Microelectronic Equipment Research Articles

Hydrothermal growth of large-scale macroporous TiO2 nanowires and its application in 3D dye-sensitized solar cells

Large-scale macroporous TiO2 nanowires (MTN) were directly grown on spiral-shaped titanium wires as photoanodes of dye-sensitized solar cells (DSSCs) via a facile hydrothermal reaction without any seeds, templates, and TiO2 powder. The MTN thin film was characterized by SEM, XRD and TEM. The studies revealed that the MTN thin film had better mechanical properties and provided an efficient pathway for the diffusion of liquid electrolyte. The efficiency of 0.86% for the 3D DSSC was obtained with a Jsc of 2.30 mA/cm2, Voc of 616 mV, and FF of 0.61. This MNT-based mini 3D DSSC is a promising photovoltaic device for applications in the fields of high-integrated micro-electronic equipment.

Investigation of static and dynamic characteristics of a piezomotor for nano-and micrometric movements

Static and dynamic characteristics of a piezomotor of nano-and micrometric movements for nanotechnology and microelectronics equipment are calculated, the parametric structural diagram of the piezomotor is constructed, and the influence of physical and geometric parameters of the piezomotor on the static and dynamic characteristics is determined.

Influence of a pore‐former and PTFE in the performance of the direct ethanol fuel cell

AbstractThe direct ethanol fuel cell (DEFC) is a promising fuel cell device, which could provide power to portable and microelectronic equipment in the future. In the present investigation, the influence of a pore‐former, polytetrafluoroethylene (PTFE) and catalyst loadings in the electrocatalyst of the anode on DEFC performance is studied. The decal transfer method is used to prepare the membrane electrode assembly (MEA) using PtRu/C (40:20% by wt) as the anode catalyst, and Pt/C (40% by wt) as the cathode catalyst, a pore‐former, PTFE dispersion and Nafion ionomer. The pore‐former used is 10% (by wt) NaHCO3 in the catalyst ink during the preparation of MEA. The voltage‐current characteristics of DEFC were monitored at different loadings of the catalyst, PTFE and a pore‐former in MEA. The DEFC performance improved with the use of a pore‐former and higher loading of PTFE in MEA. Higher DEFC performance is obtained because PTFE, along with the network of pores in the anode side allowed easy removal of reaction species, thereby rendering the catalyst site available for ethanol oxidation. Further, the use of a pore‐former and PTFE at the anode allowed higher loading of electrocatalyst resulting in an increase in the performance of DEFC. The DEFC, with 1 mg cm−2 of catalyst loading at the anode and cathode, 10% (by wt) NaHCO3 of a pore‐former, 20% (by wt) PTFE loading in catalyst ink gives maximum power density of 8.5 mW cm−2 at a current density of 31.3 mA cm−2. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.

Road vehicle-induced vibration control of microelectronics facilities

A hybrid control platform is investigated in this paper to mitigate microvibrations to a group of vibration-sensitive equipment installed in a microelectronics facility subject to nearby road vehicle-induced horizontal and vertical ground motions. The hybrid control platform, on which microelectronics equipment is installed, is mounted on a building floor through a series of passive mounts and controlled by hydraulic actuators in both horizontal and vertical directions. The control platform is an elastic body with significant bending modes of vibration, and a sub-optimal control algorithm is used to manipulate the hydraulic actuators with actuator dynamics included. The finite element model and the equations of motion of the coupled platform-building system are then established in the absolute coordinate to facilitate the feedback control and performance evaluation of the platform. The horizontal and vertical ground vibrations at the base of the building induced by nearby moving road vehicles are assumed to be stationary random processes. A typical three-story microelectronics building is selected as a case study. The case study shows that the vertical vibration of the microelectronics building is higher than the horizontal. The use of a hybrid control platform can effectively reduce both horizontal and vertical microvibrations of the microelectronics equipment to the level which satisfies the stringent microscale velocity requirement specified in the Bolt Beranek & Newman (BBN) criteria.

Thermal Management of Microelectronic Equipment: Heat Transfer Theory, Analysis Methods, and Design Practices. ASME Press Book Series on Electronic Packaging

Thermal Management of Microelectronic Equipment: Heat Transfer Theory, Analysis Methods, and Design Practices. ASME Press Book Series on Electronic Packaging

Evolution of cooling technology for electrical, electronic, and microelectronic equipment

Selected aspects of cooling technology for electrical apparatus and electronic devices are considered for the past 80 years. The emphasis is on the past 50 years. The technology has evolved to meet the challenges of microminiaturization, and heat transfer considerations are now an integral part of the design procedure for microelectronic systems.

