In this dissertation we propose several DFT techniques specific to 3D
stacked IC systems. The goal has explicitly been to create techniques that
integrate easily with existing IC test systems. Specifically, this means
utilizing scan- and wrapper-based techniques, two foundations
of the digital IC test industry.
First, we describe a general test architecture for 3D ICs. In this
architecture, each tier of a 3D design is wrapped in test control logic that
both manages tier test
pre-bond and integrates the tier into the large test architecture post-bond.
We describe a new kind of boundary scan to provide the necessary test control
and observation of the partial circuits, and we propose
a new design methodology for test hardcore that ensures both pre-bond functionality
and post-bond optimality. We present the application of these techniques to
the 3D-MAPS test vehicle, which has proven their effectiveness.
Second, we extend these DFT techniques to circuit-partitioned designs. We find
that boundary scan design is generally sufficient, but that some 3D designs require
special DFT treatment. Most importantly, we demonstrate that the functional
partitioning inherent in 3D design can potentially decrease the total test cost
of verifying a circuit.
Third, we present a new CAD algorithm for designing 3D test wrappers. This algorithm
co-designs the pre-bond and post-bond wrappers to simultaneously minimize test
time and routing cost. On average, our algorithm utilizes over 90% of the wires
in both the pre-bond and post-bond wrappers.
Finally, we look at the 3D vias themselves to develop a low-cost, high-volume
pre-bond test methodology appropriate for production-level test. We describe
the shorting probes methodology, wherein large test probes are used to contact
multiple small 3D vias. This technique is an all-digital test method that
integrates seamlessly into existing test flows. Our
experimental results demonstrate two key facts: neither the large capacitance
of the probe tips nor the process variation in the 3D vias and the probe tips
significantly hinders the testability of the circuits.
Taken together, this body of work defines a complete test methodology for
testing 3D ICs pre-bond, eliminating one of the key hurdles to the
commercialization of 3D technology.
| Identifer | oai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/45756 |
| Date | 17 August 2012 |
| Creators | Lewis, Dean Leon |
| Publisher | Georgia Institute of Technology |
| Source Sets | Georgia Tech Electronic Thesis and Dissertation Archive |
| Detected Language | English |
| Type | Dissertation |
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