Multichannel die probing increases test speed and lowers the overall cost of testing. A new high-density wafer probe card based on MEMS technology is presented in this paper. MEMS-based microtest-channels have been designed to establish high-speed low-resistance connectivity between the dieunder-test and the tester at the wafer level. The proposed test scheme can be used to probe fine pitch pads and interconnects of a new generation of 3-D integrated circuits. The proposed MEMS probe, which is fabricated with two masks, supports 10 6 lifetime touchdowns. Measurement results using a prototype indicate that the proposed architecture can be used to conduct manufacturing tests up to 38.6 GHz with less than −1-dB insertion loss while maintaining 11.4-m contact resistance. The measured return loss of the probe at 39.6 GHz is −12.05 dB.Index Terms-Automatic test equipment, design-for-testing, manufacturing test, MEMS probe, signal integrity, wafer probe card.
In low-power VLSI design good amount of power can be saved by using coding scheme such as Bus-Invert (BI). Such a coding scheme looks at successive words on a data bus and applies transformation to minimize the number of transitions. In this paper we propose Bus-Shift (BS) coding scheme that circularly shifts the data to minimize transitions. Power saving of BI is poor on average cases, and even that deteriorates with wider bus width. In comparison the proposed BS scheme performs better in both maximum and average cases. For wide bus the savings from BS gets slightly worse, but still performs better than BI. Simulation results show a saving margin of 14% in average cases for a 32 bit bus. Comparison is also made with Shift-Invert (SINV), another reported coding scheme. An implementation of BS in Cadence is presented.
the recognition of applied research and development of renewable energy applications at UNI and Iowa in general. Dr. Pecen established solar electric boat R & D center at UNI where dozens of students were given opportunities to design solar powered boats. UNI solar electric boat team with Dr. Pecen's supervision won two times a third place overall in World Championship on solar electric boating, an international competition promoting clean transportation technologies in US waters. He was recognized as an Advisor of the Year Award nominee among 8 other UNI faculty members in 2010-2011 academic year Leadership Award Ceremony. Dr. Pecen received a Milestone Award for outstanding mentoring of graduate students at UNI, and recognition from UNI Graduate College for acknowledging the milestone that has been achieved in successfully chairing ten or more graduate student culminating projects, theses, or dissertations, in 2011 and 2005.
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