Workstation performance is improving at a rapid pace led by improvements in VLSI technology and system architecture. In the near future this trend will be limited by packaging unless similar improvements are made in the way we package the chips in high performance workstations. One approach is to use a multichip module to contain the entire processor function. We have developed a thin f i i multichip module for workstation applications. The prototype module contains a RISC processor consisting of nine CMOS VLSI chips. The package also contains decoupling capacitors and has 684 I/O. The substrate consists of a thin film structure fabricated on a silicon wafer using a polyimide dielectric and aluminum metal. All fabrication was done in an existing CMOS manufacturing line. IBM's C4 (controlled collapse chip connection) flip chip bonding technique was used to connect the CMOS VLSI chips to the package. The silicon substrate was packaged non-hermetically and connected to the next level of package using very high density surface mount flex cables. A clip-on heatsink was attached to the finished module which allows for up to 30 watts of power dissipation in the airflow found in a typical workstation environment.
Henry's law constants and infinite dilution activity coefficients of propane, propene, butane, 2-methylpropane,
1-butene, 2-methylpropene, trans-2-butene, cis-2-butene, 1,3-butadiene, dimethyl ether, chloroethane, and 1,1-difluoroethane in benzene, toluene, o-xylene, m-xylene, p-xylene, and styrene in the temperature range of (250 to
330) K were measured by a gas stripping method, and partial molar excess enthalpies and entropies were evaluated
from the activity coefficients. A rigorous formula for evaluating the Henry's law constants from the gas stripping
measurements was used for the data reduction of these highly volatile mixtures. The estimated uncertainties are
about 2 % for the Henry's law constants and 3 % for the infinite dilution activity coefficients. The Henry's law
constants followed the order of increasing Henry's law constant with decreases in the normal boiling point
temperature of the liquefied gas except polar gases. In general, the partial molar excess enthalpies and entropies
of gases in the aromatics increase with decreases of the polarities of the gases and increasing molecular size of
the gases.
The dependence of the total ionizing dose effect of continuously operating nMOS transistors, irradiated with gamma-ray from a Co60 source, on the on/off duty ratio of a gate voltage was studied. The transistors were manufactured by a 180 nm process. It was found that the maximum leak current in the case of 10% duty ratio was by a factor of about 100 less than the case of 90% duty ratio. To explain the observed result, a two-step reaction model was adopted, which describes the increase in the density of positively charged taps in an oxide layer and negatively charged interface traps. It was shown that a set of rate equations based on the proposed model can explain the observed dependence of the leak current on the duty ratio.
Circuits for CMOS two-dimensional (2-D) array data transfer are indispensable for applications such as space and nuclear fields. Issues include to be operated with higher speed, lower power, fewer size penalty and radiation hardness. To meet these requirements, two kinds of CMOS 2-D array data transfer circuits, such as a shift register type and a memory access type, are proposed and fabricated by the standard 0.18-µm CMOS process technology. In the both types, 16 µm pitch, 8×124 array data transfer operations were realized with data rate of more than 1 Gb/s. Furthermore, we conducted 60Co γ-ray irradiation experiments on those circuits. The current consumption ratio of the shift register type to the memory access type ranges from 150 to 200% as the dosage increases. The result indicate that the memory access type has better radiation hardness at 1 Gb/s than that of the shift register type.
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