Modeling of highly multimode waveguides for time-domain simulation

Optical interconnection technology on the printed circuit board level is a key technology for future microelectronic equipment. Its industrial application requires sophisticated processes and technologies for the manufacturing as well as the design. In this paper, a modeling approach for a static and a time-domain simulation of board-integrated highly multimode optical waveguides with manufacturing based rough surfaces is presented. The transfer behavior of the waveguides is determined by a numerical computation of the step response using a Monte Carlo based ray tracing procedure. The step response is piecewise approximated by exponential functions in order to obtain an analytical representation of the pulse response. This approach allows the application of very fast semi-analytical recursive convolution algorithms.

Natural convection in a square cavity with a heat generating body: Entropy consideration

Conjugate heat transfer in a cavity is an important consideration with regard to cooling of micro-electronic equipment. In the present study, a heat transfer analysis of conditions taking place in a square cavity with a heat source, located in it, is carried out. The natural convection accompanying conduction heat transfer in the heat generating solid body is examined. Air or water are considered as the fluid in the cavity while steel substrate is considered as the heat generating solid body. The location of the solid is changed in the cavity to examine the cooling conditions. The entropy analysis of the system is carried out to determine the irreversibility ratio for each location of the solid body in the cavity. It is found that the heat transfer from the solid body surfaces increases where the surfaces facing the inlet and the exit of the cavity. The entropy generated attains the maximum value for air when the solid body is located at the center of the cavity; in which case, the irreversibility ratio reduces to a minimum value.

Heat transfer in cooling systems of microelectronic equipment with partially submerged condensers

The heat transfer in a liquid immersion cooling system for microelectronic equipment was tested. The internal volume of the module was divided into two parts with a special partition. Inert dielectric liquid MDSF was used in the experiments as a working fluid. The proposed system can reduce the influence of noncondensable gas on heat transfer at the vapor space condenser. It was determined that the average heat transfer coefficient does not substantially decrease during the condensation of vapor on the partially submerged tubes; this is due to the effect of the surface-tension-driven pressure gradient which occurs in the film of the condensate.

Thermal performance of an MCM flip-chip assembly in liquid nitrogen

A complementary metal-oxide-semiconductor (CMOS) microprocessor module could operate faster and more efficiently in liquid nitrogen due to high heat removal, faster gate speeds, and increased material conductivity. A high-power flip-chip test vehicle was fabricated consisting of 12 0.40 cm/sup 2/ thermal test chips each containing a heater and thermal diodes bonded with conductive epoxy onto a Si substrate and packaged in a 1.5-in cavity ceramic flatpack. Under pool boiling conditions in liquid nitrogen with no lid, the thermal resistance was 0.15 K/W in the nucleate boiling regime up to a total power of 50 W where film boiling began. However, it is undesirable to have bare chips in any microelectronic equipment due to reliability considerations. A standard hermetic lid increased the overall thermal resistance to nearly 4 K/W due to the presence of a 10 mil gas gap between the lid and the flip-chips. This was unacceptably high for cryogenic operation. This thermal resistance was lowered by an order of magnitude with the help of thermally conductive interface materials to fill this gap and by the addition of a pin fin heat spreader to retard the onset of film boiling. In this configuration, the test vehicle could dissipate over 115 W (24 W/cm/sup 2/ on a chip area basis) with only a 50 K rise in temperature above the saturation temperature of liquid nitrogen. This level of thermal performance will enable a CMOS multichip module (MCM) processor module with a protective lid in place to operate at high power while taking advantage of the speed-enhancing characteristics of cryogenic operation.

Study on the Laminar Mixed Convective Heat Transfer in Three-Dimensional Channel With a Thermal Source

In this paper, the mixed convective heat transfer phenomena in a three-dimensional channel with one heating-element is studied. A general-purpose computer program is developed to analyze the flow field and temperature distribution in the channel. In order to ensure the accuracy of result, numerical computation is performed by using the alternating direction implicit (A.D.I.) method based on the SIMPLER algorithm. This paper deals with fundamental heat transfer phenomena in “L.S.I.” package, which is used extensively in microelectronic equipment. The influences of Reynolds number and Grashof number on the Nusselt number of the heating-element are discussed. In order to make it easier for readers to understand the phenomena studied in this paper, three-dimensional streaklines and three-dimensional isothermal surfaces are presented.

