I have pics on this + one or two pages to read, if you want...nostalgia, but still used!

Ingemar



-----Original Message-----

From: TechNet [mailto:[log in to unmask]]

Sent: den 17 mars 2005 12:01

To: [log in to unmask]

Subject: Re: [TN] Shear Strength Test





Gregg - Werner,



Back in the olden-days of thick film circuits on alumina and such, we used a relatively standardized test throughout the Hybrid industry called a pull-peel test, using a "Shepard's Crook".  Since we used a lot of DuPont thick film materials at the time, they had a pseudo-standardized test that I was familiar with.



Let me see if I can explain...  The 'crook' looked like a shepard's staff.  The substrate to be tested was placed within the crook of the staff, with the shaft laying across the bond pads to be tested.  The overall staff was made of tinned copper wire of say 18-20 ga.



The 'assembly' was dipped into the solder pot [fixed time, temp, flux, etc].  The wires were carefully formed to a 90 vertical angle with respect the surface of the substrate - then pulled.  If the thick film conductive were decent [and if the aging conditions were not too extreme], the wire would pull out of the solder joint.  Worst case, the pad would come off the substrate.



I really don't think this will work for you as I would expect the wire to always pull out of the solder joint ... but thought it might be good to let you know in case you could adapt something.



There are a number of shear test equipment mfrs out there that can perform shear testing on various sized devices.  Our current Dage unit has transducers that allow us to shear gold ball bonds in the 20-50 gm range, or as much as 100Kg.  I will also attach their web link for your info.  http://www.dageinc.com/S4000.html



Sounds like you will have to be somewhat creative.



Steve

 



-----Original Message-----

From: Werner Engelmaier [mailto:[log in to unmask]]

Sent: Wednesday, March 16, 2005 6:58 PM

To: [log in to unmask]

Subject: Re: [TN] Shear Strength Test





Hi Gregg,

There is no such test; the reason for this is the fact that solder joints 

(when properly wetted) have ample strength for both use conditions and 

accelerated tests—thus, there really is no need for such a test.



Regards,

Werner Engelmaier

IPC—Chairman, Product Reliability Committee

Engelmaier Associates, L.C.

Electronic Packaging, Interconnection and Reliability Consulting

7 Jasmine Run

Ormond Beach, FL 32174 USA

Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904

E-mail: [log in to unmask], Website: www.engelmaier.com