1 research outputs found
Design and testing of high-speed interconnects for Superconducting multi-chip modules
Superconducting single flux quantum (SFQ) circuits can process information at
extremely high speeds, in the range of hundreds of GHz. SFQ circuits are based
on Josephson junction cells for switching logic and ballistic transmission for
transferring SFQ pulses. Multi-chip modules (MCM) are often used to implement
larger complex designs, which cannot be fit onto a single chip. We have
optimized the design of wideband interconnects for transferring signals and SFQ
pulses between chips in flip-chip MCMs and evaluated the importance of several
design parameters such as the geometry of bump pads on chips, length of passive
micro-strip lines (MSL)s, number of corners in MSLs as well as flux trapping
and fabrication effects on the operating margins of the MCMs. Several test
circuits have been designed to evaluate the above mentioned features and
fabricated in the framework of 4.5-kA/cm2 HYPRES process. The MCMs bumps for
electrical connections have been deposited using the waferlevel electroplating
process. We have found that, at the optimized configuration, the maximum
operating frequency of the MCM test circuit, a ring oscillator with
chip-to-chip connections, approaches 100 GHz and is not noticeably affected by
the presence of MCM interconnects, decreasing only about 3% with respect to the
same circuit with no inter-chip connections