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60,264 Views 5 Replies Last post: Feb 21, 2012 5:47 PM by yu.yanfeng RSS
yu.yanfeng EDA JEDI 1,206 posts since
Jul 23, 2008
Currently Being Moderated

Feb 21, 2012 1:46 AM

Anyone use Isola 408HR Material here?

We used Isola 408HR in our designs  and found delamination is common during Pb-free assembly. Our fabs said they can't do more  to Iso 408HR, thye wish us to change other material. Do you use this type of material and see delamination is common?

 

Yanfeng

Pete Active 43 posts since
Nov 17, 2009
Currently Being Moderated
Feb 21, 2012 12:33 PM in response to: yu.yanfeng
Re: Anyone use Isola 408HR Material here?

We don't specify by manufacturer's material numbers, we list the criteria we need and let the vendor chose the material.  I don't think we've used 408HR, it exceeds what we normally require.  But I can tell you, based on the 408HR specifications most critical to surviving lead free soldering (Tg=200, Td=360, non-dicy, low CTE), you need a new assembly or fabrication vendor.  There's no way that material should be delaminating under normal reflow and wave, even with multiple cycles.  That's one of the more robust materials available!  FR408 is far more common, rarely delaminates, and is lower rated.

 

Start with handling and storage.  They may be collecting moisture at either tha fabriactor or assembler locations. Are they vacuum packed with humidity cards?  Could also be poor curing by the fabricator.

 

That material is specific for it's electrical properties.  If that's why you are using it in the first place, be very careful letting them change - it could affect your product performance.

 

Pete

les Lurker 1 posts since
Feb 21, 2012
Currently Being Moderated
Feb 21, 2012 1:22 PM in response to: yu.yanfeng
Re: Anyone use Isola 408HR Material here?

I have specified that material on millions of boards.  Have never seen or heard of a problem that was not caused by our depanelizing process (which was caused by poor fabs)

Vern_Wnek Aficionado 236 posts since
Feb 8, 2011
Currently Being Moderated
Feb 21, 2012 1:46 PM in response to: yu.yanfeng
Re: Anyone use Isola 408HR Material here?

I agree with the answers here. I have always called out per the IPC Slash sheets, allowing the fab house to choose the best fit for material to the process. This holds them responsible for the Workmanship specification of the Slash sheets and other notes on the drawing.

 

See Attached.

 

I also agree HR408 should not be giving you lamination issues. So it could be uneven plane structures within your design, or a few other items. If it is planes, you may try adding copper theiving to the uneven layers.

 

Good Luck Yanfeng!

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