tensile strength charts for the interface were developed as a function
of varying moisture content. A new fundamental strategy to test
and predict the reliability of critical interfaces in IC’s
substrate and packages was demonstrated.
To demonstrate this strategy, a
polyimide/nitride/ oxide/Si multilayer system from an IC was chosen
and quantitative measure of degradation of in the fundamental tensile
strength of interfaces due to controlled environment of moisture,
temperature and hold time was presented. The key to afford this
strategy is the Laser
Spallation Technique which is capable of measuring the fundamental
tensile strength and the FTIR spectroscopy which is capable of quantifying
the quantity of moisture present in the sample. The strategy allows
the prediction and optimization of device reliability during the
design phase itself avoiding the time consuming accelerated tests
that are presently employed by the industry.
Figure on the left is a schematic of the sample used
during experimentation, while the figure on the right is the result
of our analysis
focus of this research is to address fundamental issues related
to separation of basic features of lines, squares, and circular
patches of varying geometrical dimensions deposited on a mother
substrate and understand the mechanism of transfer to a target substrate,
including issues of bonding at the landing sites.
To bring out the advantages over traditional approaches,
features made from Al, gold, and polysilicon, shall be considered,
and transferred to flexible polymeric tapes, and Si wafers. As a
demonstration of future potential in constructing MEMS structures,
three basic building blocks-a beam bridge, a membrane diaphragm,
and an IC circuit on a flexible substrate, that are common to several
useful MEMS structures shall be developed.
More information to come shortly!