TECHNET Archives

August 1997

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Subject:
From:
"Andrew J. Scholand" <[log in to unmask]>
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Date:
Fri, 15 Aug 1997 02:00:53 -0400
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Sitaraman and Sizemore have shown with parametric FEM studies that reducing
plated thickness from one oz to half oz thicknesses increases barrel stresses
and decreases corner stresses.

Experimental data gathered by Sleboda supported these modeling results,
showing that holding copper elongation and hole radius constant, PTH
reliability for corner cracking increases as plating thickness is decreased.

I believe someone also published an article showing that manufacturing
quality measures like waviness dominated plating thickness for PTH
reliability over a certain parameter range, but I can't find the reference.

So the answer depends I guess on where your failures are occuring.

Cheers,
        Andy


REFS:

Sizemore, J. and Sitaraman, S. K., "Elastic-Plastic and Elastic-Viscoplastic
Modeling of Plated-Through Holes in Solder Shock Test," HTD-Vol.
 319/EEP-Vol. 15, Cooling and Thermal Design of Electronic Systems, Ed. C. H.
Amon, SME International Mechanical Engineering Congress and Exposition, Nov.
12-17, 1995, San Francisco, CA, pp. 163-173.

Sleboda, T. J. "A study of Plated Through Hole Reliability of
Formaldehyde-Based Electroless Copper Depositions in Multilayer Board
Productions, M.S. Thesis in Material Science, Georgia Institute of
Technology, 1996.

----------
From:  GeoFranck [SMTP:[log in to unmask]]
Sent:  Thursday, August 14, 1997 5:10 PM
To:  [log in to unmask]
Subject:  [TECHNET] Design: Half Oz Copper

Colleagues,

Are there any studies which measure the thru hole realiability of HALF Oz
Copper vs ONE Oz copper?

Thanks
George Franck
Raytheon E-Systems
Falls Church Va


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