Circuit sensitivity to interconnect variation

Deep submicron technology makes interconnect one of the main factors determining the circuit performance. Previous work shows that interconnect parameters exhibit a significant amount of spatial variation. In this work, we develop approaches to study the influence of the interconnect variation on circuit performance and to evaluate the circuit sensitivity to interconnect parameters. First, an accurate interconnect modeling technique is presented, and an interconnect model library is developed. Then, we explore an approach using parameterized interconnect models to study circuit sensitivity via a ring oscillator circuit. Finally, we present an alternative approach using statistical experimental design techniques to study the sensitivity of a large and complicated circuit to interconnect variations     

Statistical process control in semiconductor manufacturing

The author presents a brief survey of standard SPC (statistical process control) schemes, and illustrates them through examples taken from the semiconductor industry. These methods range from contamination control to the monitoring of continuous process parameters. It is noted that, even as SPC is transforming IC production, the peculiarities of semiconductor manufacturing technology are transforming SPC. Therefore, the author describes novel SPC applications which are now emerging in semiconductor production. These methods are being developed to monitor the short production runs that are characteristic of flexible manufacturing. Additional SPC techniques suitable for in situ multivariate sensor readings are also discussed     

Multiple identity enactments and multiple personality disorder: A sociocognitive perspective.

People who enact multiple identities behave as if they possess 2 or more selves, each with its own characteristic moods, memories, and behavioral repertoire. Under different names, this phenomenon occurs in many cultures; in North American culture, it is frequently labeled multiple personality disorder (MPD). This article reviews experimental, cross-cultural, historical, and clinical findings concerning multiplicity and examines the implications of these findings for an understanding of MPD. Multiplicity is viewed from a sociocognitive perspective, and it is concluded that MPD, like other forms of multiplicity, is socially constructed. It is context bounded, goal-directed, social behavior geared to the expectations of significant others, and its characteristics have changed over time to meet changing expectations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semiconductor yield improvement: results and best practices

The results of a world-wide study on yield improvement are presented. Die yields collected from 21 fabs are transformed via a logit formula and compared. The die yields and die yield improvement rates of the fabs are compared, and manufacturing yield improvement practices are evaluated. Preliminary results of this continuing study indicate that die yield improvement is a function of computer-aided manufacturing practices and statistical process control practices in addition to commonly cited practices such as particle control and advanced manufacturing technology     

Control of photoresist properties: a Kalman filter based approach

The photolithography step in the semiconductor manufacturing process becomes increasingly critical as linewidths decrease for the next generation of integrated electronics. It therefore becomes necessary to reduce variations in photoresist parameters such as resist film thickness and photoactive compound concentration during manufacture. In this paper, we present a simple feedback scheme for accurately regulating these parameters. Our approach involves obtaining a simple, static process model the coefficients of which are recursively adjusted based on previous wafer measurements. We use this adaptive model to determine appropriate input setpoints for the next wafer. The effectiveness of this scheme in reducing process drift is exhibited by experimental data. Our results supports the widespread contention that modern feedback control offers the promise of improving the semiconductor manufacturing processes, often with relative ease and minimal capital cost     

Influence of carbon concentration and reaction temperature upon bainite morphology in Fe-C-2 Pct Mn alloys

