Rainer,

A second thought, depending upon what your overall objectives are.

I have printed/written various metalo-orgainc inks and polymer thick film inks on glass - typically Ag's, but their leach resistance is poor.  Their adhesion is outweighed by how quickly some of them leach.  Their wetting characteristics are not necessarily the same either and would likely not work out very well for solder paste wetting and flow characterizations.

With a decent automated dispenser, you can get down to 254um [10 mil] line and space if you desire.

Possibly you can do this in-house?


Steve Creswick
Sr Associate - Balanced Enterprise Solutions

http://www.linkedin.com/in/stevencreswick
                         616 834 1883



-----Original Message-----
From: Steven Creswick [mailto:[log in to unmask]] 
Sent: Monday, July 21, 2014 10:14 AM
To: 'TechNet E-Mail Forum'
Subject: RE: [TN] Dummy Glass QFN

Rainer,

I understand what you are looking for, as we did it ourselves.

You need to find a thin film house that can deposit NiC [or Ti], Ni [or Cu], Au [flash] in the pattern you desire onto the glass substrate.  

My experience has been that this works well for cleaning evaluations and underfill flow evaluations [but the wetting characteristics are not exactly the same as a laminate...], but I would not put any merit in mechanical test results [such as temp cycle, etc.] as the pads are much more likely to lift off the glass than your solder is to fail.

Once the array of patterns is deposited on the glass, just dice them apart and pick & place as if they were normal parts.

When I get back later today, I will see if I can dig up any possible sources for you.  In the mean time, I suggest looking for those that have thin film capability, or those that sputter [or evaporate] on glass routinely, such as optical filter manufacturers, etc.


Steve Creswick
Sr Associate - Balanced Enterprise Solutions http://www.linkedin.com/in/stevencreswick
                         616 834 1883





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