concur. If you allow the circuit to dry out, then you >>> return to the expected dielectric strength. You may already be at an >>> unrealistic threshold with 2500 volts/mm gradient, as Brian also pointed >>> out. >>> >>> Unless the designer had a firm value for dielectric strength of the >>> substrate after 85/85 conditioning, which would change as the substrate >>> rapidly dried out, then the design would not and could not work. >>> >>> Doug Pauls >>> >>> >>> >>> >>> Steve Kelly <[log in to unmask]> Sent by: TechNet <[log in to unmask]> >>> 06/25/2008 10:09 AM >>> Please respond to >>> TechNet E-Mail Forum <[log in to unmask]>; Please respond to >>> Steve Kelly <[log in to unmask]> >>> >>> >>> To >>> [log in to unmask] >>> cc >>> >>> Subject >>> [TN] Bias voltage test in damp heat >>> >>> >>> >>> >>> >>> >>> Good Day To All, >>> >>> Back in April I posted some queries on the tech-net about high voltage >>> testing after 85C/85RH testing and was basically told this test was >>> impossible and I agree with that assessment. But some things have a life >>> of >>> their own. >>> >>> To re-iterate: We are building a 4 layer flex circuit. All layers are 18 >>> micron copper and all lines and spaces assuming perfect etch are 100 >>> micron >>> lines and 100 micron spaces. My customer for some reason signed up to >>> pass a >>> 250 volt test after 1000 hours of 85C/85RH damp heat test. My premise is >>> being in this case a polyimide build if they dried the circuit after >>> this >>> test it should pass. They do not want to dry it and still have it pass. >>> The previous threads in summary said this test was "madness" - I agree >>> but >>> what is the scientific explanation of why this is madness. >>> Please note this requirement is being driven by very large telecom >>> companies >>> and the worlds largest provider of internet gear. >>> Thanks again for the help. >>> >>> Regards Steve Kelly >>> >>> >>> Steve Kelly >>> >>> (416) 750-8433 (work) >>> >>> (416) 750-0016 (fax) >>> >>> (416) 577-8433 (cell) >>> >>> >>> >>> --------------------------------------------------- >>> Technet Mail List provided as a service by IPC using LISTSERV 15.0 >>> To unsubscribe, send a message to [log in to unmask] with following text >>> in >>> the BODY (NOT the subject field): SIGNOFF Technet >>> To temporarily halt or (re-start) delivery of Technet send e-mail to >>> [log in to unmask]: SET Technet NOMAIL or (MAIL) >>> To receive ONE mailing per day of all the posts: send e-mail to >>> [log in to unmask]: SET Technet Digest >>> Search the archives of previous posts at: >>> http://listserv.ipc.org/archives >>> Please visit IPC web site >>> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional >>> information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 >>> ext.2815 >>> ----------------------------------------------------- >>> >>> >>> --------------------------------------------------- >>> Technet Mail List provided as a service by IPC using LISTSERV 15.0 >>> To unsubscribe, send a message to [log in to unmask] with following text >>> in >>> the BODY (NOT the subject field): SIGNOFF Technet >>> To temporarily halt or (re-start) delivery of Technet send e-mail to >>> [log in to unmask]: SET Technet NOMAIL or (MAIL) >>> To receive ONE mailing per day of all the posts: send e-mail to >>> [log in to unmask]: SET Technet Digest >>> Search the archives of previous posts at: >>> http://listserv.ipc.org/archives >>> Please visit IPC web site >>> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional >>> information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 >>> ext.2815 >>> ----------------------------------------------------- >>> >>> >> >> -- >> Eric Christison Msc >> Mechanical Engineer >> Consumer & Micro group >> Imaging Division >> >> STMicroelectronics (R&D) Ltd >> 33 Pinkhill >> Edinburgh EH12 7BF >> United Kingdom >> >> Tel: +44 (0)131 336 6165 >> Fax: + 44 (0)131 336 6001 >> >> --------------------------------------------------- >> Technet Mail List provided as a service by IPC using LISTSERV 15.0 >> To unsubscribe, send a message to [log in to unmask] with following text in >> the BODY (NOT the subject field): SIGNOFF Technet >> To temporarily halt or (re-start) delivery of Technet send e-mail to >> [log in to unmask]: SET Technet NOMAIL or (MAIL) >> To receive ONE mailing per day of all the posts: send e-mail to >> [log in to unmask]: SET Technet Digest >> Search the archives of previous posts at: >> http://listserv.ipc.org/archives >> Please visit IPC web site >> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 > >> for additional information, or contact Keach Sasamori at [log in to unmask] >> or > >> 847-615-7100 ext.2815 >> ----------------------------------------------------- >> > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to > [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to > [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: http://listserv.ipc.org/archives > Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 > for additional information, or contact Keach Sasamori at [log in to unmask] or > 847-615-7100 ext.2815 > ----------------------------------------------------- > > > --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------