Isothermal transformation of austenite to bainite was studied by optical, replication, and thin foil transmission electron microscopy (TEM) in both hypo- and hypereutectoid Fe-C-2 wt pct Mn alloys (and a single 3 pct Mn alloy) containing from 0.1 to 1.37 wt pct C in order to characterize and explain the transitions which occur in bainite morphology as a function of carbon content and reaction temperature. A “morphology map” was constructed showing the temperaturecarbon composition(T-x) regions in which four different bainite morphologies predominate: upper bainite, lower bainite, nodular bainite, and inverse bainite. Calculations of the volume free energy changes associated with the nucleation of ferrite, ?G _v ^α , and cementite, ?G _v ^c , and the parabolic rate constant for growth of ferrite, α_α, and cementite, α_c, were performed in order to explain the observed morphological transitions. In hypoeutectoid alloys, where |?G _v ^α | ? |ΔG _v ^c | and α_α ? α _c , the Widmanstätten ferrite-dominated morphologies of upper and lower bainite predominate. The upper-to-lower bainite transition appears to be associated with the emergence of edge-to-face sympathetic nucleation at high values of |ΔG _v ^α |. In hypereutectoid alloys, the ratios ΔG _v ^α /ΔG _v ^c and α_α/α_c are considerably smaller; hence, cementite can compete much more readily with ferrite during both nucleation and growth, resulting in the formation of nodular bainite. With decreasing temperature in the hypereutectoid regime,ΔG _v ^α /ΔG _v ^c , and especially α_ga/α_c, increase, resulting in the replacement of nodular bainite by lower bainite at temperatures below about 250 °C to 275°C.     

The four foundational groups required for a successful ICME approach

This article briefly outlines some of the roles of four foundational groups in fostering rapid growth and implementation of Integrated Computational Materials Engineering (ICME). These roles include development of ICME-related computational, experimental, and cyberinfrastructure tools, and training of the future ICME workforce, in order for ICME to realize its great potential. The four foundational groups considered here include: corporations, government organizations, universities, and professional societies. Finally, a discussion is provided of how materials societies can play an important role in convening the four foundational groups, and providing the venues and mechanisms for members from these groups to integrate and work together to enable ICME to flourish.     

Automated malfunction diagnosis of semiconductor fabricationequipment: a plasma etch application

A general methodology for the automated diagnosis of integrated circuit fabrication equipment is presented. The technique combines the best aspects of quantitative algorithmic diagnosis and qualitative knowledge-based approaches. Evidence from equipment maintenance history, real-time tool data, and incline measurements are integrated using evidential reasoning. This methodology is applied to the identification of faults in the Lam Research Autoetch 490 automated plasma etching system located in the Berkeley Microfabrication Laboratory     

Suggestions for altered auditory sensitivity, the negative subject effect and hypnotic susceptibility: A signal detection analysis.

In Experiment I, using 96 undergraduates, low susceptibles (Harvard Group Scale of Hypnotic Susceptibility, Form A) showed higher sensitivity than high susceptibles, and hypnotic induction failed to affect the sensitivity of either highs or lows. Among the high susceptibles, suggestion to either increase or decrease acuity produced increments in sensitivity and reduced individual differences. Suggestions (regardless of the direction of change suggested) probably motivated high susceptibles, who would have otherwise performed inefficiently, to perform as efficiently as low susceptibles. With respect to response bias, high-susceptible Ss given a suggestion for increased acuity behaved in terms of suggested demands; they showed an increased tendency to respond "signal." Low-susceptible Ss given the same suggestion responded in a counterdemand or "negative subject" fashion; they developed a bias to say "noise." Exp II used a more difficult discrimination task with 80 Ss to replicate and extend this counterdemand effect in low susceptibles. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Instructional demands and ratings of overt and hidden pain during hypnotic analgesia.

16 highly hypnotizable (Carlton University Responsiveness to Suggestion Scale) undergraduates rated the intensity of cold pressor pain during a baseline trial and again during 3 hypnotic analgesia trials. During each analgesia trial, Ss were instructed to give overt reports that reflected consciously experienced pain and covert reports that reflected the intensity of "hidden" pain. Treatment instructions administered before the 1st analgesia trial did not specify the relationship between overt and covert pain. Instructions given before the remaining 2 analgesia trials indicated that hidden pain would be either more or less intense than overt pain. Until they were given explicit information about the relative intensities of the pain, Ss reported no differences in the magnitude of overt and covert pain, contrary to the dissociation hypothesis of hypnotic analgesia. Consistent with social psychological formulations of the hidden observer phenomenon, Ss reported both higher covert than overt pain and lower covert than overt pain, depending on the instructions they were administered. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)