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Browse Prior Art Database

Isothermal Creep Testing of C-4 Solder Alloys

IP.com Disclosure Number: IPCOM000108266D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 3 page(s) / 84K

Publishing Venue

IBM

Related People

Gonya, SG: AUTHOR [+2]

Abstract

A test method was disclosed that presents a simple and inexpensive way of simulating and quantitatively measuring the compressive creep response of .006" diameter C-4 solder joints in the Thermal Cooled Module (TCM). A Thermal Mechanical Analyzer (TMA) was used to measure the creep response of prefabricated .006" diameter solder balls under 200 psi at 80o (Fig. 1).

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This is the abbreviated version, containing approximately 64% of the total text.

Isothermal Creep Testing of C-4 Solder Alloys

       A test method was disclosed that presents a simple and
inexpensive way of simulating and quantitatively measuring the
compressive creep response of .006" diameter C-4 solder joints in the
Thermal Cooled Module (TCM).  A Thermal Mechanical Analyzer (TMA) was
used to measure the creep response of prefabricated .006" diameter
solder balls under 200 psi at 80o (Fig. 1).

      The TMA was modified by using an external power supply to the
furnace, a thermocouple with digital readout and constant pressure
nitrogen purge gas to maintain a uniform sample temperature of 80oC.
The 200 psi compressive stress was supplied using 9 grams of weight
transmitted by a quartz probe to three .006" diameter solder ball
specimens arranged in a triangular configuration with .006" spacing
between balls (Fig. 2).  This three-point contact system was used to
give an average and more uniform creep response of the particular
solder alloy specimens.  Even probe contact on all three balls was
achieved after very small deflections in the primary creep stage of
the solder alloy.  In addition, this method allowed sufficient weight
to be used for best accuracy of the TMA.

      Ball placement was done using an optical inspection microscope
and the quartz probe tip was reduced to .020" width for better
centering of the balls under the probe.  A chart recorder was used to
plot the output of the displacement transducer to measure directly
...