<Paper>The Introduction of Micro-Electronics Equipment and Small and Medium Enterprises

<Paper>The Introduction of Micro-Electronics Equipment and Small and Medium Enterprises

Improvements in Workforce Qualifications: Britain and France 1979–88

It is now widely recognised in advanced industrialised countries that ability to exploit technological innovation competitively is dependent upon the levels of skill available in the working population. In the early 1960s, both France and Britain took steps to remedy the problem of levels of craft and technician-level skills which were inferior to those of Germany. In the intervening twenty years, these intermediate skill levels have become increasingly important, in particular for manufacturing efficiency as micro-electronic control equipment and the efficient logistical organisation of production demand a new and wider range of technical services to maximise machinery utilisation and to combine it with the satisfaction of more sophisticated consumer requirements.

An Interfacing Software Package for Thermal Analysis: Application to Microelectronics

A software package called: INterfacing Software for Thermal ANalysis (INSTAN) is developed to interface finite element general purpose programs with finite-difference thermal network analyzers for detailed analysis of complex thermal problems. The finite element mesh is used to generate the thermal network representation of the problem. INSTAN performs automatically the thermal network calculations and generates a complete input file for the thermal analysis program. The INSTAN software package is a powerful modeling tool which uses the preprocessing and postprocessing features available in a finite element program. It has also the flexibility and heat transfer calculation capabilities of a finite-difference program. It can handle problems with three-dimensional irregular geometries, time and temperature dependent properties, and anisotropic materials. The software possesses enhanced capabilities that make it suitable for thermal analysis of microelectronic equipment.

Stability of internally mixing flow

Hydrodynamic stability of viscous shear flow resulting from the mixing of two parallel streams of fluid along the centre line of a channel is investigated. A linear stability analysis is employed and eigenvalues are extracted using a variational principle combined with a Rayleigh-Ritz procedure. Velocity profiles for the base flow are obtained from a numerical solution of the laminar mixing problem. Results show a sharp drop in critical Reynolds number as the streams start to mix. However, the flow is generally stable at the mean flow Reynolds number investigated here. These results have practical implications for enhancing mixing and heat or mass transfer in thermal systems of small characteristic dimensions, as found in microelectronic equipment packages.

Heat transfer in electronic and microelectronic equipment 20th ICHMT international symposium Libertas Hotel, Dubrovnik, Yugoslavia, 29 August–2 September 1988

Heat transfer in electronic and microelectronic equipment 20th ICHMT international symposium Libertas Hotel, Dubrovnik, Yugoslavia, 29 August–2 September 1988

Does a Computer System Help to Teach a Sight Vocabulary to Children with Severe Learning Difficulties?

Over the past decade, interest in the use of microelectronic equipment with pupils with special educational needs has grown. Schools in the United Kingdom have been provided with a wealth of information from the Council for Educational Technology (CET), the four Special Education Microelectronic Education Resource Centres (SEMERCs), Aids to Communication in Education (ACE) centre, and the Microelectronics Education Programme (MEP) on hardware and software currently available. Despite the great national interest in microtechnology, investigation of the prevalence and use of microcomputers in special schools indicates that the microcomputer is underutilized. A survey of special schools in Surrey local education authority (September 1985) indicated that of the 70 special schools and units in the authority, 24 percent did not have a micro at all, and 70 percent had only one. Very few schools had any access to specialized input and output devices (switches, concept keyboards, voice synthesizers, etc.). Frequen...

Permanent secretarles, managing directors and microelectronics

Summary Microelectronic equipment has profound effects throughout any organization, large or small, in any sector. Good and bad effects can occur at the same time. Benefits may include direct improvements to the organization's results, secondary benefits to the workforce, and external benefits, e.g. to customers or the general public. Negative effects may include non‐use or under‐use of the equipment, deterioration of the organization's output, disruption in other departments, disruption in outside organizations such as suppliers, a series of staff difficulties; leading to possible disaster for small commercial organizations and to loss of profit and/or reputation for large ones. In this respect the whole world is ‘developing’. Some ‘developing’ countries in Southeast Asia may be further forward than ‘industrialized’ countries. Only the executive heads of organizations have the breadth of view and responsibility to take into account all kinds of difficulty and their causes, as well as all kinds of benefit...

Packaging techniques for modern microelectronics equipment : F. A. Robertson. Electronics & Power, October (1971), p. 406

Packaging techniques for modern microelectronics equipment : F. A. Robertson. Electronics & Power, October (1971), p. 406

Packaging techniques for modern microelectronics equipment

It is not easy for a designer to decide the form that electronic circuit packages should assume; this article explains packaging problems in the past, and presents a pattern of design for the future