Laser linking of metal interconnects: analysis and designconsiderations

Lateral connections between adjacent lines of metallization have been developed in order to achieve high density linking for customization in programmable gate arrays and for additive redundancy in restructurable integrated circuits. Links were formed by focusing a pulsed laser between two same-level aluminum lines. The mechanism of link formation appears to be the nucleation of a fissure, induced by the thermal expansion mismatch between the metallization and the surrounding dielectric (SiO₂) and passivation layer (Si₃N₄); molten aluminum fills the crack. Numerical simulation by the finite element method was carried out using a plane strain model. The probable path for the link-forming fissure, as predicted by the model on the premise that the local maximum tensile stress determines cracking, is shown to be consistent with experimental observations. Parametric analyses were performed to gain insights into the linking processes. It is found that damage in the passivation can be avoided by increasing the thickness of the dielectric between the aluminum and the passivation. Reducing the spacing between the metal lines increases the chance of successfully forming the link. Under certain conditions, the linking propensity can also be increased by reducing the metal width. In addition, the link is much easier to form when symmetric laser heating between the two metal lines can be achieved. These findings can be directly applied to improving the design of the laser linking processes and devices     

A systematic study of the energy independent behaviour of the fragmentation regions in16O-Em interactions from 3.7 to 200A GeV

The scaling behaviour in the fragmentation regions is investigated for¹⁶O-Em interactions from 3.7 to 200A GeV. It is found that in both the projectile- and the target-fragmentation regions, the multiplicity and pseudo-rapidity distributions as well as the two-particle pseudo-rapidity correlations are independent of incident energy. The intermittency indices at 14.6, 60 and 200A GeV are the same within the experimental errors, indicating that the limiting fragmentation hypothesis works with regard to dynamical as well as statistical fluctuations.     

Semiclassical statistical mechanics ofv-dimensional fluid mixture of hardv-spheres

The problem of calculating the equilibrium properties ofv-dimensional fluid mixture of hardv-spheres is studied. High temperature expansion for the density independent radial distribution function is derived for a hardv-sphere mixture. The ‘excess’ quantum corrections to the second virial coefficient and the excess free energy are also studied. Significant features are the large increase in ‘excess’ quantum correction with increasing dimensionality.     

Gravity effects on partially premixed flames: an experimental-numerical investigation

While premixed and nonpremixed microgravity flames have been extensively investigated, the corresponding literature regarding partially premixed flames (PPFs) is sparse. We report the first experimental investigation of burner-stabilized microgravity PPFs. Partially premixed flames with multiple reaction zones are established in microgravity on a Wolfhard–Parker slot burner in the 2.2 s drop tower at the NASA Glenn Research Center. Microgravity measurements include flame imaging, and thermocouple and radiometer data. Detailed simulations are also used to provide further insight into the steady and transient response of these flames to variations in g. The flame topology and interactions between the various reaction zones are strongly influenced by gravity. The flames widen substantially in microgravity. During the transition from normal to microgravity, the flame structure experiences a fast change and another relatively slower transient change. The fast response is due to the altered advection as the value of g is reduced, while the slow response is due to the changes in the diffusive fluxes. The radiative heat loss from the flames increases in microgravity. A scaling analysis based on a radiation Damköhler number is able to characterize the radiation heat loss.     

Particle Creation in the Oscillatory Phase of Inflaton

A thermal squeezed state representation of inflaton is constructed for a flat Friedmann–Robertson–Walker (FRW) background metric and the phenomenon of particle creation is examined during the oscillatory phase of inflaton, in the semiclassical theory of gravity. An approximate solution to the semiclassical Einstein equation is obtained in thermal squeezed state formalism perturbatively and is found obey the same power-law expansion as that of classical Einstein equation. In addition to that the solution shows oscillatory in nature except on a particular condition. It is also noted that, the coherently oscillating nonclassical inflaton, in thermal squeezed vacuum state, thermal squeezed state, and thermal coherent state, suffers particle production and the created particles exhibit oscillatory behavior. The present study can account for the postinflation particle creation due to thermal and quantum effects of inflation in a flat FRW universe.     

Selecting a Doctoral Programme Using the Analytic Hierarchy Process — The Importance of Perspective

This paper discusses the application of the analytic hierarchy process (AHP) to the selection of a doctoral programme. The first section of this paper includes a brief discussion of the AHP. In the next section, we describe a hierarchy for selecting a doctoral programme that includes the perspective or career objective of the decision-maker as what we call a pseudo-level. This is followed by an illustration of the hierarchy in a case study with MBA students contemplating a doctoral programme. Finally, we discuss the results and highlight the importance of perspective as a discrete criterion that should not be included as another level of the hierarchy in the usual way.     

Loss profiles: A quality of service measure in mobile computing

With rapid technological advances being made in the area of wireless communications it is expected that, in the near future,mobile users will be able to access a wide variety of services that will be made available over future high-speed networks. The quality of these services in the high-speed network domain can be specified in terms of several QOS parameters. In this paper we identify a new QOS parameter for the mobile environment, calledloss profiles, that ensuresgraceful degradation of service (for applications that can tolerate loss) in situations where user demands exceed the network's capacity to satisfy them. A new transport sub-layer is proposed that efficiently implements this new QOS parameter. We also show how this protocol can be easily incorporated into existing proposals for high-speed network transport layer protocols and into the MPEG-2 Transport System.This work was supported by the NSF under grant number NCR-9410357.